Method for preparing wood adhesive by using vinyl double-monomer modified gelatin

Abstract

The invention discloses a method for preparing a wood adhesive by using vinyl double-monomer modified gelatin. The method specifically comprises the following steps: preparing a gelatin aqueous solution and adjusting the pH value; the method comprises the following steps: dropwise adding a mixed solution of glycidyl methacrylate and glycidyl methacrylate into a gelatin aqueous solution, dropwise adding an initiator ammonium persulfate solution at the same time, and carrying out stirring reaction and cooling to obtain the wood adhesive. Vinyl of dimethylaminoethyl methacrylate and a gelatin molecular chain are subjected to a free radical graft copolymerization reaction under the action of an initiator, covalent bonds are formed, and the cohesion strength of the adhesive is improved; amino groups and gelatin peptide bonds construct a dynamic cross-linked network through hydrogen bonds and electrostatic interaction, so that an adhesive layer is endowed with toughness. Meanwhile, glycidyl methacrylate is introduced, an epoxy group of glycidyl methacrylate and a gelatin hydroxyl group are subjected to a ring-opening reaction to generate ether bond covalent linkage, the bonding force of an adhesive layer and a wood interface is enhanced, and meanwhile, the adhesive synthesized by taking a biomass material collagen as a base material has good biodegradability.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesive material preparation, and particularly relates to a method for preparing wood adhesive by utilizing vinyl dimonomer-modified gelatin. Background Art

[0002] In the adhesive application field, traditional "trialdehyde" adhesives, due to the release of harmful substances such as formaldehyde, pose prominent problems such as environmental pollution, health risks, and restrictions on high-end applications. The leather industry is plagued by the difficulty of disposing of chromium-containing waste generated by the chrome tanning process. Over 90% of the raw biomass of hide and glue in this solid waste remains unutilized. Purification and hydrolysis of leather waste can produce high-polymer gelatin, which has natural viscosity and can be used as an adhesive raw material.

[0003] Common methods for preparing gelatin-based wood adhesives include the gelatin-formaldehyde method, the gelatin-glutaraldehyde method, the gelatin-tannic acid method, the gelatin-nanoparticle modification method, and the gelatin-polyvinyl alcohol (PVA) blending method. The gelatin-formaldehyde method offers high bonding strength, low cost, and a mature process, but contains toxic formaldehyde, is environmentally unfriendly, and easily releases formaldehyde at high temperatures. The gelatin-glutaraldehyde method crosslinks quickly, can be operated at room temperature, and has good water resistance, but glutaraldehyde is expensive and has a pungent odor, limiting its use in certain scenarios. The gelatin-tannic acid method is naturally non-toxic, biocompatible, and weather-resistant, but has low bonding strength, requires acidic conditions, and is applicable to limited wood materials. The gelatin-nanoparticle modification method can significantly enhance mechanical properties and improve water and heat resistance, but nanoparticle dispersion is difficult, the cost is high, and the process is complex. The gelatin-PVA blending method offers good toughness, uniform film formation, and low-temperature operation, but has poor water resistance, softens easily at high temperatures, and lacks long-term aging resistance. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a wood adhesive using vinyl dimonomer-modified gelatin, which significantly improves the cohesive strength and interfacial adhesion of the adhesive.

[0005] The technical solution adopted by the present invention is a method for preparing a wood adhesive using vinyl dimonomer-modified gelatin, which is specifically implemented according to the following steps: Step 1, preparation of gelatin aqueous solution; Step 2: adjusting the pH of the gelatin aqueous solution to 8-10 using a NaOH aqueous solution; Step 3: Add glycidyl methacrylate and a mixed solution of glycidyl methacrylate to the gelatin aqueous solution obtained in step 2, and simultaneously add an initiator ammonium persulfate solution. After the addition is complete, stir the mixture to react, and naturally cool to room temperature to obtain a wood adhesive.

[0006] The present invention is also characterized in that: In step 1, specifically: Disperse gelatin in distilled water and stir at 40-50°C for 20-30 minutes at a stirring speed of 150-200 r / min to form a uniform gelatin aqueous solution.

[0007] The mass fraction of the gelatin aqueous solution is 8% to 15%.

[0008] In step 3, the initiator is added at a rate of 3 mL / min, and the initiator is added within 10 to 30 minutes. In step 3, the stirring speed is 150-450 r / min, the reaction time is 1-2 h, and the reaction temperature is 70-78°C.

[0009] In step 3, the molar ratio of gelatin, glycidyl methacrylate, and glycidyl methacrylate is 2.0-5.0:0.5-5.0:1.0-3.0.

[0010] The amount of ammonium persulfate added is 0.1 to 1.1% of the total mass of glycidyl methacrylate and glycidyl methacrylate.

[0011] The beneficial effects of the present invention are: (1) In the method of the present invention, gelatin molecular chains release a large number of active groups (amino, carboxyl, etc.) through hydrolysis, and react with the vinyl groups of dimethylaminoethyl methacrylate (DMAEMA) and the epoxy groups of glycidyl methacrylate (GMA) through free radical copolymerization to form a multi-covalent cross-linked network, significantly improving the cohesive strength and interfacial adhesion of the adhesive, thereby greatly improving the bonding strength. The epoxy groups of GMA react with the hydroxyl and amino groups of gelatin to form hydrophobic ether bonds / amine bonds, reducing the penetration and swelling of water molecules into the adhesive layer; the quaternary ammonium structure of DMAEMA enhances the cross-linking density through ionic bonding, forming a water-resistant barrier, so that the adhesive maintains stable bonding performance in humid environments.

[0012] (2) In the method of the present invention, biomass collagen is used as the base material. No aldehyde-containing reagents are introduced during the entire synthesis process. The solvent used is water. The material is fixed through a green process, and the aldehyde-free property is fully guaranteed from the raw materials to the process. At the same time, the adhesive synthesized with biomass collagen as the base material has good biodegradability. In addition, the preparation process of the present invention is simple, the operation process is simple, the conditions are mild, and it is conducive to mass production; (3) The epoxy and amino groups in the wood adhesive prepared by the present invention have low activation energy and can undergo a ring-opening reaction at room temperature. These functional groups can form covalent bonds with the amino groups in the wood, while also achieving intermolecular bonding through hydrogen bonding and electrostatic interactions. This bonding mechanism based on chemical bonding is fundamentally different from the physical bonding principle of traditional adhesives that rely on solvent evaporation to form mechanical interlocking. It breaks through the traditional reliance on high temperatures and can be bonded at room temperature, eliminating the need for high-temperature heating equipment, reducing energy consumption, lowering costs, and simplifying the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is an optical photograph of the adhesive sample; Figure 2 is the infrared spectrum of the adhesive sample; Figure 3 The shear strength diagram of different types of adhesives; Figure 4 The biodegradability diagram of different types of adhesives; Figure 5 The biodegradation rate diagram of different types of adhesives; Figure 6 This is the shear strength diagram of the adhesive at different curing times at room temperature; Figure 7 is the particle size distribution diagram of the adhesive emulsion; Figure 8 TEM image of the adhesive emulsion. DETAILED DESCRIPTION

[0014] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] The method of preparing a wood adhesive using vinyl dimonomer-modified gelatin is specifically implemented according to the following steps: Step 1. Preparation of gelatin aqueous solution: Disperse gelatin in distilled water and stir at 40-50°C for 20-30 minutes at a stirring speed of 150-200 r / min to completely dissolve the gelatin and form a uniform gelatin aqueous solution; the concentration of the gelatin aqueous solution is 8%-15%; Step 2, adjusting the pH of the gelatin aqueous solution: using a 10% by mass NaOH aqueous solution to adjust the pH of the gelatin aqueous solution to 8-10; Step 3, preparation of wood adhesive: add a mixed solution of glycidyl methacrylate (GMA) and glycidyl methacrylate (DMAEMA) dropwise to the gelatin aqueous solution obtained in step 2, and simultaneously add an initiator ammonium persulfate solution dropwise, control the initiator addition rate to 3 mL / min, and drip the initiator within 10-30 minutes. After the dripping is completed, stir the reaction at a stirring speed of 150-450 r / min, a reaction time of 1-2 hours, and a reaction temperature of 70-78°C. Under the above conditions, allow the graft copolymerization reaction to proceed fully, and then naturally cool to room temperature to obtain an adhesive product.

[0016] The molar ratio of gelatin, glycidyl methacrylate (GMA), and glycidyl methacrylate (DMAEMA) is 2.0-5.0:0.5-5.0:1.0-3.0; The amount of ammonium persulfate added is 0.1-1.1% of the total mass of glycidyl methacrylate and glycidyl methacrylate; The method of the invention utilizes amino groups, epoxy groups and other groups in vinyl monomers to carry out graft copolymerization modification on gelatin extracted from waste leather scraps to prepare an environmentally friendly, high-strength, low-temperature curing wood adhesive.

[0017] Example 1 The method of preparing a wood adhesive using vinyl dimonomer-modified gelatin is specifically implemented according to the following steps: (1) Preparing a gelatin hydrolyzate solution; Disperse gelatin in distilled water and stir at 40°C for 30 min at a stirring speed of 150 r / min to completely dissolve the gelatin and form a uniform solution with a concentration of 9%.

[0018] (2) Adjustment of the pH of the gelatin aqueous solution: Use a 10% mass fraction of NaOH aqueous solution to adjust the solution pH to 8; (3) Add a mixed solution of glycidyl methacrylate and dimethylaminoethyl methacrylate to the gelatin aqueous solution with adjusted pH, and simultaneously add a 0.1% ammonium persulfate solution (based on the total weight of the monomers) within 10 minutes. After the addition is complete, maintain the stirring speed at 150 r / min and continue the reaction for 1 hour at a reaction temperature of 78°C to allow the graft copolymerization reaction to proceed fully. A high-strength adhesive (GDG) is obtained through one-pot copolymerization. The molar ratio of gelatin, glycidyl methacrylate and dimethylaminoethyl methacrylate is 2:1:1.

[0019] Example 2 The method of preparing a wood adhesive using vinyl dimonomer-modified gelatin is specifically implemented according to the following steps: (1) Preparing a gelatin hydrolyzate solution; Disperse gelatin in distilled water and stir at 50°C for 20 min at a stirring speed of 200 r / min to completely dissolve the gelatin and form a uniform solution with a concentration of 10%.

[0020] (2) Adjustment of the pH of the gelatin aqueous solution: The pH of the mixture was adjusted to 9 using a 10% by mass NaOH aqueous solution.

[0021] (3) Into the pH-adjusted gelatin aqueous solution, a mixed solution of glycidyl methacrylate and dimethylaminoethyl methacrylate was added dropwise at one end, and a 0.3% ammonium persulfate solution (equivalent to the total weight of the monomer) was added dropwise at the other end. Simultaneously with the monomer addition, the ammonium persulfate solution was added dropwise, and the addition rate was controlled to complete the addition within 20 min. After the addition was completed, the stirring speed was maintained at 200 r / min and the reaction was continued for 2 h at a reaction temperature of 70 °C to allow the graft copolymerization reaction to proceed fully. A high-strength adhesive (GDG) was obtained by one-pot copolymerization.

[0022] The molar ratio of gelatin, glycidyl methacrylate (GMA), and dimethylaminoethyl methacrylate (DMAEMA) is 3:1:1.

[0023] Example 3 The method of preparing a wood adhesive using vinyl dimonomer-modified gelatin is specifically implemented according to the following steps: (1) Preparing a gelatin hydrolyzate solution; Disperse gelatin in distilled water and stir at 50°C for 30 min at a stirring speed of 200 r / min to completely dissolve the gelatin and form a uniform solution with a concentration of 11%.

[0024] (2) Adjustment of the pH of the gelatin aqueous solution: The pH of the mixture was adjusted to 10 using a 10% by mass NaOH aqueous solution.

[0025] (3) Into the pH-adjusted gelatin aqueous solution, a mixed solution of glycidyl methacrylate and dimethylaminoethyl methacrylate was added dropwise at one end, and a 0.5% ammonium persulfate solution (based on the total weight of the monomer) was added dropwise at the other end. While the monomer was being added, the ammonium persulfate solution was also added dropwise, and the addition rate was controlled to ensure that the solution was added within 30 min. After the addition was complete, the stirring speed was maintained at 300 r / min and the reaction was continued for 2 h at a temperature of 72 °C to allow the graft copolymerization reaction to proceed fully. A high-strength adhesive (GDG) was obtained through one-pot copolymerization.

[0026] The molar ratio of gelatin, glycidyl methacrylate, and dimethylaminoethyl methacrylate (DMAEMA) is 2:2:2.

[0027] Example 4 The method of preparing a wood adhesive using vinyl dimonomer-modified gelatin is specifically implemented according to the following steps: (1) Preparing a gelatin hydrolyzate solution; Disperse gelatin in distilled water and stir at 50°C for 30 min at a stirring speed of 200 r / min to completely dissolve the gelatin and form a uniform solution with a concentration of 8%.

[0028] (2) Adjustment of the pH of the gelatin aqueous solution: The pH of the mixture was adjusted to 10 using a 10% by mass NaOH aqueous solution.

[0029] (3) Into the pH-adjusted gelatin aqueous solution, a mixed solution of glycidyl methacrylate and dimethylaminoethyl methacrylate was added dropwise at one end, and a 0.7% ammonium persulfate solution (based on the total weight of the monomer) was added dropwise at the other end. Simultaneously with the monomer addition, the ammonium persulfate solution was added dropwise, and the addition rate was controlled to ensure that the solution was added within 30 min. After the addition was complete, the stirring speed was maintained at 300 r / min and the reaction was continued for 3 h at a temperature of 74 °C to allow the graft copolymerization reaction to proceed fully. A high-strength adhesive (GDG) was obtained through one-pot copolymerization.

[0030] The molar ratio of gelatin, glycidyl methacrylate (GMA), and dimethylaminoethyl methacrylate (DMAEMA) is 3:2:3.

[0031] Example 5 (1) Preparing a gelatin hydrolyzate solution; Disperse gelatin in distilled water and stir at 50°C for 30 min at a stirring speed of 200 r / min to completely dissolve the gelatin and form a uniform solution with a concentration of 12%.

[0032] (2) Adjustment of the pH of the gelatin aqueous solution: The pH of the mixture was adjusted to 9 using a 10% by mass NaOH aqueous solution.

[0033] (3) Into the pH-adjusted gelatin aqueous solution, a mixed solution of glycidyl methacrylate and dimethylaminoethyl methacrylate was added dropwise at one end, and 0.9% of the total weight of the monomer as an ammonium persulfate initiator was added dropwise at the other end. Simultaneously with the monomer addition, the ammonium persulfate solution was added dropwise, and the addition rate was controlled to ensure that the addition was completed within 30 min. After the addition was completed, the stirring speed was maintained at 350 r / min and the reaction was continued for 4 h at a reaction temperature of 76°C to allow the graft copolymerization reaction to proceed fully. A high-strength adhesive (GDG) was obtained through one-pot copolymerization.

[0034] The molar ratio of gelatin, glycidyl methacrylate and dimethylaminoethyl methacrylate is 3:1:3.

[0035] Example 6 The method of preparing a wood adhesive using vinyl dimonomer-modified gelatin is specifically implemented according to the following steps: (1) Preparing a gelatin hydrolyzate solution; Disperse gelatin in distilled water and stir at 50°C for 30 min at a stirring speed of 200 r / min to completely dissolve the gelatin and form a uniform solution with a concentration of 10%.

[0036] (2) Adjustment of the pH of the gelatin aqueous solution: The pH of the mixture was adjusted to 9 using a 10% by mass NaOH aqueous solution.

[0037] (3) Into the pH-adjusted gelatin aqueous solution, a mixed solution of glycidyl methacrylate and dimethylaminoethyl methacrylate was added dropwise at one end, and 1.1% of the total weight of the monomer as an ammonium persulfate initiator was added dropwise at the other end. While the monomer was being added, the ammonium persulfate solution was also added dropwise, and the addition rate was controlled to ensure that the solution was added within 30 min. After the addition was completed, the stirring speed was maintained at 350 r / min and the reaction was continued for 5 h at a reaction temperature of 70°C to allow the graft copolymerization reaction to proceed fully. A high-strength adhesive (GDG) was obtained through one-pot copolymerization.

[0038] The molar ratio of gelatin, glycidyl methacrylate and dimethylaminoethyl methacrylate is 5:3:3.

[0039] Figure 1 This is an optical photograph of the adhesive sample prepared in Example 2. The image shows that the adhesive is in an emulsion state, with a bluish, uniform distribution. A homogeneous emulsion indicates a stable dispersion, with well-mixed components and no significant agglomeration or precipitation. This facilitates uniform coating and consistent bonding when used as a wood adhesive. The bluish hue indicates that the dispersed phase particle size in the emulsion is in the relatively small colloidal range. This particle size imparts good fluidity and permeability to the emulsion, facilitating its penetration into wood pores for effective bonding.

[0040] Figure 2 The infrared spectrum of the wood adhesive prepared in Example 2 is shown in the figure. As can be seen from the figure, at 3423 cm -1 At 2949 cm -1 The absorption peaks of symmetric and asymmetric stretching vibration of -CH2 are at 1722 cm -1 Nearby, there are C=O stretching vibration absorption peaks from diaminoethyl methacrylate (DMAEMA) and glycidyl methacrylate. At 1662 cm -1 It is the characteristic absorption peak of amide I band (C=O stretching vibration) in gelatin. -1is the bending vibration peak of saturated CH at 1550 cm -1 It is the characteristic absorption peak of amide II band (N-H bending vibration), at 1249 cm -1 It is the characteristic absorption peak of amide III band (C-N and N-H stretching vibration), at 1170 cm -1 It is the vibration absorption peak of C-O in the ester group, at 951cm -1 The peak at 1640 cm is the characteristic peak of epoxy group deformation vibration. -1 The absorption peak of the carbon-carbon double bond disappears, indicating that the double bond is broken and the monomer participates in the reaction. In summary, the analysis of each characteristic peak corresponds to the structural characteristics of the monomer, proving that the corresponding target product is generated.

[0041] Figure 3 The figure shows the shear strength of different adhesive types. The adhesive prepared in Example 2 has a shear strength of 7.3 MPa, the all-purpose glue has a shear strength of 4.2 MPa, the 502 glue has a shear strength of 5.7 MPa, and the phenolic glue has a shear strength of 1.2 MPa. These adhesives exhibit 73.8% and 28.1% improvements over the all-purpose glue and 502 glue, respectively. This is primarily due to the fact that the amino, carboxyl, hydroxyl, epoxy, and cationic groups in the adhesive structure react with carboxyl and hydroxyl groups in the wood, forming covalent bonds, hydrogen bonds, ionic bonds, and mechanical anchoring. These groups can then cross-link tightly with the wood to form a multi-layered network structure, thereby enhancing its adhesive properties.

[0042] Figure 4 and Figure 5 The following are graphs showing the biodegradability of different types of adhesives. This experimental study compared the degradation performance of commercially available phenolic glue and the adhesive prepared in Example 2 over a period of seven days. During the observation period, the commercially available phenolic glue remained relatively stable from day one to day seven. Although the glue blocks showed some changes in the soil, they remained clearly discernible, indicating that its degradation rate was extremely slow. This is because phenolic glue is a traditional synthetic adhesive with a stable chemical structure and strong resistance to degradation, making it difficult for microorganisms to rapidly decompose it in the natural environment.

[0043] The adhesive prepared in Example 2, on the other hand, exhibited a markedly different performance. During the first few days (days 1 to 4), the appearance of the adhesive block changed slightly, but its presence remained recognizable. By the fifth day, the block began to show clear signs of decomposition, and plant growth in the surrounding soil was robust. This was primarily due to the nutrients released during the degradation of the biomass adhesive. By the seventh day, the block had almost completely degraded, and its presence in the soil was virtually nonexistent. This is due to the inherent biodegradability of the biomass collagen-based material, which, under the influence of soil microorganisms and environmental factors, rapidly decomposes into small molecules and incorporates into the soil. This characteristic not only addresses the persistent problem of traditional adhesives remaining in the soil and polluting the environment after disposal, but also provides the dual guarantee of "high-performance bonding + zero-pollution degradation" for industries such as wood processing and furniture manufacturing. In summary, biomass collagen-based adhesives significantly outperform commercially available phenolic adhesives in terms of degradation performance and are expected to play an important role in environmentally sensitive fields such as ecological restoration and biodegradable packaging.

[0044] Figure 6 It is the shear strength of the adhesive prepared by Example 2 at different curing times under room temperature. As can be seen from the figure, as the room temperature curing time progressively increases from 1 hour, shear strength presents a trend of continuous rise. In the initial stage, i.e. from 1 hour to 4 hours, the shear strength rises relatively slowly, progressively increases from about 3.9MPa to about 5.5MPa, which shows that in this time period, the curing reaction inside the adhesive is ongoing, but the reaction rate is relatively stable. When the curing time is advanced to 6 hours from 4 hours, the shear strength rising speed is accelerated, and is promoted to more than 6.1MPa from about 5.5MPa, indicating that this stage curing reaction is accelerated, and the adhesive internal structure is further optimized, and bonding performance is significantly enhanced. After the curing time reaches 7 hours, the shear strength reaches about 6.9MPa, and remains stable substantially at 7-8 hours, which means that the adhesive substantially completes the curing process in about 7 hours, and the internal structure tends to be stable, and continuing to extend the curing time is no longer obvious to the effect of shear strength promotion. In summary, room temperature curing time significantly affects the shear strength of adhesives. Extending the curing time within a certain range can effectively improve shear strength, but beyond a certain time (approximately 7 hours), further extensions have no effect. In practical applications, this principle can be used to rationally control the curing time to achieve ideal bonding performance while improving production efficiency.

[0045] This invention uses a free radical graft copolymerization reaction between the vinyl groups of dimethylaminoethyl methacrylate (DMAEMA) and gelatin molecular chains under the action of an initiator to form covalent bonds, enhancing the adhesive's cohesive strength. The amino groups in DMAEMA form a dynamic crosslinking network with the gelatin peptide bonds through hydrogen bonding and electrostatic interactions, imparting toughness to the adhesive layer. Furthermore, the introduction of glycidyl methacrylate (GMA) allows its epoxy groups to undergo a ring-opening reaction with the gelatin hydroxyl groups to form covalent ether bonds, strengthening the adhesive layer's adhesion to the wood interface. The hydrophobic methyl and ester groups in both groups block the gelatin's polar groups, reducing water intrusion, improving water resistance, and enabling low-temperature curing. Furthermore, the adhesive, based on the biomass material collagen, exhibits excellent biodegradability.

[0046] Figure 7 This is the particle size distribution of the adhesive emulsion prepared by the method of the present invention. As can be seen from the figure, the particle size of the emulsion with a mass fraction of 0.5% adhesive is concentrated between 50 and 255 nm, exhibiting a generally normal distribution, with an average particle size of 111 nm. This indicates that the average particle size of this system is very small, with a PDI of 0.346, indicating a relatively narrow particle size distribution and relatively uniform particle size, demonstrating good monodispersity.

[0047] Figure 8 This is a TEM image of the adhesive emulsion (magnification 50000×), which clearly shows the morphological characteristics of the emulsion particles from a microscopic perspective and provides intuitive microscopic evidence for the particle size distribution. As can be seen from the figure, the adhesive emulsion particles appear to be relatively regular or irregular spherical or quasi-spherical water-in-oil micelles. The particle size of the emulsion particles is mainly distributed around 100nm, which is consistent with the Figure 7 The results are largely consistent with those in

[15] . The narrow particle size distribution and moderate average particle size impart excellent fluidity to the emulsion, enabling it to spread more efficiently and evenly across the wood surface during the gluing process, deeply penetrating the wood's micropore structure and achieving close contact and good wetting with the wood surface, laying the foundation for a strong bonding interface. Furthermore, the uniform particle state enhances the stability of the emulsion system, effectively reducing particle agglomeration and sedimentation during storage and use, ensuring consistent and reliable adhesive performance, thereby improving the quality and durability of the wood bond.

Claims

1. A method for preparing a wood adhesive using vinyl dimonomer-modified gelatin, characterized in that: Please follow the steps below to implement it: Step 1, preparation of gelatin aqueous solution; Step 2: adjusting the pH of the gelatin aqueous solution to 8-10 using a NaOH aqueous solution; Step 3: Add glycidyl methacrylate and a mixed solution of glycidyl methacrylate to the gelatin aqueous solution obtained in step 2, and simultaneously add an initiator ammonium persulfate solution. After the addition is complete, stir the mixture to react, and naturally cool to room temperature to obtain a wood adhesive.

2. The method for preparing a wood adhesive using vinyl dimonomer-modified gelatin as claimed in claim 1, wherein: In the step 1, specifically: Disperse gelatin in distilled water and stir at 40-50°C for 20-30 minutes at a stirring speed of 150-200 r / min to form a uniform gelatin aqueous solution.

3. The method for preparing a wood adhesive using vinyl dimonomer-modified gelatin as claimed in claim 2, wherein: The mass fraction of the gelatin aqueous solution is 8% to 15%.

4. The method for preparing a wood adhesive using vinyl dimonomer-modified gelatin as claimed in claim 1, wherein: In step 3, the initiator is added at a rate of 3 mL / min, and the initiator is added within 10 to 30 minutes.

5. The method for preparing a wood adhesive using vinyl dimonomer-modified gelatin as claimed in claim 1, wherein: In step 3, the stirring speed is 150-450 r / min, the reaction time is 1-2 h, and the reaction temperature is 70-78° C.

6. The method for preparing a wood adhesive using vinyl dimonomer-modified gelatin as claimed in claim 1, wherein: In the step 3, the molar ratio of gelatin, glycidyl methacrylate, and glycidyl methacrylate is 2.0-5.0:0.5-5.0:1.0-3.

0.

7. The method for preparing a wood adhesive using vinyl dimonomer-modified gelatin as claimed in claim 1, wherein: The amount of ammonium persulfate added is 0.1 to 1.1% of the total mass of glycidyl methacrylate and glycidyl methacrylate.

8. The wood adhesive prepared by the method according to any one of claims 1 to 7.

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