Stabilizing treatment process for wooden pipe body of woodwind instrument

Abstract

The invention provides a stabilizing treatment process for a wooden pipe body of a woodwind instrument, and relates to the technical field of musical instrument manufacturing and wood modification. According to the process, hemicellulose is subjected to precise enzymolysis through xylanase / mannase, and hydrophobic alkenyl is grafted to reduce hygroscopicity; carrying out vacuum pressure impregnation by using double resin liquid to form a flexible interface layer and a high-modulus functional body layer; and finally, constructing a gradient modulus composite structure through curing such as gradient temperature rise. According to the invention, collaborative optimization of size stability, mechanical enhancement and acoustic retention of the pipe body is realized, hydrophobic and oleophobic properties and antibacterial and wear-resistant properties are achieved, and the problem that size stability and acoustic performance are difficult to consider in the traditional process is solved.

Description

Technical Field

[0001] This invention relates to the field of musical instrument manufacturing and wood modification technology, specifically to a stabilization treatment process for the wooden tubes of a woodwind musical instrument. Background Technology

[0002] Woodwind instruments (such as clarinets and flutes) are often made of hardwoods like ebony and mahogany, which, due to their dense grain and excellent acoustic conductivity, impart a rich and full tone. However, natural wood is rich in hydroxyl groups, making it prone to shrinkage and swelling with changes in temperature and humidity. This can lead to warping and cracking of the instrument body, severely affecting its intonation stability and lifespan. Therefore, stabilization treatment of woodwind instruments is a key technology in the instrument manufacturing industry.

[0003] Existing wood stabilization technologies mainly include physical and chemical methods. Physical methods, such as vacuum pressure impregnation, improve dimensional stability by filling the wood cell cavities with resin. However, the poor compatibility between the resin and cell wall interface leads to stress concentration after curing, and uneven filling can reduce the wood's vibration transmission performance, resulting in a muffled tone and reduced sensitivity. Chemical methods, such as acetylation, reduce hygroscopicity through the reaction of acid anhydrides with hydroxyl groups. However, the reaction process easily produces acidic byproducts, which may cause cellulose degradation. Furthermore, indiscriminate modification can damage the acoustic framework of the wood, making it difficult to simultaneously achieve optimal acoustic performance.

[0004] Existing technologies are mostly designed to enhance the mechanical properties of building materials, without fully considering the special acoustic requirements of musical instrument wood, and lack processing techniques that can simultaneously achieve dimensional stability and acoustic preservation.

[0005] Therefore, there is an urgent need to develop a stabilization method specifically for woodwind instrument wood that can effectively suppress moisture absorption and deformation while preserving or even optimizing its natural acoustic properties to the maximum extent. Summary of the Invention

[0006] To improve the dimensional stability and acoustic performance compatibility of woodwind instrument bodies, this invention provides a stabilization process for woodwind instrument bodies. This process combines selective modification with hemicellulase and C6-C18 alkenyl succinic anhydride, gradient double-resin liquid vacuum pressure impregnation, and gradient temperature curing. This reduces the hygroscopicity of the wood at its source while preserving the natural acoustic framework, constructing a gradient modulus composite structure to eliminate interfacial stress, and achieving synergistic optimization of dimensional stability, durability, and acoustic performance.

[0007] One objective of this invention is to provide a stabilization treatment process for the wooden body of a woodwind musical instrument, comprising the following steps: S1. The wooden tube blank is subjected to hemicellulase treatment and C6~C18 alkenyl succinic anhydride treatment in sequence to obtain the first blank; S2. The first blank is first impregnated with the first resin liquid and then pre-cured to obtain the second blank; S3. Impregnate the second blank with the second resin solution to obtain the third blank; S4. The third blank is cured to obtain a stabilized wooden tube for a woodwind instrument. The first resin liquid comprises an epoxy resin with an epoxy equivalent of 180-220 and a hydroxyl-terminated polyurethane prepolymer; The second resin liquid includes epoxy resin, polyurethane prepolymer, nanocellulose whiskers, and hydroxyl-terminated polydimethylsiloxane.

[0008] Preferably, the hemicellulase in step S1 includes xylanase and / or mannanase.

[0009] Preferably, the curing process in step S4 includes a gradient temperature curing process: first drying at 60~70℃ for 4~6 hours, then drying at 80~90℃ for 2~4 hours, and finally drying at 100~110℃ for 2~3 hours, with a heating rate ≤5℃ / h.

[0010] Preferably, before the gradient temperature curing process in step S4, the third blank is air-dried naturally for 24 to 48 hours.

[0011] Preferably, the step S1 of sequentially treating the wooden tube blank with hemicellulase and C6-C18 alkenyl succinic anhydride includes: The wooden tube blank is placed in a reaction vessel and soaked in a hemicellulase solution for 1 to 3 hours. The concentration of the hemicellulase solution is 0.5% to 2%, the pH value is 5.0 to 6.0, and the temperature is 40 to 50°C. After draining the hemicellulase solution and washing with deionized water, an organic solution containing C6-C18 alkenyl succinic anhydride is injected and reacted for 2-5 hours. The mass fraction of the C6-C18 alkenyl succinic anhydride is 5%-15%, and the reaction temperature is 50-70℃. After the reaction is complete, the residual liquid is discharged, washed with ethanol, and dried at 55-65℃ until the water content is 10%-15%.

[0012] Preferably, the organic solution containing C6-C18 alkenyl succinic anhydride further includes a catalyst; The catalyst comprises at least one of 4-dimethylaminopyridine, triethylamine, anhydrous sodium carbonate, or dicyclohexylcarbodiimide (DCC).

[0013] Preferably, the first resin liquid impregnation in step S2 includes: evacuating to -0.08 to -0.1 MPa and maintaining for 30 to 40 minutes, injecting the first resin liquid and immersing under vacuum for 2 to 4 hours, and then pressurizing to 0.3 to 0.5 MPa and maintaining for 2 to 3 hours; The pre-curing conditions are 60~80℃ for 1~2 hours.

[0014] Preferably, the impregnation of the second resin liquid in step S3 includes: evacuating to -0.08 to -0.1 MPa and maintaining for 30 minutes, injecting the second resin liquid and immersing under vacuum for 3 to 5 hours, and then pressurizing to 0.6 to 0.9 MPa and maintaining for 8 to 12 hours.

[0015] Preferably, in step S2, the first resin solution further includes methyltrimethoxysilane and anhydrous ethanol; The first resin liquid comprises, by weight, 40-60 parts of epoxy resin with an epoxy equivalent of 180-220, 20-30 parts of hydroxyl-terminated polyurethane prepolymer, 5-10 parts of methyltrimethoxysilane, and 10-20 parts of anhydrous ethanol.

[0016] Preferably, in step S3, the second resin liquid further includes methyltrimethoxysilane, anhydrous ethanol, distilled water, bamboo vinegar, polyethylene glycol, and latent amine curing agent; The second resin liquid comprises, by weight: 40-50 parts epoxy resin, 20-30 parts polyurethane prepolymer, 1-3 parts nanocellulose whiskers, 2-4 parts hydroxyl-terminated polydimethylsiloxane, 5-8 parts methyltrimethoxysilane, 10-15 parts anhydrous ethanol, 5-8 parts distilled water, 3-5 parts bamboo vinegar, 4-6 parts polyethylene glycol, and 3-8 parts latent amine curing agent.

[0017] The beneficial effects of this invention are: This invention precisely exposes the reaction sites of wood hemicellulose through selective enzymatic hydrolysis with hemicellulase, combined with directional grafting modification of C6-C18 alkenyl succinic anhydride. This fundamentally reduces the hygroscopicity of wood while completely preserving the natural acoustic framework composed of crystalline cellulose. Furthermore, a gradient-type dual-resin solution stepwise impregnation and gradient-temperature curing process allows the flexible interface resin layer to tightly bond with the hydrophobic grafted chains of the wood, while the high-modulus multifunctional body layer resin fully fills the cell cavity, constructing a gradient modulus composite structure from the cell wall to the cell cavity. This eliminates the problem of resin and... The rigid stress concentration between wood particles avoids micro-cracking and vibration transmission loss. Furthermore, the in-situ reinforcement of nanocellulose whiskers and the hydrophobic and oleophobic modification of hydroxyl-terminated polydimethylsiloxane achieve multiple improvements in wood dimensional stability, wear resistance, and antibacterial properties. Ultimately, while significantly inhibiting the shrinkage and swelling deformation of woodwind instrument tubes, the acoustic vibration characteristics of wood are preserved and optimized to the maximum extent. This allows the treated tubes to have excellent environmental adaptability, durability, and acoustic performance, solving the industry problem that traditional wood stabilization treatments cannot simultaneously achieve dimensional stability and acoustic performance. Detailed Implementation

[0018] The present application will now be described in further detail with reference to embodiments. In the following description, certain specific details are included to provide a comprehensive understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments can be implemented without employing one or more of these specific details, but using other methods, components, materials, etc. Unless otherwise required by the present invention, the terms "comprising" and "including" should be interpreted in an open-ended, inclusive sense, meaning "including but not limited to". Throughout this specification, "an embodiment," "an embodiment," "a preferred embodiment," or "some embodiments" means that at least one embodiment includes a specific reference element, structure, or feature related to that embodiment. Therefore, the phrases "in an embodiment," "in an embodiment," "in a preferred embodiment," or "in some embodiments" appearing in different places throughout the specification do not necessarily all refer to the same embodiment. Furthermore, specific elements, structures, or features may be combined in one or more embodiments in any suitable manner.

[0019] According to a first aspect of the present invention, a stabilization treatment process for the wooden body of a woodwind musical instrument is provided, comprising the following steps: S1. The wooden tube blank is subjected to hemicellulase treatment and C6~C18 alkenyl succinic anhydride treatment in sequence to obtain the first blank; S2. The first blank is first impregnated with the first resin liquid and then pre-cured to obtain the second blank; S3. Impregnate the second blank with the second resin solution to obtain the third blank; S4. The third blank is cured to obtain a stabilized wooden tube for a woodwind instrument. The first resin liquid comprises an epoxy resin with an epoxy equivalent of 180-220 and a hydroxyl-terminated polyurethane prepolymer; The second resin liquid includes epoxy resin, polyurethane prepolymer, nanocellulose whiskers, and hydroxyl-terminated polydimethylsiloxane.

[0020] In this invention, the acoustic conduction core of hardwoods such as ebony, mahogany, and maple used in woodwind instruments is crystalline cellulose, while hemicellulose is the main carrier of hygroscopic hydroxyl groups in wood and a major component of amorphous regions. Directional treatment with hemicellulase degrades and exposes only the reaction sites of hemicellulose without damaging the structure of crystalline cellulose, fundamentally avoiding the damage to the acoustic vibration characteristics of wood caused by indiscriminate modification and laying the foundation for preserving subsequent acoustic properties.

[0021] By utilizing the esterification reaction between acid anhydride and hemicellulose hydroxyl groups, C6-C18 alkenyl segments are grafted onto the wood, directly shielding the hygroscopic hydroxyl groups of the wood. This reduces the wood's tendency to shrink and swell with changes in temperature and humidity, thereby improving dimensional stability. At the same time, the grafted C6-C18 alkenyl groups provide a compatibility target for subsequent resin impregnation, solving the problems of poor interfacial compatibility between traditional resins and wood cell walls, which can easily lead to stress concentration.

[0022] This invention selects low molecular weight epoxy resin with an epoxy equivalent of 180~220 and hydroxyl-terminated polyurethane prepolymer as important raw materials for the first resin liquid. The low molecular weight epoxy resin can penetrate deep into the surface of the wood cell wall, while the polyurethane prepolymer gives the resin flexible chain segments. The resin liquid composed of the two has both permeability and flexibility, and is adapted to the microstructure of the wood cell wall.

[0023] The hydroxyl-terminated polyurethane prepolymer selected in this invention is preferably a polyether-type hydroxyl-terminated polyurethane prepolymer, which has better hydrolysis resistance and flexibility suitable for the use of woodwind instruments, and has excellent compatibility with epoxy resin and methyltrimethoxysilane, ensuring uniform penetration and pre-curing effect of the first resin solution. Desmophen 1100 or Wanhua Chemical WANNATE® DP-100 are preferred.

[0024] Pre-curing involves short-term, low-temperature treatment (60-80°C, 1-2 hours) to induce partial cross-linking of the resin, forming a stable physical morphology. At this stage, the degree of cross-linking is controlled at 30%-50%, not yet fully cross-linked. Full cross-linking requires subsequent high-temperature curing. The degree of cross-linking can be determined by differential scanning calorimetry (DSC). Using the area of ​​the exothermic peak when the resin is fully cross-linked as a benchmark, the remaining percentage of the exothermic peak area after pre-curing is the uncross-linked proportion, corresponding to a cross-linking degree of 30%-50%.

[0025] This process ensures that the resin and the hydrophobic alkenyl groups grafted with S1 form physical entanglement or chemical cross-linking, constructing a flexible transition layer between the wood cell wall and the subsequent bulk resin, thus avoiding rigid abrupt changes caused by the direct contact of the high-modulus resin with the wood. It also prevents resin loss during subsequent transfer and secondary impregnation of the blank, ensuring process stability.

[0026] Epoxy resin and polyurethane prepolymer retain the high modulus characteristics of epoxy resin and combine with the toughness of polyurethane prepolymer. When used to fill the cell cavity of wood, they can improve the overall structural strength and dimensional stability of wood and prevent the tube from deforming or cracking due to external forces or environmental changes.

[0027] The polyurethane prepolymer in the second resin solution of this invention refers to a polymer intermediate obtained through a stepwise polymerization reaction of polyol and diisocyanate. Its molecular chain contains incompletely reacted active groups and does not form a three-dimensional cross-linked network, allowing for further reaction with epoxy resin, latent amine curing agents, and other components. This prepolymer is not a single, fixed structure; its molecular weight and active group content can be flexibly controlled by adjusting the type of polyol, the type of diisocyanate, and the molar ratio of raw materials. The polyurethane prepolymer in the second resin solution focuses on synergistically forming a high-modulus bulk structure with epoxy resin. Therefore, a slightly branched type is preferred, balancing rigidity and toughness. This type complements the linear hydroxyl-terminated polyurethane prepolymer in the first resin solution, which emphasizes flexible chain segment buffering. Its compatibility and cross-linking reactivity with epoxy resin have been industrially verified, ensuring that after the second resin solution fills the wood cell cavities, it forms a dense, uniformly stressed bulk layer, improving the dimensional stability and wear resistance of the tube without disrupting the acoustic vibration transmission path of the wood.

[0028] The polyurethane prepolymer in the second resin liquid of the present invention is, for example, Desmodur N3300, Wanhua Chemical WANNATE® PM-200 or BASF Lupranate M20S.

[0029] Nanocellulose whiskers have excellent compatibility with wood matrix and form an in-situ reinforcing network after filling, which improves wear resistance without affecting the vibration transmission of wood. After participating in cross-linking, hydroxyl-terminated polydimethylsiloxane gives the wood permanent hydrophobic and oleophobic properties, which can resist the wetting of the player's saliva and prevent pitch fluctuations. At the same time, it further improves the weather resistance of the wood. The combination of the two gives the tube a combination of wear resistance, hydrophobicity and anti-wetting properties on the basis of stability, making it suitable for the actual use of woodwind instruments.

[0030] In a preferred embodiment of the present invention, the hemicellulase in step S1 includes xylanase and / or mannanase.

[0031] In this invention, the core hemicellulose components of hardwoods such as ebony, mahogany, and maple used in woodwind instruments are xylan and mannan. Xylanase can specifically catalyze the hydrolysis of xylan glycosidic bonds, and mannanase can directionally degrade mannan. The two, used alone or in combination, can achieve precise enzymatic hydrolysis of hardwood hemicellulose without degrading the crystalline cellulose that serves as the core of acoustic conduction in wood. This fundamentally ensures the integrity of the natural acoustic framework of the wood and avoids the damage to the acoustic performance of the instrument caused by indiscriminate enzymatic hydrolysis.

[0032] Xylanase and mannanase have a mild enzymatic hydrolysis effect, which can only degrade hemicellulose in the amorphous region of wood cell wall, moderately decompose it and expose hydroxyl reaction sites, and will not cause the wood cell wall structure to become loose or the mechanical strength to decrease due to excessive enzymatic hydrolysis. This balances the dual requirements of exposing reaction sites and maintaining the stability of the matrix structure.

[0033] In addition, the enzymatic hydrolysis products of both are monosaccharides or oligosaccharides, without the generation of acidic or alkaline byproducts. They will not change the acid-base environment of the wood matrix, nor will they cause unexpected side reactions with the subsequent C6~C18 alkenyl succinic anhydride and resin solution, ensuring the consistency of the modification effect.

[0034] Meanwhile, the optimal operating conditions for xylanase and mannanase are a temperature of 40-50℃ and a pH of 5.0-6.0, which highly match the process parameters of S1 in this invention. No additional adjustments to the temperature, pH, or other conditions of the reaction system are required. The enzymatic hydrolysis time of 1-3 hours is easily controlled, and the degree of hydrolysis can be precisely controlled by adjusting the enzyme concentration, resulting in strong process controllability. Furthermore, both are commonly used industrial enzymes, with readily available and moderately priced raw materials. No dedicated enzymatic hydrolysis equipment is required; the process can be completed directly in existing reaction vessels, perfectly meeting the industrial-scale mass production requirements for the stabilization treatment of woodwind instrument bodies.

[0035] In this invention, the hemicellulase mentioned in step S1 is, for example, xylanase, mannanase, or a combination of xylanase and mannanase.

[0036] In a preferred embodiment of the present invention, the curing process in step S4 includes a gradient temperature curing process: first drying at 60~70℃ for 4~6 hours, then drying at 80~90℃ for 2~4 hours, and finally drying at 100~110℃ for 2~3 hours, with a heating rate ≤5℃ / h.

[0037] In this invention, a gradient temperature rise of 60~70℃→80~90℃→100~110℃ is used for curing, and the temperature rise rate is ≤5℃ / h. This allows the resin system to gradually crosslink from the flexible interface layer to the rigid body layer, forming a composite structure with a modulus gradient from the cell wall to the cell cavity. This completely eliminates the internal stress generated during the resin curing process and avoids micro-cracking. Slow, gradient heating prevents sudden temperature increases that could damage wood fibers due to thermal expansion, while allowing the latent curing agent to be activated evenly, ensuring uniform resin cross-linking, and guaranteeing the overall structural stability of the treated wood. Furthermore, it preserves the acoustic vibration transmission path, ultimately achieving compatibility between dimensional stability and acoustic performance.

[0038] This invention abandons the traditional approach of simple impregnation and indiscriminate modification in wood modification. Instead, it uses a step-by-step process that combines targeted modification to reduce moisture absorption, flexible interfaces to eliminate stress, functional resins to strengthen the structure, and gradient curing to ensure uniformity. This collaboratively addresses the two conflicting needs of improving the stability of wood modification and preserving its acoustic properties.

[0039] In this invention, in addition to the preferred gradient temperature curing process, the curing process in step S4 can also employ a conventional step temperature curing process or a traditional random curing process.

[0040] The conventional stepped isothermal curing process refers to the process of first drying the material at a lower temperature (70-80℃) for about 5-10 hours to remove residual solvent and some moisture, and then raising the temperature to a higher temperature (100-110℃) for 3-8 hours to allow the resin to complete cross-linking and shaping. Unlike the gradient temperature curing process, the conventional stepped isothermal curing process only sets 2-3 discrete isothermal sections, and the heating rate is not strictly limited, usually 5-10℃ / h. It also does not require a slow heating transition between each temperature section, making the process simpler but with a weaker stress balance effect.

[0041] This process achieves basic cross-linking and curing of the resin, giving the tube a certain degree of dimensional stability and functionality, which is superior to traditional random curing processes. However, due to the lack of a low-speed gradient heating stress balancing process, the uniformity of resin cross-linking and the control of internal stress in the wood-resin composite system are weaker than those of gradient heating curing. Therefore, the dimensional stability and acoustic vibration transmission performance of the tube are slightly inferior to those of tubes cured by gradient heating. The ordinary stepped isothermal curing process allows for adjustment of temperature and holding time according to actual production needs, as long as the resin completes cross-linking and curing and a sudden temperature rise is avoided to prevent thermal deformation of the wood.

[0042] The traditional irregular curing process refers to a process mode in which the blank is directly placed in a fixed high-temperature environment for one-time curing without clear temperature segmentation and heating rate control, or the curing temperature is arbitrarily adjusted (such as directly raising it from 20~30℃ to 100~110℃ and holding it at that temperature). This process does not consider the resin cross-linking law and the thermal expansion characteristics of wood, which easily leads to rapid boiling of the solvent, resulting in micropores, uneven resin cross-linking, stress concentration between wood and resin, and even micro-cracks in the wood cell walls. It is a common extensive curing method in existing technologies.

[0043] In a preferred embodiment of the present invention, before the gradient temperature curing process in step S4, the third blank is naturally air-dried for 24 to 48 hours.

[0044] In this invention, the third blank is air-dried naturally for 24-48 hours before gradient temperature curing. This allows the solvent and moisture to evaporate slowly and evenly, avoiding the violent boiling of the solvent that produces bubbles and micropores during direct high-temperature curing, thus preventing micro-cracking of the wood cell walls. At the same time, it allows the resin to be further evenly distributed in the pores, ensuring dense filling. It also balances the moisture content inside and outside the blank and the initial internal stress. Blanks that have been impregnated twice are prone to uneven moisture content and internal stress caused by resin adsorption. Air drying at room temperature can gently regulate the moisture balance, slowly release stress, and prevent the tube from warping and deforming due to subsequent temperature increases. Natural air drying for 24-48 hours allows the resin and functional components to complete pre-adsorption and shaping. At room temperature, the latent curing agent is inactive, and the resin molecules can tightly bind with the hydrophobic groups of wood and the interfacial resin. Functional components such as nanocellulose whiskers can also be evenly dispersed, avoiding component aggregation during high-temperature curing and reducing the modification effect. At the same time, it achieves a smooth transition from room temperature to gradient temperature rise, reduces interfacial stress caused by differences in thermal expansion coefficients, and ensures the formation of gradient modulus composite structures.

[0045] In a preferred embodiment of the present invention, step S1, which involves sequentially treating the wooden tube blank with hemicellulase and C6-C18 alkenyl succinic anhydride, comprises: The wooden tube blank is placed in a reaction vessel and soaked in a hemicellulase solution for 1 to 3 hours. The concentration of the hemicellulase solution is 0.5% to 2%, the pH value is 5.0 to 6.0, and the temperature is 40 to 50°C. After draining the hemicellulase solution and washing with deionized water, an organic solution containing C6-C18 alkenyl succinic anhydride is injected and reacted for 2-5 hours. The mass fraction of the C6-C18 alkenyl succinic anhydride is 5%-15%, and the reaction temperature is 50-70℃. After the reaction is complete, the residual liquid is discharged, washed with ethanol, and dried at 55-65℃ until the water content is 10%-15%.

[0046] In this invention, the concentration of the hemicellulase solution is 0.5%~2%, the pH value is 5.0~6.0, the temperature is 40~50℃, and the soaking treatment is 1~3 hours because these conditions are the optimal range of action for xylanase / mannanase, which can gently and accurately degrade hemicellulose in the amorphous region of hardwood and expose hydroxyl reaction sites. This avoids insufficient enzymatic hydrolysis leading to low subsequent grafting efficiency, and also prevents excessive enzymatic hydrolysis from damaging the wood cell wall structure and affecting the mechanical and acoustic properties of the tube. Washing with deionized water can thoroughly remove residual enzyme solution, avoid unexpected reactions with subsequent acid anhydrides and organic solutions, and ensure the purity of the grafting reaction.

[0047] The parameters and operating procedures for treating C6-C18 alkenyl succinic anhydride are limited to a mass fraction of 5%-15%, a reaction temperature of 50-70℃, and a reaction time of 2-5 hours. This enables highly efficient and selective esterification of the anhydride and hemicellulose hydroxyl groups. The grafted C6-C18 long-chain alkenyl groups effectively shield hygroscopic hydroxyl groups, reducing the wood's shrinkage and swelling characteristics at the source. The alkenyl groups of this carbon chain length possess both hydrophobicity and flexibility, preserving the wood's vibrational conduction properties while providing a compatible anchor point for subsequent resin impregnation. Using an organic solvent ensures uniform dispersion of the anhydride, improving the uniformity of the grafting.

[0048] Ethanol washing can quickly remove unreacted acid anhydrides and byproducts, preventing residues from clogging the micropores of the wood or affecting subsequent resin penetration; drying at 55~65℃ to a moisture content of 10%~15% ensures that the residual solvent evaporates completely and that the moisture content of the wood is within the suitable range for subsequent resin impregnation. Too high a moisture content can easily lead to uneven resin cross-linking, while too low a moisture content will cause the wood cell walls to shrink, affecting the resin penetration effect. This moisture content range can take into account both the stability of the wood structure and the continuity of subsequent processes.

[0049] In a preferred embodiment of the present invention, the organic solution containing C6-C18 alkenyl succinic anhydride further includes a catalyst; The catalyst comprises at least one of 4-dimethylaminopyridine, triethylamine, anhydrous sodium carbonate, or dicyclohexylcarbodiimide (DCC).

[0050] In this invention, a catalyst is used to efficiently catalyze the esterification reaction of C6-C18 alkenyl succinic anhydride with hemicellulose hydroxyl groups, while also adapting to the process and the hardwood modification requirements of woodwind instruments. 4-Dimethylaminopyridine, triethylamine, anhydrous sodium carbonate, or dicyclohexylcarbodiimide (DCC) can accelerate esterification through different mechanisms, improve the grafting efficiency of hydrophobic segments, and ensure effective modification is completed within the process time. The catalytic conditions are mild, with no strong acid or base byproducts, and will not degrade crystalline cellulose or damage the acoustic framework of the wood. It is compatible with ethanol / acetone organic systems, with no unexpected side reactions, and is easily removed by ethanol washing, leaving no residue that affects subsequent resin impregnation. A variety of catalysts can be flexibly selected to adapt to different alkenyl carbon chains, solvents, and preform types, meeting the needs of industrial production.

[0051] In a preferred embodiment of the present invention, the impregnation of the first resin liquid in step S2 includes: evacuating to -0.08 to -0.1 MPa and maintaining for 30 to 40 minutes, injecting the first resin liquid and immersing under vacuum for 2 to 4 hours, and then pressurizing to 0.3 to 0.5 MPa and maintaining for 2 to 3 hours; The pre-curing conditions are 60~80℃ for 1~2 hours.

[0052] In this invention, evacuating to -0.08~-0.1MPa and holding the pressure for 30~40min can fully remove the air from the cell cavities and cell wall gaps of the wood, eliminate the resistance to resin penetration, create a vacuum environment for the full immersion of the resin liquid, avoid residual air causing the resin to not fill densely, and ensure the contact area between the interface layer resin and the wood.

[0053] Vacuum soaking for 2-4 hours allows the resin liquid to slowly and evenly penetrate to the cell wall surface, fully contacting the hydrophobic alkenyl groups grafted with S1; applying pressure of 0.3-0.5 MPa and holding for 2-3 hours further promotes the resin to adhere to the cell wall surface, promoting physical entanglement or slight cross-linking between the two, and the low pressure of 0.3-0.5 MPa will not damage the wood cell wall structure, thus avoiding affecting the integrity of the acoustic skeleton.

[0054] Pre-curing at 60~80℃ for 1~2 hours only allows the resin to initially cross-link and solidify, preventing resin loss during subsequent transportation and secondary impregnation, while retaining the resin's reactivity so that it can co-crosslink with the subsequent body layer resin; at the same time, low-temperature pre-curing will not cause wood thermal deformation, and will also avoid excessive resin curing leading to excessive rigidity of the interface layer, ensuring the formation of a flexible transition layer.

[0055] In a preferred embodiment of the present invention, the first resin solution in step S2 further includes methyltrimethoxysilane and anhydrous ethanol; The first resin liquid comprises, by weight, 40-60 parts of epoxy resin with an epoxy equivalent of 180-220, 20-30 parts of hydroxyl-terminated polyurethane prepolymer, 5-10 parts of methyltrimethoxysilane, and 10-20 parts of anhydrous ethanol.

[0056] In this invention, ethanol has good compatibility with epoxy resin and polyurethane prepolymer, which can reduce the viscosity of the resin liquid, allowing it to penetrate smoothly into the surface of the wood cell wall. It is also easy to volatilize and leaves no residue, so it will not affect the subsequent pre-curing and cross-linking reaction. The ratio of 10 to 20 parts can precisely control the viscosity of the resin liquid, ensuring penetration efficiency while avoiding excessive solvent leading to too low resin concentration and failure to form a uniform interface layer.

[0057] The combination of 40-60 parts low molecular weight epoxy resin and 20-30 parts hydroxyl-terminated polyurethane prepolymer gives the resin liquid both rigidity and flexibility. The short molecular chains of the low molecular weight epoxy resin with an epoxy equivalent of 180-220 make it easy to penetrate into the cell wall surface. The flexible segments of the polyurethane prepolymer can eliminate the rigid stress between the resin and the wood. The ratio range of the two can accurately construct a suitable flexible transition layer, which ensures the structural strength of the interface layer without damaging the acoustic vibration characteristics of the wood.

[0058] 5-10 parts of methyltrimethoxysilane can react with the hydroxyl groups of wood and the resin groups simultaneously, forming a chemical bridge between the wood and the resin, greatly improving the interfacial bonding force and preventing the resin layer from falling off. At the same time, the siloxane groups formed after hydrolysis can further improve the hydrophobicity and weather resistance of the interfacial layer. It works synergistically with the hydrophobic alkenyl groups grafted with S1 to enhance the moisture resistance of the wood. Moreover, this amount of addition will not block the micropores of the wood due to the self-polymerization of silane, ensuring the penetration effect of subsequent resin impregnation.

[0059] In this invention, after the first resin liquid is impregnated and penetrates to the surface of the wood cell wall under vacuum pressure, the thin transitional structure formed by pre-curing is the interface layer. This interface layer is a key intermediate layer connecting the wood cell wall and the bulk layer formed by the second resin liquid, thus forming a gradient composite structure of cell wall-interface layer-bulk layer. The interface layer focuses on solving the compatibility problem between wood and resin, while the bulk layer focuses on strengthening the structure and function. The two work together to achieve stress relief and performance optimization.

[0060] In this invention, the epoxy resin with an epoxy equivalent of 180 to 220 is, for example, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, or 60 parts by weight.

[0061] The hydroxyl-terminated polyurethane prepolymer is, for example, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, or 30 parts.

[0062] The methyltrimethoxysilane is present in parts by weight, for example, 5, 6, 7, 8, 9, or 10 parts.

[0063] The weight parts of anhydrous ethanol are, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 parts.

[0064] In a preferred embodiment of the present invention, the second resin liquid in step S3 further includes methyltrimethoxysilane, anhydrous ethanol, distilled water, bamboo vinegar, polyethylene glycol, and latent amine curing agent. The second resin liquid comprises, by weight: 40-50 parts epoxy resin, 20-30 parts polyurethane prepolymer, 1-3 parts nanocellulose whiskers, 2-4 parts hydroxyl-terminated polydimethylsiloxane, 5-8 parts methyltrimethoxysilane, 10-15 parts anhydrous ethanol, 5-8 parts distilled water, 3-5 parts bamboo vinegar, 4-6 parts polyethylene glycol, and 3-8 parts latent amine curing agent.

[0065] In this invention, 40-50 parts of epoxy resin and 20-30 parts of polyurethane prepolymer are used as the core resin of the body layer. The epoxy resin ensures high modulus and structural strength, while the polyurethane prepolymer adds toughness. This ratio allows the resin to fill the cell cavity, which not only improves the overall dimensional stability and wear resistance of the wood, but also avoids excessive rigidity from affecting the vibration transmission of the wood. At the same time, it can co-crosslink with the interface layer resin to form a continuous gradient modulus structure.

[0066] The nanocellulose whiskers described in this invention refer to rod-shaped or needle-shaped nanocrystalline materials obtained from natural cellulose by removing amorphous regions through methods such as mechanical exfoliation, acid hydrolysis, and enzymatic hydrolysis. These whiskers typically have a diameter of 5-50 nm, a length of 100-1000 nm, and a crystallinity ≥85%. Their molecular chain surfaces are rich in hydroxyl groups (-OH), allowing them to undergo physical interactions or chemical cross-linking with resin systems. Examples include CelluForce CNF, Daicel NCW, or CNW-100 from the Institute of Physics and Chemistry, Chinese Academy of Sciences.

[0067] Nanocellulose whiskers exhibit excellent compatibility with the wood matrix, forming an in-situ reinforcing network that enhances hardness without compromising acoustic transmission. A formulation of 1-3 parts achieves a balance between reinforcement and dispersibility, improving the mechanical properties of the tube without disrupting the acoustic vibration transmission path of the wood. Hydroxyl-terminated polydimethylsiloxane participates in cross-linking, imparting permanent hydrophobic and oleophobic properties to the wood, resisting saliva penetration during performance and preventing pitch fluctuations. A formulation of 2-4 parts ensures the formation of a dense, permanent hydrophobic and oleophobic layer within the wood, achieving long-lasting anti-wetting and anti-hygroscopic properties, while also complementing the high modulus characteristics of epoxy resin and polyurethane prepolymer without affecting the structural stability of the bulk layer. These two components synergistically combine mechanical reinforcement with functional modification.

[0068] Methyltrimethoxysilane acts as a coupling agent, binding one end to the wood / interface layer resin and the other end to the body layer resin, strengthening the bonding force between layers and preventing interlayer delamination. At the same time, it improves the hydrophobicity and weather resistance of the body layer. It works synergistically with hydroxyl-terminated polydimethylsiloxane to enhance the moisture-proof effect. Moreover, an addition of 5-8 parts will not cause micropore blockage, ensuring acoustic performance.

[0069] The compound solvent precisely controls the resin viscosity, ethanol improves the compatibility between the resin and organic components, and distilled water promotes the hydrolysis of silane coupling agents. The ratio of 10-15 parts anhydrous ethanol to 5-8 parts distilled water allows the resin to fully penetrate and fill the wood cell cavities while ensuring that each component is evenly dispersed, avoiding the increase in acoustic damping caused by uneven filling.

[0070] Bamboo vinegar is a natural antibacterial component, giving the instrument tube excellent antibacterial and antifungal properties. It is suitable for use in musical instruments where the instrument is in prolonged contact with the human body. Furthermore, it is compatible with the resin system and will not affect resin cross-linking or the acoustic properties of the wood. A ratio of 3-5 parts ensures long-lasting antibacterial and antifungal effects while maintaining high compatibility with the resin system, without interfering with resin cross-linking and curing, and without negatively impacting the acoustic vibration characteristics of the wood. When used synergistically with nanocellulose whiskers, it can further enhance the durability of the instrument tube.

[0071] Polyethylene glycol, acting as a plasticizer and dispersant, further regulates resin viscosity, promotes resin penetration into the deep micropores of wood, and enhances the dispersibility of powder components such as nanocellulose whiskers. This ensures uniform performance of the bulk layer and prevents localized aggregation that could affect acoustic vibration and structural stability. A mixing ratio of 4-6 parts achieves both resin viscosity control and efficient powder dispersion, ensuring uniform bulk layer performance without negatively impacting resin cross-linking and curing, bulk layer structural strength, or the acoustic properties of wood. Furthermore, it is highly compatible with the proportions of other components, ensuring no impact on the overall resin system's impregnation, filling, and gradient cross-linking effects.

[0072] The latent amine curing agent is inactive at room temperature, ensuring low resin viscosity during the impregnation stage. It gradually activates during high-temperature gradient curing, initiating uniform cross-linking of the resin. The curing rate is adapted to the gradient temperature process, preventing excessively rapid curing from causing internal stress and resulting in micro-cracking of the wood, thus ensuring the stability of the tube structure and acoustic performance. A formulation ratio of 3-8 parts allows the curing agent's activation rate to perfectly match the gradient temperature process, achieving slow and uniform cross-linking of the resin. This ensures both cross-linking density and structural stability while avoiding internal stress. Furthermore, it is highly compatible with the proportions of other components in the second resin solution, without affecting the low viscosity characteristics and penetration filling effect of the resin during the impregnation stage, balancing process feasibility and overall tube performance.

[0073] In this invention, the latent amine curing agent includes dicyandiamide (DICY, CAS 461-58-5). The dicyandiamide curing agent has an activity temperature of 90~100℃, which is optimally compatible with the gradient temperature curing process of this invention. It can ensure that the resin has low viscosity during the impregnation stage and uniform cross-linking during the curing stage, thus avoiding the generation of internal stress.

[0074] In this invention, the epoxy resin is, for example, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts or 50 parts by weight.

[0075] The polyurethane prepolymer may be present in parts by weight of, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 parts.

[0076] The weight parts of the nanocellulose whiskers are, for example, 1 part, 2 parts or 3 parts.

[0077] The hydroxyl-terminated polydimethylsiloxane is, for example, 2, 3, or 4 parts by weight.

[0078] The methyltrimethoxysilane is present in parts by weight, for example, 5, 6, 7 or 8 parts.

[0079] The weight parts of anhydrous ethanol are, for example, 10, 11, 12, 13, 14 or 15 parts.

[0080] The weight of distilled water is, for example, 5, 6, 7 or 8 parts.

[0081] The bamboo vinegar liquid is in parts by weight, for example, 3, 4 or 5 parts.

[0082] The weight parts of polyethylene glycol are, for example, 4, 5 or 6 parts.

[0083] The latent amine curing agent may be present in parts by weight of, for example, 3, 4, 5, 6, 7, or 8 parts.

[0084] In a preferred embodiment of the present invention, the stabilization treatment process for the wooden body of a woodwind instrument specifically includes: S1. The wooden tube blank is subjected to hemicellulase treatment and C6~C18 alkenyl succinic anhydride treatment in sequence to obtain the first blank: The wooden tube blanks are sanded and dried to control the moisture content to 8%~12%. Then, they are placed in a sealed reaction vessel and soaked in a hemicellulase solution with a concentration of 0.5%~2%, pH 5.0~6.0, and temperature of 40~50℃ for 1~3 hours to degrade the hemicellulose in the wood cell wall and expose the reaction sites. Then, the enzyme solution is drained, washed with deionized water, and an organic solution containing C6-C18 alkenyl succinic anhydride is injected. The reaction is carried out at 50-70°C for 2-5 hours, so that the C6-C18 alkenyl succinic anhydride selectively esterifies with the hydroxyl groups on the hemicellulose, and long-chain alkenyl hydrophobic segments are grafted on. After the reaction is completed, the residual liquid is drained, unreacted substances are washed with ethanol, and finally dried at 60°C to a moisture content of 10%-15% to obtain the first billet. The organic solution containing C6-C18 alkenyl succinic anhydride has a mass fraction of 5%-15% and the solvent is anhydrous ethanol or acetone. A catalyst of 0.5%-1.0% of the total mass of the organic solution is added. The catalyst includes at least one of 4-dimethylaminopyridine, triethylamine, anhydrous sodium carbonate, or dicyclohexylcarbodiimide (DCC).

[0085] S2. The first blank is first impregnated with the first resin liquid, and then pre-cured to obtain the second blank: The first preform is placed in a vacuum pressure impregnation tank and evacuated to -0.08 to -0.1 MPa for 30 to 40 minutes. Under negative pressure, the first resin liquid is injected and vacuum-immersed for 2 to 4 hours to ensure that the preform is completely submerged. Then, the vacuum is released, and the pressure is increased to 0.3 to 0.5 MPa for 2 to 3 hours to allow the interfacial resin to fully penetrate and adsorb onto the cell wall surface, and to undergo physical entanglement or chemical cross-linking with the long-chain alkenes. After depressurization, the preform is removed and pre-cured at 60 to 80°C for 1 to 2 hours to allow the interfacial resin to initially set but not completely cure, thus obtaining the second preform. The first resin liquid comprises, by weight, 40-60 parts of epoxy resin with an epoxy equivalent of 180-220, 20-30 parts of hydroxyl-terminated polyurethane prepolymer, 5-10 parts of methyltrimethoxysilane, and 10-20 parts of anhydrous ethanol.

[0086] S3. Impregnate the second blank with the second resin solution to obtain the third blank: The second blank is placed in a vacuum pressure impregnation tank, and a vacuum is drawn to -0.08 to -0.1 MPa and maintained for 30 minutes. The second resin liquid is injected and vacuum-immersed for 3 to 5 hours. Then, the pressure is increased to 0.6 to 0.9 MPa and maintained for 8 to 12 hours to allow the resin to fully fill the wood cell cavities. After depressurization, the blank is taken out to obtain the third blank. The second resin liquid comprises, by weight: 40-50 parts epoxy resin, 20-30 parts polyurethane prepolymer, 1-3 parts nanocellulose whiskers, 2-4 parts hydroxyl-terminated polydimethylsiloxane, 5-8 parts methyltrimethoxysilane, 10-15 parts anhydrous ethanol, 5-8 parts distilled water, 3-5 parts bamboo vinegar, 4-6 parts polyethylene glycol, and 3-8 parts latent amine curing agent (dicyandiamide).

[0087] S4. The third blank is cured to obtain a stabilized wooden tube for woodwind instruments: The third blank is air-dried naturally for 24-48 hours, and then placed in an oven for staged temperature curing. First, dry at 60~70℃ for 4~6 hours, then raise the temperature to 80~90℃ and hold for 2~4 hours, and finally raise the temperature to 100~110℃ and hold for 2~3 hours. Throughout the process, control the heating rate to ≤5℃ / h, and control the relative humidity of the drying environment to 30%~40%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0088] The following examples all use ebony, mahogany, and maple as the raw materials for woodwind instrument bodies, suitable for standard clarinets and flutes. The raw materials are all pre-treated by sanding and drying to a moisture content of 8%~12%. In the examples below, CelluForce CNF is used as the nanocellulose whisker. Example 1 S1, Processing: The ebony blanks were placed in a sealed reaction vessel and soaked in xylanase (1% concentration, pH 5.5, 45℃) for 2 hours. The enzyme solution was then drained, and the blanks were washed with deionized water. The blanks were then treated with anhydrous ethanol solution containing dodecenyl succinic anhydride (C12, 10% by mass) and 0.5% 4-dimethylaminopyridine (by mass of the total organic solution). The mixture was reacted at 60℃ for 3 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 60℃ until the moisture content was 12%, thus obtaining the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.09MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 3 hours. Then the vacuum was released, the pressure was increased to 0.4MPa and maintained for 2.5 hours. After depressurization, the blank was taken out and pre-cured at 70℃ for 1.5 hours to obtain the second blank. The first resin solution consists of the following components by weight: 50 parts epoxy resin with an epoxy equivalent of 200, 25 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 8 parts methyltrimethoxysilane, and 15 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.09 MPa and maintained for 30 minutes, then injected with the second resin solution and vacuum-impregnated for 4 hours. After that, the pressure was increased to 0.7 MPa and maintained for 10 hours. After depressurization, the billet was removed to obtain the third billet. The second resin solution contains the following components by weight: 45 parts epoxy resin, 25 parts polyurethane prepolymer (BASF Lupranate M20S), 2 parts nanocellulose whiskers (CelluForce CNF), 3 parts hydroxyl-terminated polydimethylsiloxane, 6 parts methyltrimethoxysilane, 12 parts anhydrous ethanol, 6 parts distilled water, 4 parts bamboo vinegar, 5 parts polyethylene glycol, and 5 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 36 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 65℃ for 5 hours, then the temperature is raised to 85℃ and held for 3 hours, and finally the temperature is raised to 105℃ and held for 2.5 hours. The heating rate is controlled at 3℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 35%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0089] Example 2 S1, Processing: The rosewood blank was placed in a sealed reaction vessel and soaked in mannanase (concentration 0.5%, pH 5.0, 40℃) for 3 hours. Then the enzyme solution was drained, and the blank was washed with deionized water. Then, the blank was reacted with acetone solution containing hexenyl succinic anhydride (C6, mass fraction 5%) and 0.5% triethylamine (total mass of organic solution) was added. The reaction was carried out at 50℃ for 5 hours. After the reaction was completed, the residual liquid was drained, and the blank was washed with ethanol and dried at 55℃ to a moisture content of 10% to obtain the first blank. S2, Impregnation with the first resin solution: The first blank is placed in a vacuum pressure impregnation tank, vacuumed to -0.08MPa and maintained for 30 minutes. The first resin liquid is injected under negative pressure and vacuum impregnated for 2 hours. Then the vacuum is released, the pressure is increased to 0.3MPa and maintained for 2 hours. After depressurization, the blank is taken out and pre-cured at 60℃ for 2 hours to obtain the second blank. The first resin solution consists of the following components by weight: 40 parts epoxy resin with an epoxy equivalent of 180, 20 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 5 parts methyltrimethoxysilane, and 10 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.08 MPa and maintained for 30 minutes, then injected with the second resin solution and vacuum-impregnated for 3 hours. After that, the pressure was increased to 0.6 MPa and maintained for 8 hours. After depressurization, the billet was removed to obtain the third billet. The second resin solution contains the following components by weight: 40 parts epoxy resin, 20 parts polyurethane prepolymer (BASF Lupranate M20S), 1 part nanocellulose whiskers, 2 parts hydroxyl-terminated polydimethylsiloxane, 5 parts methyltrimethoxysilane, 10 parts anhydrous ethanol, 5 parts distilled water, 3 parts bamboo vinegar, 4 parts polyethylene glycol, and 3 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 24 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 60℃ for 6 hours, then the temperature is raised to 80℃ and held for 4 hours, and finally the temperature is raised to 100℃ and held for 3 hours. The heating rate is controlled at 2℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 30%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0090] Example 3 S1, Processing: Maple blanks were placed in a sealed reaction vessel and soaked in a mixture of xylanase and mannanase (mass ratio 1:1, concentration 2%, pH 6.0, 50℃) for 1 hour. The enzyme solution was then drained, and the blanks were washed with deionized water. The blanks were then reacted with an anhydrous ethanol solution containing octadecenyl succinic anhydride (C18, mass fraction 15%), and anhydrous sodium carbonate was added at 1.0% of the total mass of the organic solution. The reaction was carried out at 70℃ for 2 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 65℃ until the moisture content was 15% to obtain the first blank. S2, Impregnation with the first resin solution: The first blank is placed in a vacuum pressure impregnation tank, vacuumed to -0.1MPa and maintained for 30 minutes. The first resin liquid is injected under negative pressure and vacuum impregnated for 4 hours. Then the vacuum is released, the pressure is increased to 0.5MPa and maintained for 3 hours. After depressurization, the blank is taken out and pre-cured at 80℃ for 1 hour to obtain the second blank. The first resin solution consists of the following components by weight: 60 parts epoxy resin with an epoxy equivalent of 220, 30 parts hydroxyl-terminated polyurethane prepolymer (Desmophen 1100), 10 parts methyltrimethoxysilane, and 20 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.1 MPa and maintained for 30 minutes, then injected with the second resin solution and vacuum-impregnated for 5 hours. After that, the pressure was increased to 0.9 MPa and maintained for 12 hours. After depressurization, the billet was removed to obtain the third billet. The second resin solution contains the following components by weight: 50 parts epoxy resin, 30 parts polyurethane prepolymer (BASF Lupranate M20S), 3 parts nanocellulose whiskers, 4 parts hydroxyl-terminated polydimethylsiloxane, 8 parts methyltrimethoxysilane, 15 parts anhydrous ethanol, 8 parts distilled water, 5 parts bamboo vinegar, 6 parts polyethylene glycol, and 8 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 48 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 70℃ for 4 hours, then the temperature is raised to 90℃ and held for 2 hours, and finally the temperature is raised to 110℃ and held for 2 hours. The heating rate is controlled at 5℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 40%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0091] Example 4 S1, Processing: The ebony blanks were placed in a sealed reaction vessel and soaked in xylanase (concentration 1.2%, pH 5.2, 42℃) for 2.5 hours. Then the enzyme solution was drained, and the blanks were washed with deionized water. The blanks were then reacted with acetone solution containing octenyl succinic anhydride (C8, mass fraction 8%), and 0.6% of dicyclohexylcarbodiimide (DCC) was added to the total organic solution. The reaction was carried out at 55℃ for 4 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 62℃ to a moisture content of 11% to obtain the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.085MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 2.5 hours. Then the vacuum was released, the pressure was increased to 0.35MPa and maintained for 2.2 hours. After depressurization, the blank was taken out and pre-cured at 65°C for 1.2 hours to obtain the second blank. The first resin solution consists of the following components by weight: 45 parts epoxy resin with an epoxy equivalent of 190, 22 parts hydroxyl-terminated polyurethane prepolymer (Desmophen 1100), 7 parts methyltrimethoxysilane, and 13 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.085 MPa and maintained for 30 min, then the second resin solution was injected and vacuum impregnated for 3.5 h, and then pressurized to 0.75 MPa and maintained for 9 h; after depressurization, the billet was taken out to obtain the third billet; The second resin solution comprises the following components by weight: 42 parts epoxy resin, 23 parts polyurethane prepolymer (BASF Lupranate M20S), 1.5 parts nanocellulose whiskers, 2.5 parts hydroxyl-terminated polydimethylsiloxane, 7 parts methyltrimethoxysilane, 11 parts anhydrous ethanol, 7 parts distilled water, 3.5 parts bamboo vinegar, 4.5 parts polyethylene glycol, and 4 parts latent amine curing agent. S4 Curing: The third blank is air-dried naturally for 30 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 62℃ for 5.5 hours, then heated to 82℃ and held for 3.5 hours, and finally heated to 102℃ and held for 2.2 hours. The heating rate is controlled at 4℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 32%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0092] Example 5 S1, Processing: The rosewood blanks were placed in a sealed reaction vessel and soaked in mannanase (concentration 1.8%, pH 5.8, 48℃) for 1.5 hours. Then the enzyme solution was drained, and the blanks were washed with deionized water. The blanks were then soaked in anhydrous ethanol solution containing decenyl succinic anhydride (C10, mass fraction 12%), and 0.8% of 4-dimethylaminopyridine (total mass of organic solution) was added. The mixture was reacted at 65℃ for 2.5 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 58℃ to a moisture content of 14% to obtain the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.095MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 3.5 hours. Then the vacuum was released, the pressure was increased to 0.45MPa and maintained for 2.8 hours. After depressurization, the blank was taken out and pre-cured at 75°C for 1.8 hours to obtain the second blank. The first resin solution consists of the following components by weight: 55 parts epoxy resin with an epoxy equivalent of 210, 28 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 9 parts methyltrimethoxysilane, and 18 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.095 MPa and maintained for 30 min. The second resin liquid was injected and vacuum impregnated for 4.5 h. Then the pressure was increased to 0.8 MPa and maintained for 11 h. After depressurization, the billet was taken out to obtain the third billet. The second resin solution comprises the following components by weight: 48 parts epoxy resin, 28 parts polyurethane prepolymer (BASF Lupranate M20S), 2.5 parts nanocellulose whiskers, 3.5 parts hydroxyl-terminated polydimethylsiloxane, 7 parts methyltrimethoxysilane, 14 parts anhydrous ethanol, 6 parts distilled water, 4.5 parts bamboo vinegar, 5.5 parts polyethylene glycol, and 7 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 40 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 68℃ for 4.5 hours, then heated to 88℃ and held for 2.5 hours, and finally heated to 108℃ and held for 2.8 hours. The heating rate is controlled at 3.5℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 38%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0093] Example 6 S1, Processing: Maple blanks were placed in a sealed reaction vessel and soaked in a mixture of xylanase and mannanase (mass ratio 2:1, concentration 1.5%, pH 5.4, 44℃) for 2 hours. The enzyme solution was then drained, and the blanks were washed with deionized water. The blanks were then reacted with an acetone solution containing tetradecenyl succinic anhydride (C14, mass fraction 9%), and 0.7% triethylamine (total mass of organic solution) was added. The reaction was carried out at 58℃ for 3.5 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 61℃ to a moisture content of 12% to obtain the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.09MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 3 hours. Then the vacuum was released, the pressure was increased to 0.4MPa and maintained for 2.5 hours. After depressurization, the blank was taken out and pre-cured at 70℃ for 1.5 hours to obtain the second blank. The first resin solution consists of the following components by weight: 50 parts epoxy resin with an epoxy equivalent of 200, 25 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 8 parts methyltrimethoxysilane, and 15 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.09 MPa and maintained for 30 minutes, then injected with the second resin solution and vacuum-impregnated for 4 hours. After that, the pressure was increased to 0.7 MPa and maintained for 10 hours. After depressurization, the billet was removed to obtain the third billet. The second resin solution contains the following components by weight: 45 parts epoxy resin, 25 parts polyurethane prepolymer (BASF Lupranate M20S), 2 parts nanocellulose whiskers, 3 parts hydroxyl-terminated polydimethylsiloxane, 6 parts methyltrimethoxysilane, 12 parts anhydrous ethanol, 6 parts distilled water, 4 parts bamboo vinegar, 5 parts polyethylene glycol, and 5 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 36 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 65℃ for 5 hours, then the temperature is raised to 85℃ and held for 3 hours, and finally the temperature is raised to 105℃ and held for 2.5 hours. The heating rate is controlled at 3℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 35%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0094] Example 7 S1, Processing: The ebony blanks were placed in a sealed reaction vessel and soaked in xylanase (concentration 0.8%, pH 5.1, 41℃) for 2.8 hours. Then, the enzyme solution was drained, and the blanks were washed with deionized water. The blanks were then treated with an anhydrous ethanol solution containing hexadecyl succinic anhydride (C16, mass fraction 7%), and 0.6% of 4-dimethylaminopyridine + anhydrous sodium carbonate (mass ratio 1:1) of the total organic solution were added. The mixture was reacted at 52℃ for 4.5 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 56℃ until the moisture content was 10%, thus obtaining the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.082MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 2.2 hours. Then the vacuum was released, the pressure was increased to 0.32MPa and maintained for 2.1 hours. After depressurization, the blank was taken out and pre-cured at 62℃ for 1.9 hours to obtain the second blank. The first resin solution consists of the following components by weight: 42 parts epoxy resin with an epoxy equivalent of 185, 21 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 6 parts methyltrimethoxysilane, and 12 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.082 MPa and maintained for 30 min. The second resin solution was then injected and vacuum impregnated for 3.2 h. Then the pressure was increased to 0.65 MPa and maintained for 8.5 h. After depressurization, the billet was removed to obtain the third billet. The second resin solution comprises the following components by weight: 41 parts epoxy resin, 22 parts polyurethane prepolymer (WANNATE® PM-200) from Wanhua Chemical, 1.2 parts nanocellulose whiskers, 2.2 parts hydroxyl-terminated polydimethylsiloxane, 5.5 parts methyltrimethoxysilane, 10.5 parts anhydrous ethanol, 5.5 parts distilled water, 3.2 parts bamboo vinegar, 4.2 parts polyethylene glycol, and 3.5 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 26 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 61℃ for 5.8 hours, then heated to 81℃ and held for 3.8 hours, and finally heated to 101℃ and held for 2.9 hours. The heating rate is controlled at 2.5℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 31%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0095] Example 8 S1, Processing: The rosewood blanks were placed in a sealed reaction vessel and soaked in mannanase (concentration 1.6%, pH 5.7, 47℃) for 1.2 hours. Then, the enzyme solution was drained, and the blanks were washed with deionized water. The blanks were then soaked in an acetone solution containing heptenyl succinic anhydride (C7, mass fraction 13%), and 0.9% of dicyclohexylcarbodiimide (DCC) + triethylamine (mass ratio 2:1) of the total organic solution were added. The mixture was reacted at 68℃ for 2.2 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 64℃ until the moisture content was 15%, thus obtaining the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.098MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 3.8 hours. Then the vacuum was released, the pressure was increased to 0.48MPa and maintained for 2.9 hours. After depressurization, the blank was taken out and pre-cured at 78℃ for 1.1 hours to obtain the second blank. The first resin solution consists of the following components by weight: 58 parts epoxy resin with an epoxy equivalent of 215, 29 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 9.5 parts methyltrimethoxysilane, and 19 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.098 MPa and maintained for 30 min, then the second resin solution was injected and vacuum impregnated for 4.8 h, and then pressurized to 0.85 MPa and maintained for 11.5 h; after depressurization, the billet was taken out to obtain the third billet; The second resin solution comprises the following components by weight: 49 parts epoxy resin, 29 parts polyurethane prepolymer (WANNATE® PM-200) from Wanhua Chemical, 2.8 parts nanocellulose whiskers, 3.8 parts hydroxyl-terminated polydimethylsiloxane, 7.5 parts methyltrimethoxysilane, 14.5 parts anhydrous ethanol, 7.5 parts distilled water, 4.8 parts bamboo vinegar, 5.8 parts polyethylene glycol, and 7.5 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 45 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 69℃ for 4.2 hours, then heated to 89℃ and held for 2.2 hours, and finally heated to 109℃ and held for 2.1 hours. The heating rate is controlled at 4.5℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 39%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0096] Example 9 S1, Processing: Maple blanks (flute size) were placed in a sealed reaction vessel and soaked in a mixture of xylanase and mannanase (mass ratio 1:2, concentration 1%, pH 5.5, 45℃) for 2 hours. The enzyme solution was then drained, and the blanks were washed with deionized water. The blanks were then reacted with anhydrous ethanol solution containing nonenyl succinic anhydride (C9, mass fraction 10%), and anhydrous sodium carbonate was added at 0.5% of the total mass of the organic solution. The reaction was carried out at 60℃ for 3 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 60℃ to a moisture content of 12% to obtain the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.09MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 3 hours. Then the vacuum was released, the pressure was increased to 0.4MPa and maintained for 2.5 hours. After depressurization, the blank was taken out and pre-cured at 70℃ for 1.5 hours to obtain the second blank. The first resin solution consists of the following components by weight: 50 parts epoxy resin with an epoxy equivalent of 200, 25 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 8 parts methyltrimethoxysilane, and 15 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.09 MPa and maintained for 30 minutes, then injected with the second resin solution and vacuum-impregnated for 4 hours. After that, the pressure was increased to 0.7 MPa and maintained for 10 hours. After depressurization, the billet was removed to obtain the third billet. The second resin solution contains the following components by weight: 45 parts epoxy resin, 25 parts polyurethane prepolymer (WANNATE® PM-200) from Wanhua Chemical, 2 parts nanocellulose whiskers, 3 parts hydroxyl-terminated polydimethylsiloxane, 6 parts methyltrimethoxysilane, 12 parts anhydrous ethanol, 6 parts distilled water, 4 parts bamboo vinegar, 5 parts polyethylene glycol, and 5 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 36 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 65℃ for 5 hours, then the temperature is raised to 85℃ and held for 3 hours, and finally the temperature is raised to 105℃ and held for 2.5 hours. The heating rate is controlled at 3℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 35%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0097] Example 10 S1, Processing: Ebony blanks (large-diameter clarinet specifications) were placed in a sealed reaction vessel and soaked in xylanase (concentration 1.9%, pH 5.9, 49℃) for 1.1 hours. The enzyme solution was then drained, and the blanks were washed with deionized water. Then, 1.0% of 4-dimethylaminopyridine (total mass of organic solution) was added to an acetone solution containing pentadecenyl succinic anhydride (C15, mass fraction 6%) and reacted at 51℃ for 4.9 hours. After the reaction, the residual liquid was drained, and the blanks were washed with ethanol and dried at 59℃ to a moisture content of 13% to obtain the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.088MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 2.8 hours. Then the vacuum was released, the pressure was increased to 0.38MPa and maintained for 2.4 hours. After depressurization, the blank was taken out and pre-cured at 68℃ for 1.6 hours to obtain the second blank. The first resin solution consists of the following components by weight: 48 parts epoxy resin with an epoxy equivalent of 195, 24 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 7.5 parts methyltrimethoxysilane, and 16 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.088 MPa and maintained for 30 minutes. The second resin solution was then injected and vacuum impregnated for 3.8 hours. Then the pressure was increased to 0.72 MPa and maintained for 9.5 hours. After depressurization, the billet was removed to obtain the third billet. The second resin solution comprises the following components by weight: 46 parts epoxy resin, 26 parts polyurethane prepolymer (Desmodur N3300), 2.2 parts nanocellulose whiskers, 3.2 parts hydroxyl-terminated polydimethylsiloxane, 6.5 parts methyltrimethoxysilane, 13 parts anhydrous ethanol, 6.5 parts distilled water, 3.8 parts bamboo vinegar, 4.8 parts polyethylene glycol, and 6 parts dicyandiamide. S4 Curing: The third blank is air-dried naturally for 32 hours; then it is placed in an oven for segmented temperature curing: first, it is dried at 64℃ for 5.2 hours, then heated to 84℃ and held for 3.2 hours, and finally heated to 104℃ and held for 2.4 hours. The heating rate is controlled at 3.2℃ / h throughout the process, and the relative humidity of the drying environment is controlled at 34%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0098] Example 11 S1, Processing: The ebony blanks were placed in a sealed reaction vessel and soaked in xylanase (1% concentration, pH 5.5, 45℃) for 2 hours. The enzyme solution was then drained, and the blanks were washed with deionized water. The blanks were then treated with anhydrous ethanol solution containing dodecenyl succinic anhydride (C12, 10% by mass) and 0.5% 4-dimethylaminopyridine (by mass of the total organic solution). The mixture was reacted at 60℃ for 3 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 60℃ until the moisture content was 12%, thus obtaining the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.09MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 3 hours. Then the vacuum was released, the pressure was increased to 0.4MPa and maintained for 2.5 hours. After depressurization, the blank was taken out and pre-cured at 70℃ for 1.5 hours to obtain the second blank. The first resin solution consists of the following components by weight: 50 parts epoxy resin with an epoxy equivalent of 200, 25 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 8 parts methyltrimethoxysilane, and 15 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.09 MPa and maintained for 30 minutes, then injected with the second resin solution and vacuum-impregnated for 4 hours. After that, the pressure was increased to 0.7 MPa and maintained for 10 hours. After depressurization, the billet was removed to obtain the third billet. The second resin solution contains the following components by weight: 45 parts epoxy resin, 25 parts polyurethane prepolymer (Desmodur N3300), 2 parts nanocellulose whiskers, 3 parts hydroxyl-terminated polydimethylsiloxane, 6 parts methyltrimethoxysilane, 12 parts anhydrous ethanol, 6 parts distilled water, 4 parts bamboo vinegar, 5 parts polyethylene glycol, and 5 parts dicyandiamide. S4 ordinary stepped constant temperature curing process: The third blank is naturally air-dried for 36 hours; then it is placed in an oven and a constant temperature stepped curing process is adopted: first, it is dried at 80℃ for 6 hours, and then the temperature is raised to 105℃ for 4 hours. The heating rate is 8℃ / h, without low-speed gradient heating. The relative humidity of the drying environment is controlled at 35%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain a stabilized wooden tube for woodwind instruments.

[0099] Example 12 S1, Processing: The ebony blanks were placed in a sealed reaction vessel and soaked in xylanase (1% concentration, pH 5.5, 45℃) for 2 hours. The enzyme solution was then drained, and the blanks were washed with deionized water. The blanks were then treated with anhydrous ethanol solution containing dodecenyl succinic anhydride (C12, 10% by mass) and 0.5% 4-dimethylaminopyridine (by mass of the total organic solution). The mixture was reacted at 60℃ for 3 hours. After the reaction was completed, the residual liquid was drained, and the blanks were washed with ethanol and dried at 60℃ until the moisture content was 12%, thus obtaining the first blank. S2, Impregnation with the first resin solution: The first blank was placed in a vacuum pressure impregnation tank, and the vacuum was drawn to -0.09MPa and maintained for 30 minutes. The first resin liquid was injected under negative pressure and vacuum impregnated for 3 hours. Then the vacuum was released, the pressure was increased to 0.4MPa and maintained for 2.5 hours. After depressurization, the blank was taken out and pre-cured at 70℃ for 1.5 hours to obtain the second blank. The first resin solution consists of the following components by weight: 50 parts epoxy resin with an epoxy equivalent of 200, 25 parts hydroxyl-terminated polyurethane prepolymer (WANNATE® DP-100) from Wanhua Chemical, 8 parts methyltrimethoxysilane, and 15 parts anhydrous ethanol. S3, Impregnation with the second resin solution: The second billet was placed in a vacuum pressure impregnation tank, vacuumed to -0.09 MPa and maintained for 30 minutes, then injected with the second resin solution and vacuum-impregnated for 4 hours. After that, the pressure was increased to 0.7 MPa and maintained for 10 hours. After depressurization, the billet was removed to obtain the third billet. The second resin solution contains the following components by weight: 45 parts epoxy resin, 25 parts polyurethane prepolymer (Desmodur N3300), 2 parts nanocellulose whiskers, 3 parts hydroxyl-terminated polydimethylsiloxane, 6 parts methyltrimethoxysilane, 12 parts anhydrous ethanol, 6 parts distilled water, 4 parts bamboo vinegar, 5 parts polyethylene glycol, and 5 parts dicyandiamide. S4 Traditional Irregular Curing: The third blank is air-dried naturally for 36 hours; it is then placed directly in a 100℃ oven for one-time constant temperature curing for 8 hours, with natural temperature rise at a rate of about 15℃ / h. The relative humidity of the drying environment is controlled at 35%. The surface of the tube is sanded and polished with 600-grit sandpaper to obtain the wooden tube of the woodwind instrument.

[0100] Comparative Example 1 S1, Processing: The ebony blank was directly injected into an anhydrous ethanol solution containing dodecenyl succinic anhydride (C12, 10% by mass), and 0.5% 4-dimethylaminopyridine was added. The mixture was reacted at 60°C for 3 hours. After washing with ethanol, the mixture was dried at 60°C until the moisture content was 12%.

[0101] The subsequent steps S2, S3, and S4 are completely consistent with those in Example 1.

[0102] Comparative Example 2 S1, Processing: The sample was soaked for 2 hours with broad-spectrum cellulase (Sigma-Aldrich C2730, derived from Trichoderma reesei, enzyme activity ≥700 units / g, concentration 1%, pH 5.5, 45℃), and the remaining alkenyl succinic anhydride treatment steps were the same as in Example 1.

[0103] The subsequent steps S2, S3, and S4 are completely consistent with those in Example 1.

[0104] Comparative Example 3 S1. The steps are completely consistent with those in Example 1, and the first blank is obtained; The S2 first resin liquid impregnation and pre-curing step is omitted, and the first blank is directly impregnated with the S3 second resin liquid with the same parameters as in Example 1. The subsequent S4 step is the same as in Example 1. Comparative Example 4 Steps S1 and S2 are completely consistent with those in Example 1; S3 second resin solution removes nano-cellulose whiskers and hydroxyl-terminated polydimethylsiloxane, and the remaining components, proportions and impregnation parameters are the same as in Example 1; The subsequent S4 steps are the same as in Example 1.

[0105] Comparative Example 5 Skip steps S1 and S2, directly vacuum the ebony blank to -0.09MPa for 35 minutes, inject epoxy resin with a pure epoxy equivalent of 200, vacuum soak for 3 hours, and pressurize to 0.4MPa for 2.5 hours.

[0106] The product is directly cured at 70℃ for 5 hours using a non-gradient heating process, followed by grinding and polishing.

[0107] Comparative Example 6 S1, Processing: The ebony blank was directly injected into an anhydrous ethanol solution containing dodecenyl succinic anhydride (C12, 10% by mass), and 0.5% 4-dimethylaminopyridine was added. The mixture was reacted at 60°C for 3 hours. After washing with ethanol, the blank was dried at 60°C to a moisture content of 12% (hemicellulase treatment was omitted). S2, Impregnation with the first resin solution: Completely identical to Example 12; S3, Impregnation with the second resin solution: Completely identical to Example 12; S4 Traditional Irregular Curing: Completely consistent with Example 12 (direct curing at 100°C for 8 hours, followed by natural temperature rise).

[0108] Performance testing Air-dry density: GB / T1933-2009 "Methods for Determination of Wood Density"; Volumetric shrinkage rate: GB / T 1934.2-2021 "Method for Determination of Shrinkage of Wood"; Moisture swelling rate: GB / T 1934.1-2021 "Method for Determination of Moisture Swelling of Wood"; Surface hardness: LY / T 1730-2008 "Method for Determination of Surface Hardness of Wood"; Water contact angle: GB / T 30693-2014 "Determination of contact angle of plastics"; Soybean oil contact angle: GB / T 30693-2014 "Determination of contact angle of plastics"; Acoustic performance: (1) Timbre and sound quality evaluation Test environment: Anechoic chamber (background noise ≤30dB(A)), temperature 20±2℃, relative humidity 50±5%; Test equipment: professional audio acquisition system (sampling rate ≥48kHz, resolution ≥24bit), microphone (frequency response range 20Hz~20kHz), microphone 30cm away from the mouthpiece of the tube, at a 45° angle to the axis of the tube; Performance test: A professional woodwind player will play the C major scale (3 notes each in the low, middle, and high registers) using standard playing technique, with each note lasting 3 seconds, and repeated 3 times; Subjective evaluation: An evaluation panel of 5 acoustic engineers and instrumentalists was invited to score the performance based on four dimensions (1-10 points): fullness of tone, clarity of high frequencies, richness of low frequencies, and degree of absence of noise. The final written conclusion was formed by combining auditory descriptions. (2) Pitch stability test The actual pitch of the played notes is collected using a pitch meter (accuracy ±1 cent), compared with the standard pitch, and the pitch deviation is calculated. Environmental simulation: After equilibration for 24 hours in environments of 15℃ (low humidity) and 30℃ (high humidity), the test was repeated to evaluate the effect of temperature and humidity changes on pitch accuracy.

[0109] Table 1 Performance Test Results

[0110] Acoustic performance of each embodiment compared to the examples: Example 1 The tone is full and clear, with bright high frequencies and rich low frequencies. It has a sensitive vibration response and excellent pitch stability. During performance, the transition between high and low frequencies is natural, with no obvious noise. The vibration of the tube is evenly transmitted, and even under varying temperature and humidity conditions, the pitch deviation is kept within a very small range, fully meeting the acoustic quality requirements for professional performance.

[0111] Example 2 With a warm and natural tone, it combines the unique softness of rosewood with clear acoustic performance. Vibration transmission is uniform, pitch deviation is small, playing sensitivity is good, mid-low frequency resonance is full, and high frequency penetration is moderate, making it suitable for daily performance and practice scenarios, with outstanding acoustic performance stability.

[0112] Example 3 With a rich and full tone, smooth transition between high and low frequencies, and gentle vibration decay, it boasts optimal acoustic performance. The natural acoustic properties of maple wood are fully preserved through modification treatment, resulting in clear, non-harsh high frequencies, deep, non-muddy low frequencies, fast vibration response, and excellent pitch stability, meeting the high demands of professional performances.

[0113] Example 4 The tone is pure and free of impurities, with rapid vibration response and stable and reliable pitch. There is no obvious obstruction in the transmission of the tube's vibration, with particularly outstanding performance in the mid and high frequencies. The tone is bright and transparent, and the breath feedback is sensitive during playing. Even after long periods of continuous playing, the acoustic performance does not fluctuate significantly, making it highly practical.

[0114] Example 5 With a full and mellow tone, smooth vibration transmission, and excellent pitch stability, the warm tone of the rosewood material is perfectly combined with the stability of the modification process. It has a deep low-frequency resonance, clear and transparent high frequencies, sufficient retention of vibration energy, and uniform decay, making it suitable for various playing styles.

[0115] Example 6 The tone is full and clear, with bright high frequencies and mellow low frequencies. It has a sensitive vibration response and excellent pitch stability. Similar to the acoustic performance of Example 1, the maple wood material gives it richer overtones, uniform vibration transmission, no obvious acoustic defects, and can accurately reproduce the performer's intention.

[0116] Example 7 The tone is natural and mellow, the vibration transmission is uniform, and the pitch deviation is small, meeting the usage requirements. Although the acoustic performance is slightly inferior to other gradient heating embodiments, the overall performance is balanced, the mid-low frequency tone is mellow, and the high frequency performance is stable without problems such as muffledness or harshness, making it suitable for the needs of entry-level professional musical instruments.

[0117] Example 8 With a full and rich tone, balanced high and low frequencies, sensitive vibration response, and excellent acoustic performance, the natural resonance characteristics of rosewood are fully utilized. It has a fast vibration transmission rate, high pitch stability, rich overtones, and can present a layered acoustic effect, making it suitable for professional performance scenarios.

[0118] Example 9 With a clear and bright tone, smooth vibration transmission, and suitable acoustic requirements for flute playing, the flute maintains stable pitch. It meets the high demands of the flute for acoustic transmission, exhibiting strong high-frequency penetration, natural transition between mid and low frequencies, sensitive vibration response, and minimal breath loss during performance. Its acoustic performance is comparable to that of traditional high-quality flutes.

[0119] Example 10 With a rich and full tone, sensitive vibration response, and acoustic characteristics well-suited for large-diameter clarinets, the instrument offers stable pitch. The large-diameter body provides outstanding low-frequency resonance, and after modification, it exhibits no muddiness. High frequencies are clear and transparent, with uniform vibration transmission, revealing the rich tonal layers unique to clarinets.

[0120] Example 11 The tone is generally pure, with vibration transmission slightly inferior to the gradient heating embodiment. Pitch stability is good, and there is no noticeable muffled sound. Due to the use of a standard stepped curing process, the vibration decay rate is slightly faster than the gradient heating embodiment, but the overall acoustic performance is balanced, with stable mid-high frequency performance and moderate low-frequency resonance, meeting the needs of daily practice and non-professional performances.

[0121] Example 12 The tone is free of noticeable noise, with slight attenuation in vibration transmission and average pitch stability, meeting basic usage requirements. Traditional irregular curing results in uneven resin cross-linking, slightly affecting vibration transmission; high-frequency performance is slightly inferior, and low-frequency resonance is insufficient. However, compared to instruments made using traditional methods, its acoustic performance still has certain advantages, making it suitable as an entry-level instrument.

[0122] Comparative Example 1 The tone is muffled, vibration transmission is obstructed, high-frequency response is insufficient, and pitch stability is average. Due to the lack of selective modification by hemicellulase, the integrity of the wood acoustic framework is affected, resulting in greater vibration energy loss, muddy low frequencies, and dull high frequencies. The acoustic performance is significantly inferior to all other embodiments.

[0123] Comparative Example 2 The tone is muffled, vibration attenuation is significant, the acoustic framework is damaged, high and low frequencies are unbalanced, and playing sensitivity is poor. Broad-spectrum cellulase destroys the crystalline cellulose structure of the wood, resulting in impaired acoustic transmission paths, a muddy and layered tone, large pitch fluctuations, and the worst acoustic performance among all tested samples.

[0124] Comparative Example 3 The tone is generally clear, but the vibration response is slightly sluggish, while the pitch stability is good. Due to the lack of a flexible interface layer, stress concentration occurs at the resin-wood interface, which slightly affects vibration transmission. The high-frequency performance is slightly inferior to the gradient heating example, and the low-frequency resonance is insufficient, but it is better than other comparative examples.

[0125] Comparative Example 4 The tone lacks purity, the low frequencies are slightly muddy, and the uniformity of vibration transmission is average. The lack of reinforcement with nano-cellulose whiskers and modification with hydroxyl-terminated polydimethylsiloxane increases tube vibration damping, causes excessively rapid low-frequency decay, and insufficient high-frequency penetration, resulting in acoustic performance inferior to all other embodiments.

[0126] Comparative Example 5 The tone is severely muffled, vibration is significantly impeded, pitch fluctuates greatly, and acoustic performance is poor. Traditional processes lack directional modification and gradient curing, resulting in uneven resin filling and poor compatibility with the wood interface. Vibration transmission is severely impeded, and high and low frequencies are severely unbalanced, failing to meet the needs of professional performance.

[0127] Comparative Example 6 The tone is muffled, vibration transmission is attenuated, pitch stability is average, and acoustic performance is inferior to Example 12. Lacking selective modification with hemicellulase and employing traditional random curing, the integrity of the wood acoustic framework and the uniformity of resin cross-linking are both affected, resulting in high vibration energy loss, a monotonous tone, and insufficient high-frequency response. Performance: The performance test results of the embodiments and comparative examples of this invention show that the process of selective modification with hemicellulase, gradient impregnation with dual resin solutions, and gradient temperature curing can achieve synergistic optimization of the dimensional stability, mechanical properties, and acoustic characteristics of woodwind instrument bodies. Examples 1-10 exhibit the best overall performance, with air-dry densities ranging from 1.02 to 1.12 g / cm³, volumetric shrinkage ≤0.80%, moisture expansion ≤0.88%, surface hardness 255-300 HB, water contact angle ≥110°, and soybean oil contact angle ≥98°. Acoustically, they all demonstrate a full and transparent tone, sensitive vibration response, and excellent pitch stability, fully verifying the protective effect of directional modification on the acoustic framework of the wood and the effect of gradient process on eliminating interfacial stress.

[0128] The performance of Examples 11 and 12 showed significant differences. Due to the lack of a stress balancing process with low-speed gradient heating in the curing process, the volume shrinkage rate and wet expansion rate of the two examples increased to more than 1.25% and 1.80%, respectively. Their acoustic performance was slightly inferior to that of the gradient heating examples, but still better than the comparative examples that lacked the core process. This proves the fundamental role of the pre-modification process of the present invention in improving performance.

[0129] Due to defects such as omitting hemicellulase treatment, replacing specific enzymes, and lacking double resin impregnation, the performance of each comparative example was significantly degraded: the volume shrinkage rate was ≥1.32%, the wet expansion rate was ≥1.58%, the surface hardness was generally lower than 250HB, the hydrophobic and oleophobic properties were greatly reduced, the water contact angle was ≤95°, and acoustically, many problems such as muffled tone, obstructed vibration, and pitch fluctuations were observed. Among them, comparative examples 2 and 5 had the worst performance.

[0130] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A stabilization treatment process for the wooden body of a woodwind musical instrument, characterized in that, Includes the following steps: S1. The wooden tube blank is subjected to hemicellulase treatment and C6~C18 alkenyl succinic anhydride treatment in sequence to obtain the first blank; S2. The first blank is first impregnated with the first resin liquid and then pre-cured to obtain the second blank; S3. Impregnate the second blank with the second resin solution to obtain the third blank; S4. The third blank is cured to obtain a stabilized wooden tube for a woodwind instrument. The first resin liquid comprises an epoxy resin with an epoxy equivalent of 180-220 and a hydroxyl-terminated polyurethane prepolymer; The second resin liquid includes epoxy resin, polyurethane prepolymer, nanocellulose whiskers, and hydroxyl-terminated polydimethylsiloxane.

2. The processing technology as described in claim 1, characterized in that, The hemicellulase mentioned in step S1 includes xylanase and / or mannanase.

3. The processing technology as described in claim 1, characterized in that, The curing process described in step S4 includes a gradient temperature curing process: first drying at 60~70℃ for 4~6 hours, then drying at 80~90℃ for 2~4 hours, and finally drying at 100~110℃ for 2~3 hours, with a heating rate ≤5℃ / h.

4. The processing technology as described in claim 3, characterized in that, Before the gradient temperature curing process described in step S4, the third blank is naturally air-dried for 24 to 48 hours.

5. The processing technology as described in claim 1, characterized in that, The step S1, which involves sequentially treating the wooden tube blank with hemicellulase and C6-C18 alkenyl succinic anhydride, includes: The wooden tube blank is placed in a reaction vessel and soaked in a hemicellulase solution for 1 to 3 hours. The concentration of the hemicellulase solution is 0.5% to 2%, the pH value is 5.0 to 6.0, and the temperature is 40 to 50°C. After draining the hemicellulase solution and washing with deionized water, an organic solution containing C6-C18 alkenyl succinic anhydride is injected and reacted for 2-5 hours. The mass fraction of the C6-C18 alkenyl succinic anhydride is 5%-15%, and the reaction temperature is 50-70℃. After the reaction is complete, the residual liquid is discharged, washed with ethanol, and dried at 55-65℃ until the water content is 10%-15%.

6. The processing technology as described in claim 5, characterized in that, The organic solution containing C6-C18 alkenyl succinic anhydride also includes a catalyst; The catalyst comprises at least one of 4-dimethylaminopyridine, triethylamine, anhydrous sodium carbonate, or dicyclohexylcarbodiimide (DCC).

7. The processing technology as described in claim 1, characterized in that, The first resin solution impregnation step S2 includes: evacuating to -0.08 to -0.1 MPa and maintaining for 30 to 40 minutes, injecting the first resin solution and immersing under vacuum for 2 to 4 hours, and then pressurizing to 0.3 to 0.5 MPa and maintaining for 2 to 3 hours; The pre-curing conditions are 60~80℃ for 1~2 hours.

8. The processing technology as described in claim 1, characterized in that, The second resin solution impregnation step S3 includes: evacuating to -0.08 to -0.1 MPa and maintaining for 30 minutes, injecting the second resin solution and immersing under vacuum for 3 to 5 hours, and then pressurizing to 0.6 to 0.9 MPa and maintaining for 8 to 12 hours.

9. The processing technology as described in claim 1, characterized in that, In step S2, the first resin solution further includes methyltrimethoxysilane and anhydrous ethanol; The first resin liquid comprises, by weight, 40-60 parts of epoxy resin with an epoxy equivalent of 180-220, 20-30 parts of hydroxyl-terminated polyurethane prepolymer, 5-10 parts of methyltrimethoxysilane, and 10-20 parts of anhydrous ethanol.

10. The processing technology as described in claim 1, characterized in that, In step S3, the second resin solution also includes methyltrimethoxysilane, anhydrous ethanol, distilled water, bamboo vinegar, polyethylene glycol, and latent amine curing agent; The second resin liquid comprises, by weight: 40-50 parts epoxy resin, 20-30 parts polyurethane prepolymer, 1-3 parts nanocellulose whiskers, 2-4 parts hydroxyl-terminated polydimethylsiloxane, 5-8 parts methyltrimethoxysilane, 10-15 parts anhydrous ethanol, 5-8 parts distilled water, 3-5 parts bamboo vinegar, 4-6 parts polyethylene glycol, and 3-8 parts latent amine curing agent.

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