Wooden box surface strengthening process based on nano coating

Abstract

The invention belongs to the technical field of wooden box body surface strengthening, and particularly relates to a wooden box body surface strengthening process based on a nano coating. The wooden box body surface strengthening process based on the nano coating comprises the following steps: preparing a coating component containing a polyurethane prepolymer, a curing agent, a viscosity modifier, a plasticizer, a nano reinforcing filler, reinforcing fibers, a flatting agent, a defoaming agent and a mildew preventive, wherein the coating component is prepared from the polyurethane prepolymer, the curing agent, the viscosity modifier, the plasticizer, the nano reinforcing filler, the reinforcing fibers, the flatting agent, the defoaming agent and the mildew preventive; mixing the coating components in a container to obtain a dip-coating paint; immersing the wooden box body to be treated into the prepared coating, and enabling the dip-coating coating to be attached to the surface of the wooden box body; and after the coating is preliminarily dried, the coating is cured through heating, and the surface-strengthened wooden box body is obtained. The uniform, firm and waterproof nano material coating is formed on the surface of the wooden box body, so that the mechanical strength and the waterproof performance of the wooden box body are remarkably improved, and the service life of the wooden box body is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of wooden box surface strengthening, and in particular relates to a wooden box surface strengthening process based on nano coating. Background Art

[0002] With the development of economy and the progress of society, people have higher and higher requirements for household goods and transportation packaging. Traditional wooden boxes have been widely used in daily life due to their natural beauty, environmental protection and renewable characteristics. However, untreated wooden boxes have some inherent defects, such as insufficient bending strength, easy deformation due to moisture, and susceptibility to mold erosion, which limit their use in high humidity or outdoor environments.

[0003] At present, the commonly used surface treatment methods for wooden boxes in the market mainly include paint, varnish and chemical modification. Although these methods can improve the durability and waterproofness of wood to a certain extent, they still have some shortcomings. For example, the traditional paint layer is usually thick and easy to peel off, and it cannot penetrate into the wood to form an effective protective layer; and chemical modification often uses harmful substances such as aldehydes and phenolic compounds during the treatment process, which affects the environment and health. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a surface strengthening process for a wooden box based on a nano-coating, the purpose of which is to significantly improve the mechanical strength and waterproof performance of the wooden box and extend its service life by forming a uniform, strong and waterproof nano-material coating on the surface of the wooden box; by utilizing specific coating components and their proportions, combined with dipping technology and subsequent thermal curing treatment, it is possible to simplify the production process and reduce production costs while ensuring the excellent performance of the coating.

[0005] The surface strengthening process of a wooden box body based on a nano coating provided by the present invention comprises the following steps:

[0006] a) preparing a coating component comprising a polyurethane prepolymer, a curing agent, a viscosity modifier, a plasticizer, a nano-reinforced filler, a reinforcing fiber, a leveling agent, a defoaming agent and a mildew preventer;

[0007] b) mixing the above coating components in a container to obtain a dip coating;

[0008] c) immersing the wooden box to be treated into the prepared coating so that the dip coating adheres to the surface;

[0009] d) After the coating is initially dried, the coating is cured by heating to obtain a surface-reinforced wooden box.

[0010] As a further optimization solution, the coating components include:

[0011] 1000 parts by mass of MDI polyurethane prepolymer;

[0012] 600-800 parts by weight of multifunctional alcohol curing agent;

[0013] 150 to 350 parts by weight of viscosity modifier;

[0014] 25 to 50 parts by weight of plasticizer;

[0015] 80 to 200 parts by mass of nano-reinforced filler;

[0016] 20-40 parts by weight of reinforcing fiber;

[0017] 5-10 parts by weight of leveling agent;

[0018] 3 to 6 parts by weight of defoamer;

[0019] 3 to 6 parts by weight of antifungal agent.

[0020] As a further optimization scheme, the multifunctional alcohol curing agent is selected from any one or more of the following components: polyoxypropylene glycol, polyoxyethylene glycol, polytetramethylene ether glycol, 1,4-butanediol ester glycol, and polycarbonate diol.

[0021] As a further optimization scheme, the viscosity modifier is selected from any one or more of the following components: acetone, ethyl acetate, and cyclohexanone.

[0022] As a further optimization scheme, the plasticizer is selected from any one or more of the following components: dibutyl phthalate, tributyl citrate, and dioctyl adipate.

[0023] As a further optimization scheme, the nano-reinforced filler is selected from any one or more of the following components: fumed silica, precipitated silica, fused silica, anatase titanium dioxide, and rutile titanium dioxide; the particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers.

[0024] As a further optimization scheme, the reinforcing fiber is selected from any one or more of the following components: chopped carbon fiber, continuous carbon fiber, carbon nanotube, and glass fiber.

[0025] As a further optimization scheme, the leveling agent is selected from any one or more of the following components: polydimethylsiloxane, polyether block amino silicone oil, and fluorosilicone.

[0026] As a further optimization scheme, the defoaming agent is selected from any one or more of the following components: silicone oil, fatty alcohol polyoxyethylene ether, and polydimethylsiloxane.

[0027] As a further optimization scheme, the mildew inhibitor is selected from any one or more of the following components: tributyltin hydrochloride, dodecyldimethylbenzyl ammonium bromide, mizolinone, and phenoxyethanol.

[0028] As a further optimization scheme, in step c), the prepared paint is poured into a dipping tank, and then the wooden box to be treated is also placed in the dipping tank, so that the opening of the wooden box faces downward and is completely immersed in the prepared paint, and ensure that every surface of the wooden box is in contact with the paint; the dipping time is 30 seconds to 60 seconds; during the dipping process, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every few seconds; during the dipping process, the wooden box is lifted and immersed several times.

[0029] As a further optimization scheme, in step d), after the dipping is completed, the wooden box is naturally dried for at least 24 hours, and then the wooden box is moved to an oven and heat-cured at 70 to 80 degrees Celsius for 2 to 4 hours.

[0030] Beneficial Effects

[0031] The nano-coating-based wooden box surface strengthening process provided by the present invention effectively improves the overall performance of the product by forming a nano-material coating on the surface of the wooden box. First, the coating significantly enhances the mechanical strength of the wooden box, and the bending strength is significantly improved, indicating that the coating not only strengthens the structural stability of the wood itself, but also gives the box higher durability and the ability to resist external stress. Secondly, the coating greatly improves the waterproof performance of the wooden box, and the surface water contact angle is significantly improved, which helps to prevent moisture penetration and plays a key role in extending the service life of wooden products in humid environments. In addition, the coating surface has high uniformity and smoothness, which effectively improves the appearance and quality of the box. DETAILED DESCRIPTION

[0032] The present invention is further illustrated by specific examples below. These examples are exemplary and are intended to illustrate the problem and explain the present invention, but are not intended to be limiting.

[0033] Through the following method, a strong and waterproof nano material coating is formed on the surface of the wooden box by a dip coating process, thereby improving the durability and protection ability of the wooden box.

[0034] Step S1: Preparation of coating components

[0035] 1000 parts by mass of MDI polyurethane prepolymer;

[0036] 600-800 parts by weight of multifunctional alcohol curing agent;

[0037] 150 to 350 parts by weight of viscosity modifier;

[0038] 25 to 50 parts by weight of plasticizer;

[0039] 80 to 200 parts by mass of nano-reinforced filler;

[0040] 20-40 parts by weight of reinforcing fiber;

[0041] 5-10 parts by weight of leveling agent;

[0042] 3 to 6 parts by weight of defoamer;

[0043] 3 to 6 parts by weight of antifungal agent.

[0044] The multifunctional alcohol curing agent is selected from any one or more of the following components: polypropylene glycol (PPG), polyethylene glycol (PEG), polytetramethylene ether glycol (PTMEG), 1,4-butanediol ester glycol (Polyester Diolbased on Adipic Acid and Butanediol, PDB), and polycarbonate diol (Polycarbonate Diol, PCDL).

[0045] The viscosity modifier is selected from any one or more of the following components: acetone (AC), ethyl acetate (EA), and cyclohexanone (CH).

[0046] The plasticizer is selected from any one or more of the following components: dibutyl phthalate (DBP), tributyl citrate (TBC), dioctyl adipate (DOA).

[0047] The nano-reinforced filler is selected from any one or more of the following components: aerosil (AS), precipitated silica (PS), fused silica (FS), anatase titanium dioxide (Anatase TiO 2 ,ATiO 2 ), Rutile TiO 2 ,RTiO 2 ). The particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers.

[0048] The reinforcing fiber is selected from any one or more of the following components: short carbon fiber (SCF), continuous carbon fiber (CCF), carbon nanotubes (CNTs), and glass fiber (GF).

[0049] The leveling agent is selected from any one or more of the following components: polydimethylsiloxane (PDMS), polyether block amino silicone oil (Polyether - Block - Amino - Siloxane, PEBAS), Fluorosilicone (FSi).

[0050] The defoaming agent is selected from any one or more of the following components: silicone oil (SO), fatty alcohol polyoxyethylene ether (APG), polydimethylsiloxane (PDMS).

[0051] The mildew preventer is selected from any one or more of the following components: tributyltin hydrochloride (Tri - n - butyltinChloride, TBTC), dodecyldimethylbenzyl ammonium bromide (Benzalkonium Chloride, BKC), mitazolone (Mitazolone, MTZ), phenoxyethanol (Phenoxyethanol, PE).

[0052] Step S2: Mixing of paint

[0053] In a clean container, first weigh the polyurethane prepolymer, curing agent and viscosity regulator in proportion and mix them evenly; then add the plasticizer, nano-reinforced filler, leveling agent, defoamer and mildew inhibitor, and stir thoroughly.

[0054] Step S3: Dip coating of wooden box

[0055] Pour the prepared paint into the dipping tank, and then put the wooden box to be treated into the dipping tank, so that the wooden box is completely immersed in the prepared paint, ensuring that every surface of the wooden box is in contact with the paint. The dipping time is 30 seconds to 60 seconds to ensure that the surface of the wooden box fully absorbs the paint. During the dipping process, in order to ensure the uniform distribution of the coating, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every 5 seconds, so that the wooden box rotates alternately clockwise and counterclockwise in the dipping tank. When the wooden box is completely lifted from the paint, repeat the dipping action 1 to 3 times to ensure the integrity and uniformity of the coating. After each dipping, gently shake off the excess paint and ensure that the surface of the wooden box is flat and there are no dripping marks.

[0056] Step S4: Curing of coating

[0057] After the dip coating is completed, the wooden box is placed in a well-ventilated environment to dry naturally for at least 24 hours to form a preliminary coating film on the surface of the wooden box. Subsequently, the wooden box is moved to an oven and heat-cured at 70 to 80 degrees Celsius for 2 to 4 hours. During this process, the coating is fully cross-linked to form a strong and dense surface. After the curing is completed, the wooden box is gradually cooled to room temperature in the oven to avoid cracking or peeling of the coating due to rapid cooling. Make sure that the wooden box is completely cooled before taking it out to obtain a high-strength and water-resistant wooden box reinforced with the coating.

[0058] Example 1

[0059] Step S1: Preparation of coating components

[0060] 1000 parts by mass of MDI polyurethane prepolymer;

[0061] 600 parts by mass of multifunctional alcohol curing agent;

[0062] 150 parts by mass of viscosity modifier;

[0063] 25 parts by mass of plasticizer;

[0064] 80 parts by mass of nano-reinforced filler;

[0065] 20 parts by mass of reinforcing fiber;

[0066] 5 parts by mass of leveling agent;

[0067] 3 parts by mass of defoamer;

[0068] 3 parts by mass of antifungal agent.

[0069] Step S2: Mixing of paint

[0070] In a clean container, first weigh the polyurethane prepolymer, curing agent and viscosity regulator in proportion and mix them evenly; then add the plasticizer, nano-reinforced filler, leveling agent, defoamer and mildew inhibitor, and stir thoroughly.

[0071] Step S3: Dip coating of wooden box

[0072] Pour the prepared paint into the dipping tank, and then put the wooden box to be treated into the dipping tank, so that the wooden box is completely immersed in the prepared paint, ensuring that every surface of the wooden box is in contact with the paint. The dipping time is 45 seconds to ensure that the surface of the wooden box fully absorbs the paint. During the dipping process, in order to ensure the uniform distribution of the coating, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every 5 seconds, so that the wooden box rotates alternately clockwise and counterclockwise in the dipping tank. When the wooden box is completely lifted from the paint, repeat the dipping action twice to ensure the integrity and uniformity of the coating. After each dipping, gently shake off the excess paint and ensure that the surface of the wooden box is flat and there are no dripping marks.

[0073] Step S4: Curing of coating

[0074] After the dip coating is completed, the wooden box is placed in a well-ventilated environment to dry naturally for 24 hours to form a preliminary coating film on the surface of the wooden box. Subsequently, the wooden box is moved to an oven and heat-cured at 75 degrees Celsius for 3 hours. During this process, the coating is fully cross-linked to form a strong and dense surface. After the curing is completed, the wooden box is gradually cooled to room temperature in the oven to avoid cracking or peeling of the coating due to rapid cooling. Make sure that the wooden box is completely cooled before taking it out to obtain a high-strength and water-resistant wooden box reinforced with the coating.

[0075] Among them, the multifunctional alcohol curing agent is polypropylene glycol (PPG); the viscosity modifier is acetone (AC); the plasticizer is dibutyl phthalate (DBP); the nano-reinforced filler is aerosil (AS). The particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers; the reinforcing fiber is short carbon fiber (SCF); the leveling agent is polydimethylsiloxane (PDMS); the defoaming agent is silicone oil (SO); the mildew inhibitor is tributyltin hydrochloride (Tri - n - butyltin chloride, TBTC).

[0076] Example 2

[0077] Step S1: Preparation of coating components

[0078] 1000 parts by mass of MDI polyurethane prepolymer;

[0079] 800 parts by mass of multifunctional alcohol curing agent;

[0080] 350 parts by mass of viscosity modifier;

[0081] 50 parts by mass of plasticizer;

[0082] 200 parts by mass of nano-reinforced filler;

[0083] 40 parts by weight of reinforcing fiber;

[0084] 10 parts by mass of leveling agent;

[0085] Defoaming agent 6 parts by mass;

[0086] 6 parts by mass of antifungal agent.

[0087] Step S2: Mixing of paint

[0088] In a clean container, first weigh the polyurethane prepolymer, curing agent and viscosity regulator in proportion and mix them evenly; then add the plasticizer, nano-reinforced filler, leveling agent, defoamer and mildew inhibitor, and stir thoroughly.

[0089] Step S3: Dip coating of wooden box

[0090] Pour the prepared paint into the dipping tank, and then put the wooden box to be treated into the dipping tank, so that the wooden box is completely immersed in the prepared paint, ensuring that every surface of the wooden box is in contact with the paint. The dipping time is 45 seconds to ensure that the surface of the wooden box fully absorbs the paint. During the dipping process, in order to ensure the uniform distribution of the coating, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every 5 seconds, so that the wooden box rotates alternately clockwise and counterclockwise in the dipping tank. When the wooden box is completely lifted from the paint, repeat the dipping action twice to ensure the integrity and uniformity of the coating. After each dipping, gently shake off the excess paint and ensure that the surface of the wooden box is flat and there are no dripping marks.

[0091] Step S4: Curing of coating

[0092] After the dip coating is completed, the wooden box is placed in a well-ventilated environment to dry naturally for 24 hours to form a preliminary coating film on the surface of the wooden box. Subsequently, the wooden box is moved to an oven and heat-cured at 75 degrees Celsius for 3 hours. During this process, the coating is fully cross-linked to form a strong and dense surface. After the curing is completed, the wooden box is gradually cooled to room temperature in the oven to avoid cracking or peeling of the coating due to rapid cooling. Make sure that the wooden box is completely cooled before taking it out to obtain a high-strength and water-resistant wooden box reinforced with the coating.

[0093] The multifunctional alcohol curing agent is polycarbonate diol (PCDL); the viscosity modifier is cyclohexanone (CH); the plasticizer is dioctyl adipate (DOA); the nano-reinforced filler is rutile titanium dioxide (Rutile TiO 2 ,RTiO 2 ); the particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers; the reinforcing fiber is glass fiber (GF); the leveling agent is fluorosilicone (FSi); the defoaming agent is polydimethylsiloxane (PDMS); and the mildew inhibitor is phenoxyethanol (PE).

[0094] Example 3

[0095] Step S1: Preparation of coating components

[0096] 1000 parts by mass of MDI polyurethane prepolymer;

[0097] 700 parts by weight of multifunctional alcohol curing agent;

[0098] 250 parts by mass of viscosity modifier;

[0099] 35 parts by mass of plasticizer;

[0100] 150 parts by mass of nano-reinforced filler;

[0101] 15 parts by mass of reinforcing fiber;

[0102] 8 parts by mass of leveling agent;

[0103] 5 parts by mass of defoamer;

[0104] 5 parts by mass of antifungal agent.

[0105] Step S2: Mixing of paint

[0106] In a clean container, first weigh the polyurethane prepolymer, curing agent and viscosity regulator in proportion and mix them evenly; then add the plasticizer, nano-reinforced filler, leveling agent, defoamer and mildew inhibitor, and stir thoroughly.

[0107] Step S3: Dip coating of wooden box

[0108] Pour the prepared paint into the dipping tank, and then put the wooden box to be treated into the dipping tank, so that the wooden box is completely immersed in the prepared paint, ensuring that every surface of the wooden box is in contact with the paint. The dipping time is 45 seconds to ensure that the surface of the wooden box fully absorbs the paint. During the dipping process, in order to ensure the uniform distribution of the coating, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every 5 seconds, so that the wooden box rotates alternately clockwise and counterclockwise in the dipping tank. When the wooden box is completely lifted from the paint, repeat the dipping action twice to ensure the integrity and uniformity of the coating. After each dipping, gently shake off the excess paint and ensure that the surface of the wooden box is flat and there are no dripping marks.

[0109] Step S4: Curing of coating

[0110] After the dip coating is completed, the wooden box is placed in a well-ventilated environment to dry naturally for 24 hours to form a preliminary coating film on the surface of the wooden box. Subsequently, the wooden box is moved to an oven and heat-cured at 75 degrees Celsius for 3 hours. During this process, the coating is fully cross-linked to form a strong and dense surface. After the curing is completed, the wooden box is gradually cooled to room temperature in the oven to avoid cracking or peeling of the coating due to rapid cooling. Make sure that the wooden box is completely cooled before taking it out to obtain a high-strength and water-resistant wooden box reinforced with the coating.

[0111] Among them, the multifunctional alcohol curing agent is polyethylene glycol (PEG); the viscosity modifier is ethyl acetate (EA); the plasticizer is dioctyl adipate (DOA); the nano-reinforced filler is aerosil (AS); the particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers; the reinforcing fiber is glass fiber (GF); the leveling agent is polyether block amino silicone oil (Polyether - Block - Amino -Siloxane, PEBAS); defoaming agent: fatty alcohol polyoxyethylene ether (Alkyl Polyglycoside, APG); mildew inhibitor: dodecyl dimethyl benzyl ammonium bromide (Benzalkonium Chloride, BKC).

[0112] Example 4

[0113] Step S1: Preparation of coating components

[0114] 1000 parts by mass of MDI polyurethane prepolymer;

[0115] 700 parts by weight of multifunctional alcohol curing agent;

[0116] 220 parts by mass of viscosity modifier;

[0117] 35 parts by mass of plasticizer;

[0118] 150 parts by mass of nano-reinforced filler;

[0119] 16 parts by mass of reinforcing fiber;

[0120] 8 parts by mass of leveling agent;

[0121] 4 parts by mass of defoamer;

[0122] 5 parts by mass of antifungal agent.

[0123] Step S2: Mixing of paint

[0124] In a clean container, first weigh the polyurethane prepolymer, curing agent and viscosity regulator in proportion and mix them evenly; then add the plasticizer, nano-reinforced filler, leveling agent, defoamer and mildew inhibitor, and stir thoroughly.

[0125] Step S3: Dip coating of wooden box

[0126] Pour the prepared paint into the dipping tank, and then put the wooden box to be treated into the dipping tank, so that the wooden box is completely immersed in the prepared paint, ensuring that every surface of the wooden box is in contact with the paint. The dipping time is 45 seconds to ensure that the surface of the wooden box fully absorbs the paint. During the dipping process, in order to ensure the uniform distribution of the coating, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every 5 seconds, so that the wooden box rotates alternately clockwise and counterclockwise in the dipping tank. When the wooden box is completely lifted from the paint, repeat the dipping action twice to ensure the integrity and uniformity of the coating. After each dipping, gently shake off the excess paint and ensure that the surface of the wooden box is flat and there are no dripping marks.

[0127] Step S4: Curing of coating

[0128] After the dip coating is completed, the wooden box is placed in a well-ventilated environment to dry naturally for 24 hours to form a preliminary coating film on the surface of the wooden box. Subsequently, the wooden box is moved to an oven and heat-cured at 75 degrees Celsius for 3 hours. During this process, the coating is fully cross-linked to form a strong and dense surface. After the curing is completed, the wooden box is gradually cooled to room temperature in the oven to avoid cracking or peeling of the coating due to rapid cooling. Make sure that the wooden box is completely cooled before taking it out to obtain a high-strength and water-resistant wooden box reinforced with the coating.

[0129] Among them, the multifunctional alcohol curing agent is polyethylene glycol (PEG); the viscosity modifier is ethyl acetate (EA); the plasticizer is dioctyl adipate (DOA); the nano-reinforced filler is aerosil (AS); the particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers; the reinforcing fiber is glass fiber (GF); the leveling agent is polyether block amino silicone oil (Polyether - Block - Amino - Siloxane, PEBAS); defoaming agent: fatty alcohol polyoxyethylene ether (Alkyl Polyglycoside, APG); mildew inhibitor: dodecyl dimethyl benzyl ammonium bromide (Benzalkonium Chloride, BKC).

[0130] Example 5

[0131] Step S1: Preparation of coating components

[0132] 1000 parts by mass of MDI polyurethane prepolymer;

[0133] 750 parts by weight of multifunctional alcohol curing agent;

[0134] 200 parts by mass of viscosity modifier;

[0135] 38 parts by mass of plasticizer;

[0136] 150 parts by mass of nano-reinforced filler;

[0137] 18 parts by mass of reinforcing fiber;

[0138] 8 parts by mass of leveling agent;

[0139] 3 parts by mass of defoamer;

[0140] 4 parts by mass of antifungal agent.

[0141] Step S2: Mixing of paint

[0142] In a clean container, first weigh the polyurethane prepolymer, curing agent and viscosity regulator in proportion and mix them evenly; then add the plasticizer, nano-reinforced filler, leveling agent, defoamer and mildew inhibitor, and stir thoroughly.

[0143] Step S3: Dip coating of wooden box

[0144] Pour the prepared paint into the dipping tank, and then put the wooden box to be treated into the dipping tank, so that the wooden box is completely immersed in the prepared paint, ensuring that every surface of the wooden box is in contact with the paint. The dipping time is 45 seconds to ensure that the surface of the wooden box fully absorbs the paint. During the dipping process, in order to ensure the uniform distribution of the coating, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every 5 seconds, so that the wooden box rotates alternately clockwise and counterclockwise in the dipping tank. When the wooden box is completely lifted from the paint, repeat the dipping action twice to ensure the integrity and uniformity of the coating. After each dipping, gently shake off the excess paint and ensure that the surface of the wooden box is flat and there are no dripping marks.

[0145] Step S4: Curing of coating

[0146] After the dip coating is completed, the wooden box is placed in a well-ventilated environment to dry naturally for 24 hours to form a preliminary coating film on the surface of the wooden box. Subsequently, the wooden box is moved to an oven and heat-cured at 75 degrees Celsius for 3 hours. During this process, the coating is fully cross-linked to form a strong and dense surface. After the curing is completed, the wooden box is gradually cooled to room temperature in the oven to avoid cracking or peeling of the coating due to rapid cooling. Make sure that the wooden box is completely cooled before taking it out to obtain a high-strength and water-resistant wooden box reinforced with the coating.

[0147] Among them, the multifunctional alcohol curing agent is polyethylene glycol (PEG); the viscosity modifier is ethyl acetate (EA); the plasticizer is dioctyl adipate (DOA); the nano-reinforced filler is aerosil (AS); the particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers; the reinforcing fiber is glass fiber (GF); the leveling agent is polyether block amino silicone oil (Polyether - Block - Amino -Siloxane, PEBAS); defoaming agent: fatty alcohol polyoxyethylene ether (Alkyl Polyglycoside, APG); mildew inhibitor: dodecyl dimethyl benzyl ammonium bromide (Benzalkonium Chloride, BKC).

[0148] Example 6

[0149] Step S1: Preparation of coating components

[0150] 1000 parts by mass of MDI polyurethane prepolymer;

[0151] 780 parts by weight of multifunctional alcohol curing agent;

[0152] 280 parts by mass of viscosity modifier;

[0153] 40 parts by mass of plasticizer;

[0154] 140 parts by mass of nano-reinforced filler;

[0155] 12 parts by mass of reinforcing fiber;

[0156] 4 parts by mass of leveling agent;

[0157] 5 parts by mass of defoamer;

[0158] 5 parts by mass of antifungal agent.

[0159] Step S2: Mixing of paint

[0160] In a clean container, first weigh the polyurethane prepolymer, curing agent and viscosity regulator in proportion and mix them evenly; then add the plasticizer, nano-reinforced filler, leveling agent, defoamer and mildew inhibitor, and stir thoroughly.

[0161] Step S3: Dip coating of wooden box

[0162] Pour the prepared paint into the dipping tank, and then put the wooden box to be treated into the dipping tank, so that the wooden box is completely immersed in the prepared paint, ensuring that every surface of the wooden box is in contact with the paint. The dipping time is 45 seconds to ensure that the surface of the wooden box fully absorbs the paint. During the dipping process, in order to ensure the uniform distribution of the coating, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every 5 seconds, so that the wooden box rotates alternately clockwise and counterclockwise in the dipping tank. When the wooden box is completely lifted from the paint, repeat the dipping action twice to ensure the integrity and uniformity of the coating. After each dipping, gently shake off the excess paint and ensure that the surface of the wooden box is flat and there are no dripping marks.

[0163] Step S4: Curing of coating

[0164] After the dip coating is completed, the wooden box is placed in a well-ventilated environment to dry naturally for 24 hours to form a preliminary coating film on the surface of the wooden box. Subsequently, the wooden box is moved to an oven and heat-cured at 75 degrees Celsius for 3 hours. During this process, the coating is fully cross-linked to form a strong and dense surface. After the curing is completed, the wooden box is gradually cooled to room temperature in the oven to avoid cracking or peeling of the coating due to rapid cooling. Make sure that the wooden box is completely cooled before taking it out to obtain a high-strength and water-resistant wooden box reinforced with the coating.

[0165] Among them, the multifunctional alcohol curing agent is polyethylene glycol (PEG); the viscosity modifier is ethyl acetate (EA); the plasticizer is dioctyl adipate (DOA); the nano-reinforced filler is aerosil (AS); the particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers; the reinforcing fiber is glass fiber (GF); the leveling agent is polyether block amino silicone oil (Polyether - Block - Amino - Siloxane, PEBAS); defoaming agent: fatty alcohol polyoxyethylene ether (Alkyl Polyglycoside, APG); mildew inhibitor: dodecyl dimethyl benzyl ammonium bromide (Benzalkonium Chloride, BKC).

[0166] In order to verify the performance improvement of the wooden box after coating treatment in the above embodiment, bending strength test and water contact angle measurement were carried out. A universal material testing machine was used to perform bending tests on the wooden box before and after coating treatment, and the maximum load at break was recorded to calculate the rate of change of bending strength. The contact angle of water droplets on the coating surface was measured by static titration. A certain volume of pure water was dripped onto the coating surface under constant temperature and humidity conditions using a contact angle meter. The angle of contact between the water droplet and the surface was immediately recorded, and the average of five measurements was taken as the measurement result. The rate of change of bending strength and water contact angle of each embodiment are shown in Table 1.

[0167] Table 1 Performance test results

[0168] Example Bending strength change rate Water contact angle Example 1 +53.2％ 145° Example 2 +51.3％ 142° Example 3 +63.8％ 139° Example 4 +58.2％ 143° Example 5 +69.1％ 148° Example 6 +50.9％ 144°

[0169] Through the analysis of the performance test results of the wooden boxes in each embodiment after coating treatment, it can be seen that the coating technology significantly improves the mechanical strength and waterproof properties of the wooden box. As shown in Table 1, the bending strength of the wooden boxes in all embodiments has increased significantly after coating treatment, with a change rate between +50.9% and +69.1%, indicating that the coating not only enhances the structural stability of the wood itself, but also gives the box higher durability and the ability to resist external stress. In addition, the measurement results of the water contact angle show that the coating surface has a high hydrophobicity, with an angle range of 139° to 148°, which is much higher than the natural water contact angle of untreated wood. This shows that the coating effectively prevents water penetration and greatly enhances the waterproof performance of the wooden box. Based on the above data, it can be concluded that the developed nanomaterial coating technology not only effectively improves the mechanical properties of the wooden box, but also provides it with excellent waterproof protection, making the wooden box more durable in practical applications.

[0170] The above embodiments are exemplary, and their purpose is to illustrate the technical concept and features of the present invention so that people familiar with the technology in this field can understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A surface strengthening process for a wooden box based on nano coating, characterized in that: The following steps are involved: a) preparing a coating component comprising a polyurethane prepolymer, a curing agent, a viscosity modifier, a plasticizer, a nano-reinforced filler, a reinforcing fiber, a leveling agent, a defoaming agent and a mildew preventer; b) mixing the above coating components in a container to obtain a dip coating; c) immersing the wooden box to be treated into the prepared coating so that the dip coating adheres to the surface; d) After the coating is initially dried, the coating is cured by heating to obtain a surface-reinforced wooden box.

2. The surface strengthening process of a wooden box based on nano coating according to claim 1 is characterized in that: The coating components include: 1000 parts by mass of MDI polyurethane prepolymer; 600-800 parts by weight of multifunctional alcohol curing agent; 150-350 parts by mass of viscosity modifier; 25-50 parts by weight of plasticizer; 80-200 parts by mass of nano-reinforced filler; 20-40 parts by weight of reinforcing fiber; Leveling agent 5-10 parts by mass; 3-6 parts by mass of defoamer; 3~6 parts by weight of antifungal agent.

3. The surface strengthening process of a wooden box based on nano coating according to claim 2 is characterized in that: The multifunctional alcohol curing agent is selected from any one or more of the following components: polyoxypropylene glycol, polyoxyethylene glycol, polytetramethylene ether glycol, 1,4-butanediol ester glycol, and polycarbonate glycol.

4. The surface strengthening process of a wooden box based on nano coating according to claim 2 is characterized in that: The viscosity modifier is selected from any one or more of the following components: acetone, ethyl acetate, and cyclohexanone.

5. The surface strengthening process of a wooden box based on nano coating according to claim 2 is characterized in that: The plasticizer is selected from any one or more of the following components: dibutyl phthalate, tributyl citrate, and dioctyl adipate.

6. The surface strengthening process of a wooden box based on nano coating according to claim 2 is characterized in that: The nano-reinforced filler is selected from any one or more of the following components: fumed silica, precipitated silica, fused silica, anatase titanium dioxide, and rutile titanium dioxide; the particle size of the nano-reinforced filler is in the range of 50 to 200 nanometers.

7. The surface strengthening process of a wooden box based on nano coating according to claim 2 is characterized in that: The reinforcing fibers are selected from any one or more of the following components: chopped carbon fibers, continuous carbon fibers, carbon nanotubes, and glass fibers.

8. The surface strengthening process of a wooden box based on nano coating according to claim 2 is characterized in that: The leveling agent is selected from any one or more of the following components: polydimethylsiloxane, polyether block amino silicone oil, fluorosilicone; and / or The defoamer is selected from any one or more of the following components: silicone oil, fatty alcohol polyoxyethylene ether, polydimethylsiloxane; and / or The mildew inhibitor is selected from any one or more of the following components: tributyltin hydrochloride, dodecyldimethylbenzylammonium bromide, imidazolinone, and phenoxyethanol.

9. The surface strengthening process for wooden box based on nano coating according to any one of claims 1 to 8, characterized in that: In step c), the prepared coating is poured into a dipping tank, and then the wooden box to be treated is also placed in the dipping tank, so that the opening of the wooden box faces downward and is completely immersed in the prepared coating, and it is ensured that every surface of the wooden box is in contact with the coating; the dipping time is 30 seconds to 60 seconds; during the dipping process, the wooden box is rotated relative to the dipping tank, and the rotation direction of the wooden box is changed every few seconds; during the dipping process, the wooden box is lifted and immersed several times.

10. The surface strengthening process of a wooden box based on nano coating according to any one of claims 1 to 8, characterized in that: In step d), after the dipping is completed, the wooden box is naturally dried for at least 24 hours, and then the wooden box is moved to an oven and heat-cured at 70 to 80 degrees Celsius for 2 to 4 hours.