High-solid-content fast-curing cake protein adhesive, preparation method thereof and application of adhesive in artificial boards

Abstract

The invention discloses a high-solid-content fast-curing cake protein adhesive, a preparation method thereof and application of the adhesive in artificial boards. The adhesive comprises the following raw materials: a component A, a component B, a curing agent and an initiator, wherein the component A comprises the following raw materials: N, N-dihydroxyethyl aniline; a compound containing a 4-aminophenyl group; ammonia triethylene tetramine; biphenyl dicarboxaldehyde; the raw material of the component B comprises vegetable protein. The adhesive disclosed by the invention is an adhesive which is high in solid content and can be rapidly cured. Wherein the component A is an organic-like covalent framework material and has the characteristics of porosity and covalent connection, and an interpenetrating and interlocking structure is realized by utilizing the porosity characteristic of the component A and natural pores in the crosslinking component B, so that the adhesive material disclosed by the invention has super-strong adhesiveness and stability.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, in particular to a high-solid content fast-curing cake protein adhesive and a preparation method thereof and application thereof in artificial boards. Background Art

[0002] Adhesive is a substance that combines different materials together through physical or chemical action. It can achieve a lasting bond through adhesion without changing the surface structure of the adherend. The ingredients of adhesives usually include resins, solvents, plasticizers and curing agents. Depending on the purpose, adhesives are widely used in many industries such as packaging, construction, electronics, automobiles and furniture manufacturing.

[0003] In recent years, meal protein adhesives, as a new type of natural polymer material, have gradually attracted widespread attention. This adhesive is mainly made of meal protein, which comes from plants, such as soybeans, rapeseed and other oil crops, which are byproducts of pressing. Meal protein is rich in protein and has good adhesion properties. It is a natural and environmentally friendly material. Compared with traditional synthetic adhesives, meal protein adhesives are not only biodegradable, but also can effectively reduce dependence on petroleum resources, which meets the current needs of sustainable development.

[0004] The advantages of meal protein adhesives are first reflected in their excellent adhesion. Meal protein molecules have strong hydrophilicity and adhesion ability, and can undergo physical adsorption or chemical reaction with the surfaces of various substrates to achieve a strong connection. In addition, meal protein raw materials are widely available and low-cost, and the preparation process is environmentally friendly, which not only reduces dependence on traditional chemical adhesives, but also reduces production costs. In terms of environmental protection, the biodegradability of meal protein adhesives makes it an ideal green alternative material, reducing the burden on the environment.

[0005] However, cake protein adhesives are still facing some technical bottlenecks, especially in terms of solid content and viscosity. Solid content is an important indicator to measure the performance of adhesives, which determines the bonding strength and drying speed of adhesives. Adhesives with low solid content are prone to slow evaporation of water during use, thus affecting the improvement of bonding strength. Viscosity affects the workability of adhesives. Too low viscosity may make the adhesive difficult to control during use, or even cause flowing. Therefore, how to increase the solid content and viscosity of cake protein adhesives while ensuring environmental protection and degradability is a problem that needs to be solved urgently.

[0006] In addition, the curing process of traditional water-based adhesives is often slow. It usually takes a long time for water to evaporate, which consumes energy and affects production efficiency. For composite materials such as bamboo and wood particleboard, the curing process of traditional adhesives is not only long, but also often has the problem of uneven curing, which leads to unstable performance of the final product. Traditional adhesives have poor compatibility with bamboo and wood particleboard substrates and often cannot effectively form a strong bond, resulting in insufficient bonding strength of the board. At the same time, they have strong water absorption and are prone to swelling and deformation.

[0007] To address these issues, there is an urgent need to develop high-solid content, fast-curing adhesives to effectively improve the stability of related products including bamboo and wood particleboards. Summary of the invention

[0008] The object of the present invention is to provide an adhesive with high solid content and capable of rapid curing.

[0009] A first aspect of the present invention is:

[0010] An adhesive is provided.

[0011] A second aspect of the present invention is:

[0012] Provided is a method for preparing an adhesive.

[0013] The third aspect of the present invention is:

[0014] Application of the adhesive.

[0015] Specifically, the technical solution adopted according to the first aspect of the present invention is:

[0016] An adhesive, the raw materials of the adhesive include component A, component B, a curing agent and an initiator:

[0017] The raw materials of component A include the following components:

[0018] N,N-dihydroxyethylaniline;

[0019] Compounds containing a 4-aminophenyl group;

[0020] Triethylenetetramine;

[0021] Biphenyl dicarboxaldehyde;

[0022] The raw material of component B includes plant protein.

[0023] According to the embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0024] The adhesive of the present invention is an adhesive with high solid content and can be cured quickly. Among them, component A of the present invention is a kind of organic covalent framework material with porous and covalently connected characteristics. The porous characteristics of component A are used to cross-link the natural pores in component B to achieve an interpenetrating and interlocking structure, so that the adhesive material of the present invention has super strong adhesion and stability.

[0025] Specifically, in component A, N,N-dihydroxyethylaniline contains two hydroxyl structures and a benzene ring structure, and has high reactivity, and the compound containing a 4-aminophenyl group has multiple amino groups; the compound containing a 4-aminophenyl group, biphenyldicarboxaldehyde and N,N-dihydroxyethylaniline undergo a hydroxylamine condensation reaction under certain conditions to form a covalent bond. Due to the presence of the polymer containing a 4-aminophenyl group, the component A is a COFs-like structure product with ultra-large molecular pores, good hydrophilicity and water solubility, and can achieve a high solid content, and the adhesive of the present invention has the beneficial effects of high reactivity and fast curing speed.

[0026] Each component compound of the adhesive of the present invention contains a large number of hydrophilic groups such as hydroxyl groups and amino groups. The ratio of plant protein in component A and component B can achieve a high solid content (solid content 60-70%), and the viscosity is moderate, which is suitable for large-scale production applications. High solid content is a necessary condition for rapid curing. High solid content means lower water content, and the time for water volatilization by heat during thermal curing is shortened;

[0027] The COFs-like structure of component A has large molecular pores, and the large number of hydrophilic groups on the molecules can fix water in the pores. After component A and component B are fully blended, during the curing reaction, the COFs structure molecules and the long-chain component molecules react with each other, and a complete curing reaction can be achieved without completely evaporating the water. At the same time, the components have high reactivity, and within the conventional heating curing temperature range, the curing reaction time is shorter than that of other adhesives.

[0028] According to one embodiment of the present invention, triethylenetetramine is a small molecule compound containing four amino groups, and is a curing agent in the reaction, which can participate in the reaction (hydroxylamine condensation) and promote the rapid progress of the reaction.

[0029] According to one embodiment of the present invention, the weight ratio of component A to component B is 0.2-0.5:1-1.2.

[0030] According to one embodiment of the present invention, the raw materials of component A include the following components in parts by weight:

[0031] N,N-dihydroxyethylaniline, 10-40;

[0032] Compounds containing a 4-aminophenyl group, 10-50;

[0033] triethylenetetramine ammonia, 2-5;

[0034] Biphenyl dicarboxaldehyde, 20-80.

[0035] According to one embodiment of the present invention, the compound containing a 4-aminophenyl group includes at least one of tetrakis(4-aminophenyl)methane and 1,3,5-tris(4-aminophenyl)benzene.

[0036] According to one embodiment of the present invention, the plant protein comprises at least one of tung oil cake protein, camellia oil cake protein, soybean protein, soybean cake protein and litsea cubeba cake protein. Preferably, the plant protein comprises one of camellia oil cake protein and soybean cake protein.

[0037] According to one embodiment of the present invention, the plant protein is a modified plant protein, and the modified plant protein is obtained by treating the plant protein with urea and / or an alkaline agent. The protein macromolecules of the plant protein are in a curled state as a whole, and are not macromolecular long-chain structures. By treating with urea and / or an alkaline agent, the protein macromolecules can be unrolled and unfolded to present a long-chain macromolecular state, and during the treatment process, the protein macromolecules are degraded to a certain extent, so that some active groups (amino, carboxyl, hydroxyl, thiol, etc.) are fully exposed, especially the thiol groups on the long-chain protein molecules, to participate in subsequent reactions.

[0038] In addition, plant protein also has a higher water solubility after modification, which can further increase the solid content of the adhesive. High solid content is a necessary condition for rapid curing. High solid content means lower water content, and the time for water volatilization during thermal curing is shortened.

[0039] According to one embodiment of the present invention, the method for preparing the modified plant protein comprises the following steps: mixing 2% by mass of urea and 25% by mass of plant protein in water, and continuously stirring for 0.5-1h to obtain the modified plant protein.

[0040] According to one embodiment of the present invention, the plant protein includes at least one of tung oil cake protein, camellia oil cake protein, soybean protein, soybean cake protein and litsea cubeba cake protein.

[0041] Specifically, the technical solution adopted according to the second aspect of the present invention is:

[0042] A method for preparing the adhesive comprises the following steps:

[0043] S1: mixing N,N-dihydroxyethylaniline, a part of the compound containing 4-aminophenyl group and triethylenetetramine, heating and reacting in a protective atmosphere to obtain a prepolymer;

[0044] S2: mixing the prepolymer, biphenyl dicarboxaldehyde and the remaining amount of the compound containing a 4-aminophenyl group in a solvent, heating and reacting in a protective atmosphere to obtain component A;

[0045] S3: mixing component A, component B, a curing agent and an initiator to obtain the adhesive.

[0046] According to the embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0047] The present invention generates a prepolymer through a hydroxylamine condensation reaction, and the prepolymer reacts with biphenyl dicarboxaldehyde and a compound containing a 4-aminophenyl group to generate a cross-linking component A. The component A has a large number of irregular porous structures, and a large number of hydrophilic groups contained in the molecule can fix water in the pores. During the reaction with the component B, it is not necessary to completely volatilize and remove the water, so that the water in the pores of the adhesive can be used as a reaction medium, and the adhesive can be quickly cured;

[0048] According to one embodiment of the present invention, in step S2, the heating further includes the following steps: oil bath heating and condensation reflux.

[0049] According to one embodiment of the present invention, in step S2, the temperature of the oil bath heating is 110-140°C.

[0050] According to one embodiment of the present invention, the curing agent includes GY-051 condensation amine curing agent.

[0051] According to one embodiment of the present invention, the initiator comprises a peroxide initiator.

[0052] Another aspect of the present invention further provides an artificial board, including the adhesive as described in the embodiment of the first aspect. Since the application adopts all the technical solutions of the above adhesive, it has at least all the beneficial effects brought by the technical solutions of the above embodiment.

[0053] According to one embodiment of the present invention, the artificial board comprises a bamboo particle board.

[0054] According to one embodiment of the present invention, the bamboo particle board is a board with a thickness of 2 to 8 mm. The raw material is shavings, the length of the shavings is 0.8 to 4 mm, the thickness is 0.2 to 0.25 mm, and the aspect ratio is about 15 mm.

[0055] According to one embodiment of the present invention, the bamboo particle board can replace plywood and be used as a furniture bottom board, a partition board, and can also be used as a core board of plywood.

[0056] According to one embodiment of the present invention, the preparation of the bamboo particleboard includes the steps of mixing the adhesive of the present invention with the shavings and performing hot pressing.

[0057] According to one embodiment of the present invention, the hot pressing temperature is 100-110°C.

[0058] According to one embodiment of the present invention, the hot pressing time is 100 to 180 seconds.

[0059] According to one embodiment of the present invention, the hot pressing pressure is 0.8-1.2 MPa.

[0060] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0061] The words "preferred", "more preferred" and the like in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0062] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0063] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0064] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0065] Example 1

[0066] An adhesive, the raw materials include component A and component B in a weight ratio of 0.2:1, and also include a curing agent and an initiator:

[0067] The raw materials of component A include the following components in parts by weight:

[0068] N,N-dihydroxyethylaniline, 20 parts;

[0069] Tetrakis(4-aminophenyl)methane, 40 parts;

[0070] Triethylenetetramine, 2 parts;

[0071] Biphenyl dicarboxaldehyde, 30 parts;

[0072] The raw material of component B includes plant protein.

[0073] A method for preparing the adhesive comprises the following steps:

[0074] S1 20 parts of N,N-dihydroxyethylaniline, 40 parts of tetrakis(4-aminophenyl)methane and 2 parts of triethylenetetramine were stirred evenly, heated to 60°C in a nitrogen atmosphere, and reacted for 15 minutes to obtain a prepolymer;

[0075] S2 prepolymer and 30 parts of biphenyl dicarboxaldehyde were mixed in anhydrous dioxane, heated to 1250°C in an oil bath in a nitrogen atmosphere, condensed and refluxed, and continuously stirred rapidly. After reacting for 10 hours, a solid product was obtained. The solid product was washed with acetone and tetrahydrofuran, freeze-dried for 72 hours, and ground and passed through a 200-mesh sieve to obtain component A;

[0076] S3: Mix component A, component B, GY-051 condensation amine curing agent, water and initiator, and stir for 1 hour to obtain the adhesive.

[0077] Example 2

[0078] The difference between Example 2 and Example 1 is that the compound containing 4-aminophenyl group in Example 2 includes 1,3,5-tris(4-aminophenyl)benzene.

[0079] Specific:

[0080] An adhesive, the raw materials include component A and component B in a weight ratio of 0.2:1, and also include a curing agent and an initiator:

[0081] The raw materials of component A include the following components in parts by weight:

[0082] N,N-dihydroxyethylaniline, 20 parts;

[0083] 1,3,5-tris(4-aminophenyl)benzene, 40 parts;

[0084] Triethylenetetramine, 2 parts;

[0085] Biphenyl dicarboxaldehyde, 30 parts;

[0086] The raw material of component B includes plant protein.

[0087] A method for preparing the adhesive comprises the following steps:

[0088] S1 20 parts of N,N-dihydroxyethylaniline, 40 parts of 1,3,5-tris(4-aminophenyl)benzene and 2 parts of triethylenetetramine were stirred evenly, heated to 60°C in a nitrogen atmosphere, and reacted for 15 minutes to obtain a prepolymer;

[0089] S2 prepolymer and 30 parts of biphenyl dicarboxaldehyde were mixed in anhydrous dioxane, heated to 1250°C in an oil bath in a nitrogen atmosphere, condensed and refluxed, and continuously stirred rapidly. After reacting for 10 hours, a solid product was obtained. The solid product was washed with acetone and tetrahydrofuran, freeze-dried for 72 hours, and ground and passed through a 200-mesh sieve to obtain component A;

[0090] S3: Mix component A, component B, GY-051 condensation amine curing agent, water and initiator, and stir for 1 hour to obtain the adhesive.

[0091] Example 3

[0092] The difference between Example 3 and Example 1 is that the weight ratio of component A to component B in Example 3 is 0.5:1.

[0093] Specific:

[0094] An adhesive, the raw materials include component A and component B in a weight ratio of 0.5:1, and also include a curing agent and an initiator:

[0095] The raw materials of component A include the following components in parts by weight:

[0096] N,N-dihydroxyethylaniline, 20 parts;

[0097] Tetrakis(4-aminophenyl)methane, 40 parts;

[0098] Triethylenetetramine, 2 parts;

[0099] Biphenyl dicarboxaldehyde, 30 parts;

[0100] The raw material of component B includes plant protein.

[0101] A method for preparing the adhesive comprises the following steps:

[0102] S1 20 parts of N,N-dihydroxyethylaniline, 40 parts of tetrakis(4-aminophenyl)methane and 2 parts of triethylenetetramine were stirred evenly, heated to 60°C in a nitrogen atmosphere, and reacted for 15 minutes to obtain a prepolymer;

[0103] S2 prepolymer and 30 parts of biphenyl dicarboxaldehyde were mixed in anhydrous dioxane, heated to 1250°C in an oil bath in a nitrogen atmosphere, condensed and refluxed, and continuously stirred rapidly. After reacting for 10 hours, a solid product was obtained. The solid product was washed with acetone and tetrahydrofuran, freeze-dried for 72 hours, and ground and passed through a 200-mesh sieve to obtain component A;

[0104] S3: Mix component A, component B, GY-051 condensation amine curing agent, water and initiator, and stir for 1 hour to obtain the adhesive.

[0105] Example 4

[0106] The difference between Example 4 and Example 1 is that in Example 4, the amount of N,N-dihydroxyethylaniline component used is different, that is, 5 parts.

[0107] Specific:

[0108] An adhesive, the raw materials include component A and component B in a weight ratio of 0.2:1, and also include a curing agent and an initiator:

[0109] The raw materials of component A include the following components in parts by weight:

[0110] N,N-dihydroxyethylaniline, 5 parts;

[0111] Tetrakis(4-aminophenyl)methane, 40 parts;

[0112] Triethylenetetramine, 2 parts;

[0113] Biphenyl dicarboxaldehyde, 30 parts;

[0114] The raw material of component B includes plant protein.

[0115] A method for preparing the adhesive comprises the following steps:

[0116] S1 5 parts of N,N-dihydroxyethylaniline, 40 parts of tetrakis(4-aminophenyl)methane and 2 parts of triethylenetetramine were stirred evenly, heated to 60°C in a nitrogen atmosphere, and reacted for 15 minutes to obtain a prepolymer;

[0117] S2 prepolymer and 30 parts of biphenyl dicarboxaldehyde were mixed in anhydrous dioxane, heated to 1250°C in an oil bath in a nitrogen atmosphere, condensed and refluxed, and continuously stirred rapidly. After reacting for 10 hours, a solid product was obtained. The solid product was washed with acetone and tetrahydrofuran, freeze-dried for 72 hours, and ground and passed through a 200-mesh sieve to obtain component A;

[0118] S3: Mix component A, component B, GY-051 condensation amine curing agent, water and initiator, and stir for 1-2 hours to obtain the adhesive.

[0119] Example 5

[0120] The difference between Example 5 and Example 1 is that in Example 5, the amount of tetrakis(4-aminophenyl)methane component used is different, that is, 30 parts.

[0121] Specific:

[0122] An adhesive, the raw materials include component A and component B in a weight ratio of 0.2:1, and also include a curing agent and an initiator:

[0123] The raw materials of component A include the following components in parts by weight:

[0124] N,N-dihydroxyethylaniline, 20 parts;

[0125] Tetrakis(4-aminophenyl)methane, 30 parts;

[0126] Triethylenetetramine, 2 parts;

[0127] Biphenyl dicarboxaldehyde, 30 parts;

[0128] The raw material of component B includes plant protein.

[0129] A method for preparing the adhesive comprises the following steps:

[0130] S1 20 parts of N,N-dihydroxyethylaniline, 30 parts of tetrakis(4-aminophenyl)methane and 2 parts of triethylenetetramine were stirred evenly, heated to 60°C in a nitrogen atmosphere, and reacted for 15 minutes to obtain a prepolymer;

[0131] S2 prepolymer and 30 parts of biphenyl dicarboxaldehyde were mixed in anhydrous dioxane, heated to 1250°C in an oil bath in a nitrogen atmosphere, condensed and refluxed, and continuously stirred rapidly. After reacting for 10 hours, a solid product was obtained. The solid product was washed with acetone and tetrahydrofuran, freeze-dried for 72 hours, and ground and passed through a 200-mesh sieve to obtain component A;

[0132] S3: Mix component A, component B, GY-051 condensation amine curing agent, water and initiator, and stir for 1-2 hours to obtain the adhesive.

[0133] Example 6

[0134] The difference between Example 6 and Example 1 is that in Example 6, the amount of the biphenyl dicarboxaldehyde raw material component is different, which is 20 parts.

[0135] Specific:

[0136] An adhesive, the raw materials include component A and component B in a weight ratio of 0.2:1, and also include a curing agent and an initiator:

[0137] The raw materials of component A include the following components in parts by weight:

[0138] N,N-dihydroxyethylaniline, 20 parts;

[0139] Tetrakis(4-aminophenyl)methane, 40 parts;

[0140] Triethylenetetramine, 2 parts;

[0141] Biphenyl dicarboxaldehyde, 20 parts;

[0142] The raw material of component B includes plant protein.

[0143] A method for preparing the adhesive comprises the following steps:

[0144] S1 20 parts of N,N-dihydroxyethylaniline, 40 parts of tetrakis(4-aminophenyl)methane and 2 parts of triethylenetetramine were stirred evenly, heated to 60°C in a nitrogen atmosphere, and reacted for 15 minutes to obtain a prepolymer;

[0145] S2 prepolymer and 20 parts of biphenyl dicarboxaldehyde were mixed in anhydrous dioxane, heated to 1250°C in an oil bath in a nitrogen atmosphere, condensed and refluxed, and stirred rapidly continuously. After reacting for 10 hours, a solid product was obtained. The solid product was washed with acetone and tetrahydrofuran, freeze-dried for 72 hours, and ground and passed through a 200-mesh sieve to obtain component A;

[0146] S3: Mix component A, component B, GY-051 condensation amine curing agent, water and initiator, and stir for 1-2 hours to obtain the adhesive.

[0147] Comparative Example 1

[0148] The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, N,N-dihydroxyethylaniline is replaced by catecholamine.

[0149] Comparative Example 2

[0150] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, tetrakis(4-aminophenyl)methane is replaced by p-phenylenediamine.

[0151] Comparative Example 3

[0152] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, biphenyl dicarboxaldehyde is replaced by terephthalaldehyde.

[0153] Performance Test:

[0154] The adhesives prepared in Examples 1-6 and Comparative Examples 1-3 were further prepared into thin bamboo particle boards, and the performance of the thin bamboo particle boards was tested. The test results are shown in Table 1.

[0155] Thin bamboo particleboard thin particleboard refers to the board with a thickness of 6 mm, the raw material length is 0.8-4 mm, the thickness is 0.2-0.25 mm. Using a thickness gauge with a thickness of 6 mm, the flat pressing method is used to prepare a board with a length, width and thickness of 600 mm × 600 mm × 6 mm for testing.

[0156] Table 1 Performance test of thin particle board

[0157]

[0158] In Comparative Example 1, N,N-dihydroxyethylaniline is replaced by catecholamine. Although both have hydroxyl and benzene ring structures and two hydroxyl groups in the structure, N,N-dihydroxyethylaniline has two hydroxyl groups connected to the amino group, and its reactivity is higher than that of catecholamine. In the reaction of step S1, catecholamine cannot react with tetrakis(4-aminophenyl)methane and triethylenetetramine in the reaction, so it is a simple blend, resulting in the inability to form a cross-linked network structure in the form of covalent bonds during the thermal curing process, and it cannot react with the protein component, so that its physical and mechanical properties are worse than those of Example 1. At the same time, the components cannot react and exist in a blended form. During the curing process, the self-polymerization of the protein component is mainly the main factor, resulting in a significant increase in the curing time.

[0159] In Comparative Example 2, tetrakis(4-aminophenyl)methane is replaced by p-phenylenediamine, both of which contain amino groups, but tetrakis(4-aminophenyl)methane contains four amino groups, has a high spatial structure, can fully participate in the reaction and extend the chain outward to form a macroporous structure, and p-phenylenediamine has a small molecular structure, although it has a certain reactivity, but compared with tetrakis(4-aminophenyl)methane, the reactivity is weak, and the chain cannot be fully extended during the reaction to form a macroporous structure, so that compared with Example 1, the physical and mechanical properties are weaker. At the same time, due to incomplete reaction of each component, most of the components exist in a blended form. During the curing process, the self-polymerization of the protein component is mainly the main, and a very small part of the prepolymer reacts with each other as a supplement, resulting in a significant increase in the curing time compared with Example 1.

[0160] In Comparative Example 3, biphenyldicarboxaldehyde is replaced by terephthalaldehyde, both of which contain 2 aldehyde groups, but the difference in structure is large, and the biphenyldicarboxaldehyde aldehyde group is distributed on two benzene rings, has a higher spatial structure, and the reactivity is also higher, and can fully participate in the reaction and outward chain extension to form a macroporous structure. And the terephthalaldehyde molecular structure is small, and belongs to a planar structure in the spatial structure, and the contrast biphenyldicarboxaldehyde, the reactivity is weaker, and it is impossible to fully extend the chain in space and form a macroporous structure during the reaction process, so that compared with Example 1, physical and mechanical properties are all weaker. Meanwhile, each component is incomplete because of the reaction, and most of the components exist in a blended form, and in the curing process, mainly based on the self-polymerization of the protein component, causing the curing time to be significantly increased compared with Example 1.

[0161] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An adhesive, characterized in that: The raw materials of the adhesive include component A, component B, a curing agent and an initiator: The raw materials of component A include the following components: N,N-dihydroxyethylaniline; Compounds containing a 4-aminophenyl group; Triethylenetetramine ammonia; Biphenyl dicarboxaldehyde; The raw material of component B includes plant protein.

2. An adhesive according to claim 1, characterized in that: The weight ratio of component A to component B is 0.2-0.5:1-1.

2.

3. An adhesive according to claim 1, characterized in that: The raw materials of component A include the following components in parts by weight: N,N-dihydroxyethylaniline, 10-40; Compounds containing a 4-aminophenyl group, 10-50; triethylenetetramine ammonia, 2-5; Biphenyl dicarboxaldehyde, 20-80.

4. An adhesive according to claim 1, characterized in that: The compound containing a 4-aminophenyl group includes at least one of tetrakis(4-aminophenyl)methane and 1,3,5-tris(4-aminophenyl)benzene.

5. An adhesive according to claim 1, characterized in that: The vegetable protein is a modified vegetable protein obtained by treating the vegetable protein with urea and / or an alkaline agent.

6. An adhesive according to claim 5, characterized in that: The plant protein comprises at least one of tung oil cake protein, camellia oil cake protein, soybean protein, soybean cake protein and litsea cubeba cake protein.

7. A method for preparing an adhesive as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1: mixing N,N-dihydroxyethylaniline, a part of the compound containing 4-aminophenyl group and triethylenetetramine, heating and reacting in a protective atmosphere to obtain a prepolymer; S2: mixing the prepolymer, biphenyl dicarboxaldehyde and the remaining amount of the compound containing a 4-aminophenyl group in a solvent, heating and reacting in a protective atmosphere to obtain component A; S3: mixing component A, component B, a curing agent and an initiator to obtain the adhesive.

8. The method according to claim 7, characterized in that: In step S2, the heating further comprises the following steps: oil bath heating and condensation reflux.

9. The method according to claim 8, characterized in that: In step S2, the temperature of the oil bath heating is 110-140°C.

10. A wood-based panel, characterized in that: The artificial board comprises an adhesive as described in any one of claims 1 to 6.

Images