Protective coating for wood base material as well as preparation method and application of protective coating

Abstract

The invention relates to the field of coatings, in particular to a protective coating for a wood base material as well as a preparation method and application of the protective coating. The protective coating for the wood base material comprises the following raw materials in percentage by mass: 20-40% of a base material, 5-15% of a penetration enhancer, 5-15% of a functional auxiliary agent and 30-60% of a solvent, wherein the base material comprises carboxyl modified acrylic resin and a plant extract; the penetration enhancer comprises alkyl glycoside and polyethylene glycol. All the components of the protective paint provided by the invention have a synergistic effect, so that the unification of deep penetration and multiple protection is realized; the plant extract can enhance the biocompatibility of the coating and wood; the carboxyl modified acrylic resin ensures the bonding strength and the film-forming property of the coating; the penetration enhancer compound system greatly improves the penetration capacity of the coating on wood, and breaks through the limitation that the traditional coating only has surface protection; the multifunctional auxiliaries have a synergistic effect, and various wood degradation factors such as mould erosion, ultraviolet aging and oxidative degradation can be synchronously resisted.

Description

Technical Field

[0001] This invention relates to the field of coatings, and more particularly to a protective coating for wood substrates, its preparation method, and its application. Background Technology

[0002] Wood, as a natural, environmentally friendly material with good processing properties, is widely used in the construction industry. Whether in residential buildings (doors, windows, floors, beams, columns) or public buildings (decorative components), wood is extensively used as a base material. However, as a natural organic material, wood is susceptible to both environmental and biological erosion during long-term service, leading to performance degradation and structural damage, severely impacting the safety, durability, and aesthetics of buildings. Statistics show that over 50% of wooden components used in construction exhibit varying degrees of decay, mold, insect infestation, or UV aging after 3-5 years of use. Therefore, wood protection has become a core issue in the field of building material preservation.

[0003] Currently, the protection of building timber mainly relies on the technical means of applying protective coatings to the surface. The core objective is to form a barrier on the surface of the timber through the coating to block the invasion of moisture, oxygen, ultraviolet light and microorganisms. Existing protective coatings can be divided into three categories according to the type of base material: the first is traditional natural coatings, such as beeswax and tung oil. Although these coatings have good biocompatibility and environmental friendliness, they have defects such as slow curing speed, poor water resistance, and short protective life (usually requiring recoating every 1-2 years). Moreover, they can only adhere to the surface of wood and cannot penetrate deep into the interior to form long-term protection. The second is synthetic resin coatings, such as polyurethane and epoxy resin. These coatings have excellent weather resistance and mechanical properties, but due to their large molecular weight and high viscosity, they have extremely poor permeability and cannot penetrate into the internal structure of aged or porous wood. In addition, some synthetic resins contain volatile toxic solvents (such as toluene and xylene), which can cause secondary damage to the wood itself and the indoor and outdoor environment, failing to meet the environmental protection requirements of modern buildings. The third is inorganic nano-coatings, such as nano-silica sol coatings. Although they have a certain degree of permeability and weather resistance, the interfacial bonding between the coating and the wood is weak, and they are prone to peeling off due to the shrinkage of the wood when it is wet and dry. Furthermore, they have a single function and cannot simultaneously cope with multiple deterioration factors such as mold erosion and ultraviolet aging.

[0004] Further analysis reveals that the core technological bottleneck of existing protective coatings is insufficient permeability. Traditional coatings are mostly surface-sealing types, unable to penetrate deep into the porous structures of building timber, such as vascular bundles and intercellular spaces. This results in the timber still being prone to decay and mold, leading to a "good on the outside, bad on the inside" protective failure phenomenon.

[0005] Therefore, developing a highly permeable deep protective coating for building timber is of great practical significance and application value for solving the technical challenges of protecting building timber and extending the service life of building timber structures. Summary of the Invention

[0006] This invention provides a protective coating for wood substrates, its preparation method, and its application, in order to solve the problem of insufficient permeability of existing protective coatings for wood.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a protective coating for wood substrates, comprising the following raw materials in weight percentages: Base material 20-40%, penetration enhancer 5-15%, functional additives 5-15%, and solvent 30-60%; The base material includes carboxyl-modified acrylic resin and plant extracts; The penetration enhancer includes alkyl glycosides and polyethylene glycol.

[0008] In some specific embodiments, the mass ratio of the modified acrylic resin to the plant extract is (2~5):1.

[0009] In some specific embodiments, the carboxyl content in the carboxyl-modified acrylic resin is 3.5wt% to 6.0wt%.

[0010] In some specific embodiments, the plant extract includes at least one of neem extract, artemisia extract, and camphor leaf extract.

[0011] In some specific embodiments, the neem extract comprises an ethanol-water aqueous extract of neem.

[0012] In some specific embodiments, the mugwort extract includes an ethanol-water aqueous extract of mugwort.

[0013] In some specific embodiments, the camphor tree leaf extract is obtained by supercritical CO2 extraction.

[0014] In some specific embodiments, the mass ratio of the alkyl glycoside to the polyethylene glycol is (1~2):1.

[0015] In some specific embodiments, the number-average molecular weight of the polyethylene glycol is 400 to 1000.

[0016] In some specific embodiments, the functional additives include antifungal agents, ultraviolet absorbers, and antioxidants.

[0017] In some specific embodiments, the mass ratio of the antifungal agent, the ultraviolet absorber, and the antioxidant is (2~4):(1~2):1.

[0018] In some specific embodiments, the antifungal agent includes isothiazolinone and / or bifonazole.

[0019] In some specific embodiments, the ultraviolet absorber includes benzotriazole and / or benzophenone.

[0020] In some specific embodiments, the antioxidants include tea polyphenols and / or vitamin E.

[0021] In some specific embodiments, the solvent includes at least one of ethanol, propylene glycol, and dimethyl ether.

[0022] A second aspect of the present invention also provides a method for preparing the above-mentioned protective coating for wood substrates, comprising the following steps: The base material and solvent are mixed and dispersed in the first stage to obtain a pre-dispersion. The pre-dispersed liquid and functional additives are mixed and then dispersed a second time to obtain a mixed liquid; The mixture and penetration enhancer are combined, a third dispersion is carried out, and then filtered through a filter screen to obtain a protective coating for wood substrates.

[0023] In some specific embodiments, the conditions for the first dispersion are: temperature of 30~40℃, time of 20~40min, and rotation speed of 300~500rpm.

[0024] In some specific embodiments, the conditions for the second dispersion are: temperature of 50~60℃, time of 1~2h, and rotation speed of 500~800r / min.

[0025] In some specific embodiments, the conditions for the third dispersion are: temperature of 20~25℃, time of 30~40min, and rotation speed of 600~800r / min.

[0026] In some specific embodiments, the pore size of the filter screen is 100-200 mesh.

[0027] In some specific embodiments, the process of mixing the pre-dispersion liquid and the functional additive includes: Add the antifungal agent, ultraviolet absorber and antioxidant to the pre-dispersion solution in sequence.

[0028] A third aspect of the present invention also provides the application of the above-described protective coating for wood substrates in wood protection.

[0029] In some specific embodiments, the application includes: A protective coating for wood substrates is applied to the wood surface and then dried to form a protective coating on the wood surface.

[0030] Compared with the prior art, the present invention has the following beneficial effects: (1) The protective coating for wood substrates provided by this invention is composed of a base material, functional additives, solvents, and penetration promoters in a specific mass ratio. Through the synergistic innovation of composite base material design and penetration promoter optimization, the components work synergistically to achieve a unity of deep penetration and multiple protections. Among them, plant extracts can enhance the biocompatibility of the coating with wood; carboxyl-modified acrylic resin ensures the bonding strength and film-forming performance of the coating; the penetration promoter compound system greatly improves the coating's penetration ability into wood, breaking through the limitation of traditional coatings that only provide surface protection; the coating has good compatibility with wood and will not affect the original appearance and core properties of the wood. In addition, the raw materials are low in toxicity and low in VOCs, avoiding secondary damage to the wood itself and the environment, and meeting the requirements of green building materials; (2) The protective coating for wood substrates provided by this invention is prepared using a medium-low temperature and natural drying process after being applied to the wood surface. It does not require high-temperature curing, thus avoiding high-temperature damage to the wood. It is suitable for the processing and protection needs of various building wood components, ensuring good compatibility and consistent appearance between the coating and the wood. Furthermore, the protective coating for wood substrates achieves an adhesion grade of 0 on the wood surface, a salt water immersion time of ≥720h, and a mildew resistance grade of 0. Its penetration depth into the wood is 2~5mm, and it does not obscure the original texture and color of the wood, thus meeting the dual needs of decoration and protection for building wood. It can be widely applied to new construction protection and repair protection scenarios for building wood. Attached Figure Description

[0031] The above and other objects, features, and advantages of the invention will be apparent from the following description of preferred embodiments illustrating the gist of the invention and its use, and the accompanying drawings, in which: Figure 1 This is a photograph of the protective coating for wood substrates applied to pine wood specimens in Example 1. Figure 2 This is a photograph of the protective coating used on wood substrates in Example 1 after it was applied to a cedar wood specimen. Detailed Implementation

[0032] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments described below are for illustrative purposes only and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, conditions and methods known in the art can be used for processing.

[0033] To address the problem of poor permeability of existing wood protective coatings, the following technical solution is provided: This invention provides a protective coating for wood substrates, comprising the following raw materials in weight percentages: Base material 20-40%, penetration enhancer 5-15%, functional additives 5-15%, and solvent 30-60%; The base material includes carboxyl-modified acrylic resin and plant extracts; The penetration enhancer includes alkyl glycosides and polyethylene glycol.

[0034] The protective coating for wood substrates of the present invention is mainly composed of a base material, a penetration enhancer, functional additives, and a solvent in a specific ratio. The base material includes carboxyl-modified acrylic resin and plant extracts. The carboxyl-modified acrylic resin has carboxyl groups on its molecular chain, which can form strong hydrogen bonds with the hydroxyl groups in cellulose and lignin in wood. This molecular-level adsorption allows the carboxyl-modified acrylic resin to adhere tightly to the wood surface and pore walls, preventing it from easily falling off, thus ensuring the coating's adhesion strength and film-forming properties. The plant extracts are homologous to wood, enhancing the biocompatibility of the protective coating for wood substrates with wood. The penetration enhancer is mainly composed of alkyl glycosides and polyethylene glycol. Their synergistic effect significantly reduces the surface tension of the coating, promoting the penetration of the protective coating into the wood's vessels and intercellular spaces, thereby achieving deep protection. The addition of functional additives can meet diverse protection needs for wood. The addition of solvents can adjust the viscosity of the protective coating for wood substrates to suit penetration requirements.

[0035] Therefore, the components in the protective coating for wood substrates provided by this invention work synergistically to achieve a balance between deep penetration and multiple layers of protection, adapting to the processing and protection needs of various building wood components, and ensuring good compatibility and consistent appearance between the coating and the wood.

[0036] In this invention, the term "carboxyl-modified acrylic resin" refers to a polymer in which carboxyl (-COOH) functional groups are introduced into the main chain of an acrylic resin.

[0037] As an example, the mass percentage of the binder in a protective coating for wood substrates can be any one of the following values ​​or a range between any two: 20%, 21%, 23%, 25%, 28%, 30%, 32%, 34%, 35%, 36%, 38%, and 40%.

[0038] As an example, the mass percentage of the penetration enhancer in a protective coating for wood substrates can be any one of the following values ​​or a range between any two: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, and 15%.

[0039] As an example, the mass percentage of functional additives in protective coatings for wood substrates can be any one of the following values ​​or a range between any two: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, and 15%.

[0040] As an example, the mass percentage of solvent in a protective coating for wood substrates can be any one of the following points or a range between any two: 30%, 32%, 34%, 35%, 38%, 40%, 43%, 45%, 47%, 50%, 52%, 55%, 58%, and 60%.

[0041] In some embodiments, the mass ratio of the carboxyl-modified acrylic resin to the plant extract is (2~5):1. As an example, the mass ratio of the modified acrylic resin to the plant extract can be any one of the following values ​​or a range between any two: 2:1, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.3:1, 4.5:1, 4.8:1, and 5:1.

[0042] In this invention, by controlling the mass ratio of carboxyl-modified acrylic resin and plant extract within the aforementioned range, a balance can be achieved in mechanical properties, biocompatibility, and functional synergy between the two. The carboxyl-modified acrylic resin dominates the mechanical basis of the coating, ensuring a continuous and dense protective film after drying through physical entanglement between molecular chains and adsorption by the active carboxyl groups. The plant extract can neutralize the strong polarity of the carboxyl-modified acrylic resin through its own weak polar groups. On one hand, plant extracts contain active ingredients such as terpenes, phenols, and fatty acids. The weak polar groups in their molecular structure, such as alkyl, ether, and ester groups, can neutralize the carboxyl groups of the carboxyl-modified acrylic resin. These weak polar groups can encapsulate the strong polarity sites of the resin molecules, reducing the overall polarity of the resin and preventing excessive adsorption between the coating and the wood pore walls, thus hindering penetration. On the other hand, the neutralized resin polarity is more compatible with the solvent system, further reducing the coating viscosity and assisting the penetration promoter in driving the coating to diffuse deeper into the wood. Meanwhile, the natural organic structure of plant extracts can fill the gaps between resin molecular chains, alleviating the film embrittlement problem caused by the strong polarity of the resin, improving the flexibility of the coating, and strengthening the interfacial bonding stability between the resin and wood through the dual effects of polarity regulation and structural filling. This prevents the coating from cracking or peeling off during the drying and wetting shrinkage of the wood, ultimately achieving a synergistic balance of mechanical properties, penetration efficiency, and interfacial compatibility. If the content of carboxyl-modified acrylic resin is too high and the content of plant extracts is insufficient, the strong polarity in the carboxyl-modified acrylic resin cannot be effectively neutralized, resulting in poor interfacial compatibility between the subsequent coating and the wood, and easy interfacial delamination after coating. If the content of carboxyl-modified acrylic resin is too low and the content of plant extracts is too high, the adhesion strength of the film-forming performance will be insufficient.

[0043] In some embodiments, the plant extract includes, but is not limited to, at least one of neem extract, artemisia extract, and camphor leaf extract.

[0044] In this invention, the extracts of neem, artemisia, and camphor tree leaves not only enhance compatibility with wood but also help improve the anti-mildew effect.

[0045] In some embodiments, the neem extract comprises an ethanol-water aqueous extract of neem.

[0046] In some embodiments, the preparation of neem extract includes: The bark or fruit of the neem tree is mixed with an ethanol solution and then subjected to ultrasonic extraction to obtain a neem extract.

[0047] In some embodiments, the preparation of neem extract specifically includes: The bark or fruit of the chinaberry tree is dried and pulverized in sequence to obtain powder; The powder was placed in an ethanol solution and subjected to ultrasonic extraction to obtain an extract. The extract was filtered to obtain a fine filtrate; The filtrate was concentrated under reduced pressure to a solid content of 20wt%~25wt% to obtain neem extract.

[0048] In some embodiments, the drying temperature for the preparation of neem extract is 60-70°C, and the drying time is 8-12 hours.

[0049] In some embodiments, the particle size of the powder in the preparation of neem extract is 80-100 mesh.

[0050] In some embodiments, the concentration of the ethanol solution in the preparation of the neem extract is 70wt%~80wt%.

[0051] In some embodiments, in the preparation of neem extract, the ratio of powder to ethanol solution is 1g:(8~12)mL.

[0052] In some embodiments, the ultrasonic extraction conditions in the preparation of neem extract are: power of 300-500W and time of 40-60min.

[0053] In some embodiments, the specific process of filtration and separation in the preparation of neem extract includes: firstly, coarsely filtering the extract through a 200-mesh filter cloth to remove undissolved raw material residues; then, finely filtering the filtrate through a 0.45μm microporous membrane to remove macromolecular impurities (such as polysaccharides and cellulose fragments) to avoid agglomeration when mixed with modified acrylic resin in the subsequent process.

[0054] In some embodiments, the conditions for vacuum concentration in the preparation of neem extract are: vacuum degree of 0.08~0.09MPa and temperature of 50~55℃.

[0055] In some embodiments, the mugwort extract comprises an aqueous ethanol extract of mugwort.

[0056] In some embodiments, the preparation of Artemisia argyi extract includes: Artemisia argyi was mixed with an ethanol solution and refluxed to extract the Artemisia argyi extract.

[0057] In some embodiments, the preparation of Artemisia argyi extract specifically includes: Artemisia argyi was dried and pulverized in sequence to obtain powder; The powder was placed in an ethanol solution and heated to boiling point for reflux extraction to obtain the extract. The extract was centrifuged to obtain a fine filtrate; The filtrate was spray-dried to obtain Artemisia argyi extract.

[0058] In some embodiments, the drying temperature for Artemisia argyi extract is 50-60°C, and the drying time is 8-12 hours.

[0059] In some embodiments, the particle size of the powder in the preparation of Artemisia argyi extract is 60-80 mesh.

[0060] In some embodiments, the concentration of the ethanol solution in the preparation of Artemisia argyi extract is 60wt%~70wt%.

[0061] In some embodiments, in the preparation of Artemisia argyi extract, the ratio of powder to ethanol solution is 1g:(10~15)mL.

[0062] In some embodiments, the reflux time in the preparation of Artemisia argyi extract is 90-120 min.

[0063] In some embodiments, the reflux extraction is performed ≥2 times during the preparation of Artemisia argyi extract.

[0064] In some embodiments, the reflux extraction process in the preparation of Artemisia argyi extract includes: The powder was placed in an ethanol solution and heated to boiling, then refluxed for extraction twice, each time for 90-120 minutes. After the first extraction, the mixture was filtered, and the residue was added to a fresh mixed solvent for a second extraction. The two filtrates were combined. In some embodiments, the centrifugation conditions in the preparation of Artemisia argyi extract are: a rotation speed of 3000~4000 r / min and a time of 15~20 min.

[0065] In this invention, the purpose of centrifugation in the preparation of Artemisia argyi extract is to remove suspended fine impurity particles.

[0066] In some embodiments, the camphor tree leaf extract is obtained by supercritical CO2 extraction.

[0067] In some embodiments, the preparation of camphor leaf extract includes: Camphor tree leaves were subjected to supercritical CO2 extraction to obtain camphor tree leaf extract.

[0068] In some embodiments, the preparation of camphor leaf extract specifically includes: The camphor tree leaves were dried and crushed in sequence to obtain a powder of 50-70 mesh. The powder and supercritical CO2 are mixed and placed in a supercritical extraction vessel for extraction. After extraction, the supercritical CO2 and the extract are separated into layers. The lower layer of extract is collected to obtain the extract. The extract was filtered and separated to obtain camphor tree leaf extract.

[0069] In some embodiments, in the preparation of camphor tree leaf extract, the ratio of powder to supercritical CO2 is 1g:8~12mL.

[0070] In some embodiments, during the preparation of camphor leaf extract, 8% to 9% by weight of ethanol is added to the supercritical CO2.

[0071] In some embodiments, the conditions for supercritical CO2 extraction in the preparation of camphor tree leaf extract are: pressure of 20-25 MPa, temperature of 40-45°C, and time of 120-150 min.

[0072] In some embodiments, the separation conditions in the preparation of camphor tree leaf extract are: pressure of 5-8 MPa and temperature of 35-40°C.

[0073] In some embodiments, the specific conditions for filtration separation in the preparation of camphor tree leaf extract are as follows: filtration through a 0.22 μm microporous membrane to remove trace amounts of solid impurities.

[0074] In some embodiments, the mass ratio of the alkyl glycoside to the polyethylene glycol is (1~2):1. As an example, the mass ratio of the alkyl glycoside to the polyethylene glycol can be any one of the following values ​​or a range between any two: 1:1, 1.1:1, 1.2:1, 1.4:1, 1.5:1, 1.6:1, 1.8:1, and 2:1.

[0075] In this invention, alkyl glycosides can disperse trace amounts of adhesive in the pores of wood through surface activity, preventing them from clogging the channels; while polyethylene glycol can wrap the adhesive particles and deliver them to the edge of the pores through the flexible entanglement of molecular chains. The two work together to eliminate physical barriers in the penetration path, ensuring that the coating can continue to penetrate deeper, thereby achieving deep protection.

[0076] In some embodiments, the alkyl glycoside comprises an alkyl glycoside with a carbon chain length of C8 to C12.

[0077] As examples, alkyl glycosides include APG1012, APG0810, or APG1214.

[0078] In some embodiments, the number-average molecular weight of the polyethylene glycol is 400 to 1000. As an example, the number-average molecular weight of the polyethylene glycol can be any one of 400, 500, 600, 700, 800, 900 and 1000 or a range between any two.

[0079] In some embodiments, the functional additives include antifungal agents, ultraviolet absorbers, and antioxidants.

[0080] In this invention, the functional additives include antifungal agents, ultraviolet absorbers, and antioxidants. The antifungal agents can effectively inhibit the growth of mold, the ultraviolet absorbers can block the degradation of wood by ultraviolet light, and the antioxidants can delay the oxidative aging of wood. The combination of the three can achieve multiple protections of "antifungal-ultraviolet-antioxidant", thereby meeting the diverse protection needs of wood in different usage environments.

[0081] In some embodiments, the mass ratio of the antifungal agent, the ultraviolet absorber, and the antioxidant is (2~4):(1~2):1. As an example, the mass ratio of the antifungal agent, the ultraviolet absorber, and the antioxidant can be any one of the following values ​​or a range between any two: 2:1:1, 2.2:1.2:1, 2.5:1.5:1, 2.8:1.8:1, 2:2:1, 2:1.8:1, 2:1.5:1, 2:1.2:1, 2:2:1, 3:1:1, and 4:2:1.

[0082] In some embodiments, the antifungal agent includes, but is not limited to, isothiazolinone and / or bifonazole.

[0083] In some embodiments, the ultraviolet absorber includes, but is not limited to, benzotriazole and / or benzophenone.

[0084] In some embodiments, the antioxidants include, but are not limited to, tea polyphenols and / or vitamin E.

[0085] In this invention, the multifunctional additives work synergistically to simultaneously resist various factors that degrade wood, such as mold erosion, ultraviolet aging, and oxidative degradation.

[0086] In some embodiments, the solvent includes, but is not limited to, at least one of ethanol, propylene glycol, and dimethyl ether.

[0087] A second aspect of the present invention also provides a method for preparing the above-mentioned protective coating for wood substrates, comprising the following steps: The base material and solvent are mixed and dispersed in the first stage to obtain a pre-dispersion. The pre-dispersed liquid and functional additives are mixed and then dispersed a second time to obtain a mixed liquid; The mixture and penetration enhancer are combined, a third dispersion is carried out, and then filtered through a filter screen to obtain a protective coating for wood substrates.

[0088] In some embodiments, the conditions for the first dispersion are: temperature of 30~40°C, time of 20~40 min, and rotation speed of 300~500 rpm. As an example, the temperature for the first dispersion can be any one of 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 38°C, 39°C, and 40°C, or a range between any two; the time for the first dispersion can be any one of 20 min, 22 min, 25 min, 26 min, 28 min, 30 min, 32 min, 35 min, 38 min, and 40 min, or a range between any two; and the rotation speed for the first dispersion can be any one of 300 rpm, 320 rpm, 350 rpm, 380 rpm, 400 rpm, 430 rpm, 450 rpm, 470 rpm, and 500 rpm, or a range between any two.

[0089] In some embodiments, the conditions for the second dispersion are: a temperature of 50-60°C, a time of 1-2 hours, and a rotation speed of 500-800 r / min. As an example, the temperature for the second dispersion can be any one of 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, and 60°C, or a range between any two; the time for the second dispersion can be any one of 1 hour, 1.25 hours, 1.5 hours, 1.75 hours, and 2 hours, or a range between any two; and the rotation speed for the second dispersion can be any one of 500 r / min, 520 r / min, 550 r / min, 600 r / min, 650 r / min, 680 r / min, 700 r / min, 750 r / min, and 800 r / min, or a range between any two.

[0090] In some embodiments, the conditions for the third dispersion are: temperature of 20~25°C, time of 30~40 min, and rotation speed of 600~800 r / min. As an example, the temperature for the third dispersion can be any one of 20°C, 21°C, 22°C, 23°C, 24°C, and 25°C, or a range between any two; the time for the third dispersion can be any one of 35 min, 36 min, 37 min, 38 min, 39 min, and 40 min, or a range between any two; and the rotation speed for the third dispersion can be any one of 600 r / min, 650 r / min, 700 r / min, 750 r / min, and 800 r / min, or a range between any two.

[0091] In some embodiments, the pore size of the filter screen is 100 to 200 mesh. As an example, the pore size of the filter screen can be any one of 100 mesh, 110 mesh, 120 mesh, 130 mesh, 140 mesh, 150 mesh, 160 mesh, 170 mesh, 180 mesh, 190 mesh, and 200 mesh, or a range between any two.

[0092] In some embodiments, the process of mixing the pre-dispersion liquid and the functional additive includes: Add the antifungal agent, ultraviolet absorber and antioxidant to the pre-dispersion solution in sequence.

[0093] In this invention, by adding the stabilizing antifungal agent first, followed by the sensitive components UV absorber and antioxidant, the loss of sensitive components during the mixing process can be reduced. Adding the antioxidant first will cause it to degrade prematurely during subsequent stirring, resulting in a decrease in the coating's antioxidant performance.

[0094] A third aspect of the present invention also provides the application of the above-described protective coating for wood substrates in wood protection.

[0095] In some embodiments, the application includes: A protective coating for wood substrates is applied to the wood surface and then dried to form a protective coating on the wood surface.

[0096] In this invention, the coating method is not limited, and any conventional coating method in the art can be used to apply the protective coating for the wood substrate to the wood surface, such as brushing or spraying.

[0097] In some embodiments, the coating thickness is 50-150 μm. As an example, the coating thickness can be any one of 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, and 150 μm, or a range between any two.

[0098] In this invention, by adjusting the coating thickness within the aforementioned range, it is beneficial to... In some embodiments, the drying temperature is 20~30°C, and the drying time is 24~48h. As an example, the drying temperature can be any one of 20°C, 22°C, 24°C, 25°C, 26°C, 28°C, and 30°C, or a range between any two, and the drying time can be any one of 24h, 25h, 28h, 30h, 35h, 36h, 40h, 42h, 45h, and 48h, or a range between any two.

[0099] In some embodiments, the timber includes, but is not limited to, building timber components; optionally, building timber components include, but are not limited to, at least one of beams, columns, brackets, doors, windows, and timber.

[0100] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0101] In the following examples and comparative examples, the neem extract, artemisia extract, and camphor leaf extract were prepared in the following ways.

[0102] The preparation of neem extract includes: Fresh neem bark free from mold and insect infestation is washed, cut into 1-2cm pieces, and dried in a 65℃ constant temperature forced-air drying oven for 12 hours; after drying, it is pulverized into 80-100 mesh neem powder using a high-speed pulverizer. The ratio of neem powder to ethanol solution is 1g:8mL. Neem powder is added to 75wt% ethanol solution, stirred evenly, and then transferred to an ultrasonic extraction vessel. Extraction is carried out at 400W power for 50min. After extraction, the resulting extract is first coarsely filtered through a 200-mesh filter cloth; then the resulting filtrate is finely filtered through a 0.45μm microporous membrane to obtain a fine filtrate. The filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at a vacuum of 0.08 MPa and a water bath temperature of 50 °C until the solid content was 20 wt%, thus obtaining the neem extract.

[0103] The preparation of Artemisia argyi extract includes: Select fresh mugwort before its flowering period, remove the roots and withered leaves, wash it and cut it into 3-5cm sections, place it in a 50℃ constant temperature drying oven and dry for 8 hours; after drying, pulverize it into 60-80 mesh mugwort powder.

[0104] The ratio of Artemisia argyi powder to ethanol solution is 1g:15mL. Add Artemisia argyi powder to 65wt% ethanol solution, transfer to an extraction tank equipped with a reflux condenser, heat to a gentle boil, and maintain reflux extraction twice, each time for 90min. After the first extraction, filter, add fresh mixed solvent to the filter residue for a second extraction, and combine the two filtrates. The combined filtrates were transferred to a high-speed centrifuge and centrifuged at 3500 r / min for 20 min to obtain the crude extract.

[0105] The crude extract was dried using a spray dryer (inlet temperature 180℃, outlet temperature 80℃) to obtain Artemisia argyi extract.

[0106] The preparation of camphor tree leaf extract includes: Select fresh camphor tree leaves, wash them, remove the petioles, and place them in a cool, ventilated place to air dry naturally; then crush the dried camphor tree leaves into 50-70 mesh to obtain camphor tree leaf powder.

[0107] The camphor leaf powder and supercritical CO2 (with 5 wt% ethanol added by weight of supercritical CO2) were used in a ratio of 1 g: 10 mL. The mixture was then transferred to a supercritical CO2 extraction vessel, and the extraction pressure was set to 25 MPa, the extraction temperature to 40 °C, and the extraction time to 150 min. At the same time, the separation vessel pressure was set to 5 MPa and the temperature to 35 °C. The supercritical CO2 and the extract were separated into layers, and the lower layer of extract was collected. The camphor tree leaf extract collected in the separation vessel was filtered through a 0.22 μm microporous membrane to remove trace solid impurities, thus obtaining the camphor tree leaf extract.

[0108] Example 1 Protective coatings for wood substrates are made from raw materials in the mass percentages shown in Table 1; Table 1. Raw material composition of the protective coating for wood substrates in Example 1.

[0109] The preparation of a protective coating for wood substrates includes the following steps: (1) Mix carboxyl-modified acrylic resin with neem extract, add ethanol, place in a high-speed disperser with a constant temperature jacket, stir at 35°C and 400 r / min for 30 min to obtain a pre-dispersion; (2) First, add isothiazolinone to the pre-dispersion liquid and stir at 450 r / min for 12 min; then add benzotriazole and stir at 550 r / min for 12 min; finally add tea polyphenols; heat to 55℃ and stir at 700 r / min for 1.5 h to obtain the mixture. (3) Add alkyl glycosides and polyethylene glycol to the mixture, cool to 22°C, stir at 650 r / min for 30 min; filter through a 150 mesh screen to obtain a protective coating for wood substrates.

[0110] The protective coating for wood substrates described in Example 1 was applied to the surface of a pine specimen (100mm × 100mm × 20mm) using a brush, with a coating thickness of 100μm. After natural drying at 25℃ for 36 hours, the coating was as follows: Figure 1 As shown, the performance was then tested, and the results are as follows: The penetration depth was 3.8 mm; Adhesion rating: 0 (test standard is GB / T9286-1998); UV aging resistance: Grade I (test standard is GB / T1865-2009); Salt water immersion resistance: no bubbling or peeling after 750 hours (test standard is GB / T1763-1989); Mildew resistance rating: Level 0 (testing standard is GB / T1741-2020); VOC content: 4.8g / L (test standard is GB18582-2020); Antioxidant properties: The growth rate of carbonyl value in wood decreased by 66% (compared to uncoated pine specimens).

[0111] Example 2 Protective coatings for wood substrates are made from raw materials in the mass percentages shown in Table 2; Table 2. Raw material composition of the protective coating for wood substrates in Example 2.

[0112] The preparation of a protective coating for wood substrates includes the following steps: (1) Mix carboxyl-modified acrylic resin, Artemisia argyi extract and camphor tree leaf extract, add ethanol and propylene glycol methyl ether, stir at 30°C and 500 r / min for 25 min to obtain a pre-dispersion; (2) Add isothiazolinone to the pre-dispersion solution first, stir at 450 r / min for 10 min, then add benzotriazole, stir at 550 r / min for 10 min, and finally add vitamin E; heat to 60℃, keep warm and stir at 800 r / min for 1 h to obtain the mixture; (3) Add alkyl glycosides and polyethylene glycol to the mixture, cool to 20°C, stir at 650 r / min for 30 min; filter through a 200 mesh screen to obtain a protective coating for wood substrates.

[0113] The protective coating for wood substrates described in Example 2 was applied by spraying to the surface of a cedar specimen (100mm × 100mm × 20mm) to a thickness of 80μm. After natural drying at 30℃ for 24 hours, as shown... Figure 2 As shown, the performance was then tested, and the results are as follows: The penetration depth was 2.8 mm; Adhesion rating: 0 (test standard is GB / T9286-1998); UV aging resistance: No cracking or discoloration after 1000h irradiation (GB / T1865-2009). Salt water immersion resistance: no bubbling or peeling after 750 hours (test standard is GB / T1763-1989); Mildew resistance rating: Level 0 (testing standard is GB / T1741-2020); VOC content: 32g / L (test standard is GB18582-2020); Antioxidant properties: The growth rate of carbonyl value in wood decreased by 65% ​​(compared to uncoated cedar specimens).

[0114] Example 3 Protective coatings for wood substrates are made from raw materials in the mass percentages shown in Table 3; Table 3. Raw material composition of the protective coating for wood substrates in Example 3.

[0115] The preparation of the above-mentioned protective coating for wood substrates includes: (1) Mix carboxyl-modified acrylic resin with neem extract, add ethanol, stir at 40°C and 300 r / min for 40 min to obtain a pre-dispersion; (2) Add isothiazolinone to the pre-dispersion solution first, stir at 450 r / min for 15 min, then add benzotriazole and stir at 550 r / min for 15 min, and finally add tea polyphenols; heat to 50℃, keep warm and stir at 500 r / min for 2 h to obtain the mixture; (3) Add alkyl glycoside and polyethylene glycol (1000) to the mixture, cool to 25°C, stir at 650 r / min for 30 min; filter through a 100 mesh screen to obtain a protective coating for wood substrates.

[0116] The protective coating for wood substrates described in Example 3 was applied to the surface of poplar specimens (100mm×100mm×20mm) by brushing, with a coating thickness of 120μm. After natural drying at 20℃ for 48 hours, the performance was tested, and the results are as follows: The penetration depth was 2.3 mm; Adhesion rating: 0 (test standard is GB / T9286-1998); UV aging resistance: No cracking or discoloration after 2000h irradiation, color difference ΔE≤1.5 (test standard is GB / T1865-2009); Salt water immersion resistance: no bubbling or peeling after 720 hours (test standard is GB / T1763-1989); Mildew resistance rating: Level 0; (Testing standard is GB / T1741-2020); VOC content: 28g / L (test standard is GB18582-2020); Antioxidant properties: The growth rate of carbonyl value in wood decreased by 65%-70% (compared with uncoated poplar specimens).

[0117] Comparative Example 1 Protective coatings for wood substrates are made from raw materials in the mass percentages shown in Table 4; Table 4. Raw material composition of the protective coating used on wood substrates in Comparative Example 1

[0118] The preparation method of the above-mentioned protective coating for wood substrates is the same as that in Example 1.

[0119] The protective coating used in Comparative Example 1 for wood substrates was applied to the surface of pine specimens (100mm×100mm×20mm) by brushing, with a coating thickness of 100μm. After drying at 25℃ for 36 hours, the performance was tested, and the results are as follows: The penetration depth is 3.0 mm; Adhesion rating: Level 3 (test standard is GB / T9286-1998); UV aging resistance (1000h): Complete powdering (test standard is GB / T1865-2009); Salt water immersion resistance: blistering and localized peeling occurred after 240 hours (test standard is GB / T1763-1989). Mildew resistance rating: Level 3 (testing standard is GB / T1741-2020); VOC content: 5.2g / L (test standard is GB18582-2020); Antioxidant properties: The rate of increase in carbonyl value of wood decreased by 22% (compared to uncoated pine specimens).

[0120] Comparative Example 2 Protective coatings for wood substrates are made from raw materials in the mass percentages shown in Table 5. Table 5. Raw material composition of the protective coating used on wood substrates in Comparative Example 2.

[0121] The preparation method of the protective coating for wood substrate described above is the same as that in Example 2.

[0122] The protective coating for wood substrates in Comparative Example 2 was applied to the surface of pine specimens (100mm×100mm×20mm) by brushing, with a coating thickness of 100μm. After drying at 25℃ for 36 hours, the performance was tested, and the results are as follows: The penetration depth is 2.5 mm; Adhesion rating: Level 2 (test standard is GB / T9286-1998); UV aging resistance (1000h): Complete powdering (test standard is GB / T1865-2009); Salt water immersion resistance: 240 (test standard is GB / T1763-1989); Mildew resistance rating: Level 3 (testing standard is GB / T1741-2020); VOC content: 6.0g / L (test standard is GB18582-2020); Antioxidant properties: The growth rate of carbonyl value in wood decreased by 15% (compared to uncoated pine specimens).

[0123] Comparative Example 3 Protective coatings for wood substrates are made from raw materials in the mass percentages shown in Table 6; Table 6 shows the raw material composition of the protective coating used on wood substrates in Comparative Example 3.

[0124] The preparation method of the protective coating for wood substrate in Comparative Example 3 is the same as that in Example 1.

[0125] The protective coating for wood substrates in Comparative Example 3 was applied to the surface of pine specimens (100mm×100mm×20mm) by brushing, with a coating thickness of 100μm. After drying at 25℃ for 36 hours, the performance was tested, and the results are as follows: The penetration depth was 2.2 mm; Adhesion rating: 3 (test standard is GB / T9286-1998); UV aging resistance: 1000h, chalking grade 2, color difference ΔE*ab=4.5, fine cracks appear at the edges (test standard is GB / T1865-2009). Salt water immersion resistance: Localized blistering and adhesion reduced to level 4 after 360 hours (test standard is GB / T1763-1989). Anti-mold rating: Level 1 (localized small amount of mold, coverage area <10%) (test standard is GB / T1741-2020); VOC content: 48g / L (test standard is GB18582-2020); Antioxidant properties: The growth rate of carbonyl value in wood decreased by 30% (compared to uncoated pine specimens).

[0126] Comparative Example 4 Protective coatings for wood substrates are made from raw materials in the percentages by mass shown in Table 7; Table 7 shows the raw material composition of the protective coatings used on wood substrates in Comparative Example 4.

[0127] The preparation method of the protective coating for wood substrate in Comparative Example 4 is the same as that in Example 1.

[0128] The protective coating for wood substrates in Comparative Example 4 was applied to the surface of pine specimens (100mm×100mm×20mm) by brushing, with a coating thickness of 100μm. After drying at 25℃ for 36 hours, the performance was tested, and the results are as follows: The penetration depth is 2.0 mm; Adhesion rating: Level 2 (test standard is GB / T9286-1998); UV aging resistance: chalking grade 3, color difference ΔE*ab=5.2, localized coating peeling (test standard is GB / T1865-2009). Salt water immersion resistance: After 480 hours, large-area blistering occurred and the adhesion dropped to level 4 (test standard is GB / T1763-1989). Mildew resistance rating: Level 2 (testing standard is GB / T1741-2020); VOC content: 5.0g / L (test standard is GB18582-2020); Antioxidant properties: The rate of increase in carbonyl value of wood decreased by 22% (compared to uncoated pine specimens).

[0129] Comparative Example 5 Protective coatings for wood substrates are made from raw materials in the mass percentages shown in Table 8; Table 8 shows the raw material composition of the protective coatings used on wood substrates in Comparative Example 5.

[0130] The preparation method of the protective coating for wood substrate in Comparative Example 5 is the same as that in Example 1.

[0131] The protective coating for wood substrates in Comparative Example 5 was applied to the surface of pine specimens (100mm×100mm×20mm) by brushing, with a coating thickness of 100μm. After drying at 25℃ for 36 hours, the performance was tested, and the results are as follows: The penetration depth was 1.8 mm; Adhesion rating: Level 2 (test standard is GB / T9286-1998); UV aging resistance: 18% (test standard is GB / T1865-2009); Salt water immersion resistance: blistering and localized peeling occurred after 420 hours (test standard is GB / T1763-1989). Mildew resistance rating: Level 2 (testing standard is GB / T1741-2020); VOC content: 4.9g / L (test standard is GB18582-2020); Antioxidant properties: The rate of increase in carbonyl value of wood decreased by 18% (compared to uncoated pine specimens).

[0132] Comparative Example 6 Protective coatings for wood substrates are made from raw materials in the mass percentages shown in Table 9; Table 9 shows the raw material composition of the protective coatings used on wood substrates in Comparative Example 6.

[0133] The preparation method of the protective coating for wood substrate in Comparative Example 6 is the same as that in Example 1.

[0134] The protective coating for wood substrates in Comparative Example 6 was applied to the surface of pine specimens (100mm×100mm×20mm) by brushing, with a coating thickness of 100μm. After drying at 25℃ for 36 hours, the performance was tested, and the results are as follows: The penetration depth was 1.6 mm; Adhesion rating: Level 3 (test standard is GB / T9286-1998); UV aging resistance: After 1000h, the chalking level is 2, the color difference ΔE*ab=4.2, and the edge is slightly cracked (test standard is GB / T1865-2009). Salt water immersion resistance: Localized blistering and adhesion reduced to level 4 after 380 hours (test standard is GB / T1763-1989). Mildew resistance rating: Level 2 (testing standard is GB / T1741-2020); VOC content: 4.7g / L (test standard is GB18582-2020); Antioxidant properties: The rate of increase in carbonyl value of wood decreased by 28% (compared to uncoated pine specimens).

[0135] In summary, by precisely defining the raw material ratio and component selection, this invention achieves a synergistic effect of high penetration, multifunctionality, and high compatibility. Any deviation from the claims will result in a significant decrease in performance, fully demonstrating the scientific nature and necessity of the technical solution of this invention.

[0136] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.

Claims

1. A protective coating for wood substrates, characterized in that, Raw materials including the following mass percentages: Base material 20-40%, penetration enhancer 5-15%, functional additives 5-15%, and solvent 30-60%; The base material includes carboxyl-modified acrylic resin and plant extracts; The penetration enhancer includes alkyl glycosides and polyethylene glycol.

2. The protective coating for wood substrates according to claim 1, characterized in that, The mass ratio of the carboxyl-modified acrylic resin to the plant extract is (2~5):1; The carboxyl content in the carboxyl-modified acrylic resin is 3.5wt%~6.0wt%. The plant extracts include at least one of neem extract, artemisia extract, and camphor leaf extract.

3. The protective coating for wood substrates according to claim 2, characterized in that, The neem extract includes an ethanol-water aqueous extract of neem; The mugwort extract includes an ethanol-water aqueous extract of mugwort; The camphor tree leaf extract was obtained by supercritical CO2 extraction.

4. The protective coating for wood substrates according to claim 1, characterized in that, The mass ratio of the alkyl glycoside to the polyethylene glycol is (1~2):1; The number average molecular weight of the polyethylene glycol is 400-1000.

5. The protective coating for wood substrates according to claim 1, characterized in that, The functional additives include antifungal agents, ultraviolet absorbers, and antioxidants; The mass ratio of the antifungal agent, the ultraviolet absorber, and the antioxidant is (2~4):(1~2):1; The antifungal additives include isothiazolinone and / or bifonazole; The ultraviolet absorber includes benzotriazole and / or benzophenone; The antioxidants include tea polyphenols and / or vitamin E.

6. The protective coating for wood substrates according to claim 1, characterized in that, The solvent includes at least one of ethanol, propylene glycol, and dimethyl ether.

7. A method for preparing a protective coating for wood substrate according to any one of claims 1 to 6, characterized in that, Includes the following steps: The base material and solvent are mixed and dispersed in the first stage to obtain a pre-dispersion. The pre-dispersed liquid and functional additives are mixed and then dispersed a second time to obtain a mixed liquid; The mixture and penetration enhancer are combined, a third dispersion is carried out, and then filtered through a filter screen to obtain a protective coating for wood substrates.

8. The method for preparing a protective coating for wood substrates according to claim 7, characterized in that, The conditions for the first dispersion were: temperature 30~40℃, time 20~40min, and rotation speed 300~500rpm; The conditions for the second dispersion are: temperature 50~60℃, time 1~2h, and rotation speed 500~800r / min; The conditions for the third dispersion are: temperature 20~25℃, time 30~40min, and rotation speed 600~800r / min; The filter screen has a pore size of 100-200 mesh.

9. The method for preparing a protective coating for wood substrates according to claim 7, characterized in that, The process of mixing the pre-dispersion liquid and the functional additives includes: Add the antifungal agent, ultraviolet absorber and antioxidant to the pre-dispersion solution in sequence.

10. The application of the protective coating for wood substrates according to any one of claims 1 to 6 in wood protection.

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