A cake meal protein-based adhesive and a preparation method and application thereof

Abstract

The application discloses a cake-separation protein-based adhesive as well as a preparation method and application thereof, and relates to the technical field of adhesives.The adhesive is prepared from the following components: trifuran formaldehyde diimine, a carbonyl compound, cake-separation protein, furan amine, an ester compound, a curing agent, an initiator and water.The adhesive has good mechanical properties, high water resistance and fast curing.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, and in particular to a cake protein isolate-based adhesive, its preparation method, and its application. Background Technology

[0002] Oilseed cake protein isolate refers to the protein component extracted from the oilseed cake of vegetable oil crops, primarily soybeans, peanuts, and rapeseed. After oil extraction, the remaining material is the oilseed cake, which itself contains a certain proportion of plant protein. Traditionally, oilseed cake is used as animal feed or fertilizer. However, with technological advancements, the protein in oilseed cake, due to its unique biochemical properties and excellent adhesive properties, has begun to be widely studied and applied in industrial production, especially in the field of adhesives. Oilseed cake protein isolate is not only a renewable biological resource but also possesses biodegradability and high environmental friendliness, meeting today's societal demand for green and environmentally friendly practices.

[0003] Adhesives, as the name suggests, are materials used to bond two or more substances together. They achieve adhesion through physical adsorption, chemical reaction, or a combination of both. There are many types of adhesives, which can be classified according to their origin as natural adhesives, synthetic adhesives, and bio-based adhesives. Among these, bio-based adhesives have gained increasing popularity in recent years, especially due to their advantages in environmental protection and sustainable development. Bio-based adhesives are typically composed of polymers derived from natural plants or animals. These adhesives not only possess excellent bonding properties but also degrade naturally after use, avoiding the environmental pollution caused by traditional synthetic adhesives.

[0004] However, despite the wide variety of adhesives available on the market, insufficient bonding strength remains a problem, especially in applications requiring high mechanical stress or high temperature and humidity. The bonding strength of an adhesive directly affects its reliability and durability in practical applications. Many natural and bio-based adhesives, while environmentally friendly, often exhibit low bonding strength due to their molecular structure, particularly in extreme environments such as humidity or high temperatures, where they are prone to losing their adhesive properties. Therefore, improving the bonding strength of adhesives and enhancing their temperature and humidity resistance has become a significant technical challenge in adhesive research.

[0005] Engineered wood products (AWD) are man-made materials made from wood fibers, plant fibers, or other non-wood raw materials through physical and chemical processing and then bonded together using adhesives. They are widely used in furniture manufacturing, construction, and decoration. The emergence of AWD has solved the problem of wood resource shortages and also provided the construction and home furnishing industries with a wider range of lower-cost material options. Common AWD types include particleboard, MDF, and plywood. Adhesives play a crucial role in the manufacturing process of AWD. Adhesives not only bond the fibers within the board but also ensure the board's stability, strength, and durability. The quality of the adhesive directly determines the overall performance of the AWD, especially in terms of compressive strength, flexural strength, and impact resistance.

[0006] With increasing emphasis on environmental protection and sustainable development, bio-based adhesives have gradually become a research focus in the engineered wood products industry. In traditional engineered wood products production, most adhesives are chemically synthesized. While these adhesives provide sufficient bond strength, they typically contain harmful volatile organic compounds (VOCs). These chemical components can impact air quality and human health during production and use. Therefore, developing low-VOC, non-toxic, and high-performance bio-based adhesives has become a current technological requirement for the engineered wood products industry.

[0007] Oilseed cake protein isolate adhesive, as a novel bio-based adhesive, possesses environmental advantages such as low toxicity, low VOC emissions, and biodegradability, while effectively meeting the bonding strength requirements of engineered wood products production. The protein molecules in oilseed cake have a certain degree of adhesiveness, allowing them to form strong bonds with other materials under appropriate conditions. This protein adhesive not only significantly reduces environmental pollution during engineered wood product production but also reduces dependence on petroleum-based chemicals, thereby reducing the consumption of non-renewable resources.

[0008] Currently, challenges remain in the practical application of protein oilseed meal isolate-based adhesives. First, although protein oilseed meal isolate possesses certain adhesive properties, achieving high strength comparable to traditional synthetic adhesives still requires modification and formulation optimization to improve its performance. Summary of the Invention

[0009] The purpose of this invention is to provide an adhesive with good mechanical properties, strong water resistance, and rapid curing.

[0010] The first aspect of the present invention is:

[0011] An adhesive is provided.

[0012] The second aspect of the present invention is as follows:

[0013] A method for preparing an adhesive is provided.

[0014] The third aspect of the present invention is:

[0015] The application of the adhesive.

[0016] The present invention also proposes an artificial board.

[0017] Specifically, the technical solution adopted according to the first aspect of the present invention is as follows:

[0018] An adhesive, wherein the raw materials of the adhesive comprise the following components:

[0019] Trifuran-formaldehyde diimide;

[0020] Carbonyl compounds;

[0021] Oilseed cake protein isolate;

[0022] furfurylamine;

[0023] Ester compounds;

[0024] Curing agent;

[0025] Initiator;

[0026] water.

[0027] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0028] The adhesive of the present invention is an adhesive with good mechanical properties, strong water resistance and rapid curing.

[0029] The molecular structure of the trifurancarbaldehyde diimide has three branches, which can effectively extend the chain in the condensation reaction to form a cross-linked network structure. In addition, the trifurancarbaldehyde diimide has high reactivity and can react with carbonyl compounds to quickly generate a polymer modifier with high reactivity through the condensation reaction. This polymer modifier can react with the active groups on the protein isolate macromolecule and subsequent related substances to form a unique molecular network structure.

[0030] As a small molecule compound, furfurylamine in this invention can undergo free radical polymerization with itself, the lignin component in bamboo and wood components, the hydroxyl groups on the macromolecular chains of oilseed meal isolates, the heterocycles in ester compounds, and the oxygen heterocycles in the structure of the polymer modifier, covalently linking multiple components and thereby improving the curing speed of the adhesive. In addition, furfurylamine itself can undergo a certain degree of condensation to form multiple cross-linked interpenetrating network structures, fully fixing multiple easily degradable and easily hydrolyzed components in the cross-linked interpenetrating network structures, thereby improving the mechanical properties of the adhesive.

[0031] An initiator initiates an olefin condensation reaction between ester compounds and other raw material components. Through various condensation and polymerization reactions, multiple interpenetrating cross-linked network structures are formed. These structures interpenetrate and are covalently linked to each other. The covalent bond formation reaction significantly consumes and reduces hydrophilic groups, thereby enhancing the mechanical properties while significantly reducing the hydrophilicity of the adhesive and improving its water resistance.

[0032] According to one embodiment of the present invention, the raw materials of the adhesive comprise the following components in parts by weight:

[0033] Trifuran-formaldehyde diimide;

[0034] Carbonyl compounds;

[0035] Oilseed cake protein isolate;

[0036] furfurylamine;

[0037] Ester compounds;

[0038] Curing agent;

[0039] Initiator;

[0040] water.

[0041] According to one embodiment of the present invention, the carbonyl compound includes glyoxal.

[0042] According to one embodiment of the present invention, the ester compound includes at least one of tetrahydrofurfuryl methacrylate and furfuryl methacrylate.

[0043] According to one embodiment of the present invention, the initiator includes a peroxide initiator.

[0044] According to one embodiment of the present invention, the initiator includes at least one of ammonium persulfate and potassium persulfate.

[0045] According to one embodiment of the present invention, the oilseed cake protein isolate includes at least one of tung oil cake meal, camellia oil cake meal, soybean cake meal, and litsea cubeba cake meal.

[0046] According to one embodiment of the present invention, the oilseed meal isolate is a modified oilseed meal isolate, obtained by modifying oilseed meal protein with urea and / or an alkaline reagent. Preferably, the modified oilseed meal isolate is obtained by modifying oilseed meal protein with urea.

[0047] According to one embodiment of the present invention, the method for preparing the modified oilseed meal isolate includes the following steps: mixing 2-3% urea and 25-30% oilseed meal plant protein by mass in water, and continuously stirring for 0.5-1 hour to obtain the modified oilseed meal isolate. Preferably, the method for preparing the modified oilseed meal isolate includes the following steps: mixing 2% urea and 25% oilseed meal plant protein by mass in water, and continuously stirring for 0.5-1 hour to obtain the modified oilseed meal isolate.

[0048] According to one embodiment of the present invention, the curing agent comprises GY-051 amine curing agent.

[0049] Specifically, the technical solution adopted according to the second aspect of the present invention is as follows:

[0050] A method for preparing the adhesive includes the following steps:

[0051] S1 is mixed with trifuranaldehyde diimide and carbonyl compounds in water, and the mixture is heated to react and obtain a modifier;

[0052] S2 mixes the modifier, oilseed meal isolate, furfurylamine, ester compounds, curing agent and initiator to obtain the adhesive.

[0053] According to one embodiment of the present invention, in step S1, the temperature of the heating reaction is 60-80°C.

[0054] According to one embodiment of the present invention, in step S1, the heating reaction time is 1-2 hours.

[0055] According to one embodiment of the present invention, in step S1, the heating reaction step includes heating and reflux.

[0056] According to one embodiment of the present invention, step S2 further includes the following steps: after mixing the modifier, oilseed meal isolate, furfurylamine, ester compound, curing agent, and initiator to obtain a mixture, adjusting the pH of the mixture to 3-5, and reacting to obtain the adhesive. pH affects the curing ability of the adhesive. When the pH is alkaline, the components of the adhesive cannot initiate a reaction during heating and cannot cure to form a cross-linked network structure; when the pH is acidic but not within the range of 3-5, the components also cannot cure to form a cross-linked network structure.

[0057] Another aspect of the present invention provides a engineered wood panel, comprising the adhesive described in the first aspect embodiment above. Since this application utilizes all the technical solutions of the aforementioned adhesive, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0058] According to one embodiment of the present invention, the engineered wood panel includes bamboo particleboard.

[0059] According to one embodiment of the present invention, the bamboo and wood particleboard is a board with a thickness of 2 to 8 mm. The raw material is wood shavings, the length of which is 0.8 to 4 mm, the thickness of which is 0.2 to 0.25 mm, and the aspect ratio of which is about 15 mm.

[0060] According to one embodiment of the present invention, the bamboo and wood particleboard can replace plywood as a furniture baseboard or partition, and can also be used as the core board of plywood.

[0061] According to one embodiment of the present invention, the bamboo and wood particleboard is prepared by a step of mixing the adhesive of the present invention with wood shavings and hot pressing them together.

[0062] According to one embodiment of the present invention, the hot pressing temperature is 100-110°C.

[0063] According to one embodiment of the present invention, the hot pressing time is 100-180 seconds.

[0064] According to one embodiment of the present invention, the hot pressing pressure is 0.8 to 1.2 MPa.

[0065] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Detailed Implementation

[0066] The terms "preferred," "more preferred," etc., used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0067] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0068] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of the present invention.

[0069] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0070] The oilseed meal isolates in the examples and comparative examples are modified oilseed meal isolates. The preparation method of the modified oilseed meal isolates includes the following steps: mixing 2% urea and 25% oilseed meal plant protein by mass in water, and continuously stirring for 1 hour to obtain the modified oilseed meal isolates.

[0071] In the examples and comparative examples, the initiator was potassium persulfate.

[0072] Example 1

[0073] An adhesive, wherein the raw materials of the adhesive comprise the following components in parts by weight:

[0074] Trifuran-formaldehyde diimide, 12 parts;

[0075] Carbonyl compounds, 10 parts;

[0076] Protein isolate from meal, 30 portions;

[0077] Furfural, 6 parts;

[0078] Ester compounds, 10 parts;

[0079] Hardener, 2 parts;

[0080] Initiator, 1 part;

[0081] Water, 60 portions.

[0082] The aforementioned ester compound is tetrahydrofurfuryl methacrylate;

[0083] The carbonyl compound mentioned above is glyoxal.

[0084] The method for preparing the above-mentioned adhesive includes the following steps:

[0085] S1 is mixed with trifuran-formaldehyde diimide and glyoxal in water and reacted under reflux and stirring at 80°C for 1 hour to obtain the modifier;

[0086] S2 mixes the modifier, oilseed meal isolate, furfurylamine, ester compounds, curing agent and initiator, and adjusts the pH to 3 to obtain the adhesive.

[0087] Example 2

[0088] The difference between Example 2 and Example 1 is that the ester compound in Example 2 is furfuryl methacrylate.

[0089] Specifically:

[0090] An adhesive, wherein the raw materials of the adhesive comprise the following components in parts by weight:

[0091] Trifuran-formaldehyde diimide, 12 parts;

[0092] Glyoxal, 10 parts;

[0093] Protein isolate from meal, 30 portions;

[0094] Furfural, 6 parts;

[0095] Carbonyl compounds, 10 parts;

[0096] Hardener, 2 parts;

[0097] Initiator, 1 part;

[0098] Water, 60 portions.

[0099] The aforementioned ester compound is furfuryl methacrylate;

[0100] The carbonyl compound mentioned above is glyoxal.

[0101] The method for preparing the above-mentioned adhesive includes the following steps:

[0102] S1 is mixed with trifuran-formaldehyde diimide and glyoxal in water and reacted under reflux and stirring at 80°C for 1 hour to obtain the modifier;

[0103] S2 mixes the modifier, oilseed meal isolate, furfurylamine, ester compounds, curing agent and initiator, and adjusts the pH to 3 to obtain the adhesive.

[0104] Example 3

[0105] The difference between Example 3 and Example 1 is that the carbonyl compound is malondialdehyde.

[0106] Specifically:

[0107] An adhesive, wherein the raw materials of the adhesive comprise the following components in parts by weight:

[0108] Trifuran-formaldehyde diimide, 12 parts;

[0109] Carbonyl compounds, 10 parts;

[0110] Protein isolate from meal, 30 portions;

[0111] Furfural, 6 parts;

[0112] Ester compounds, 10 parts;

[0113] Hardener, 2 parts;

[0114] Initiator, 1 part;

[0115] Water, 60 portions.

[0116] The aforementioned ester compound is tetrahydrofurfuryl methacrylate;

[0117] The carbonyl compound mentioned above is malondialdehyde.

[0118] The method for preparing the above-mentioned adhesive includes the following steps:

[0119] S1 is mixed with trifuranaldehyde diimide and malondialdehyde in water and reacted under reflux and stirring at 80°C for 1 hour to obtain the modifier;

[0120] S2 mixes the modifier, oilseed meal isolate, furfurylamine, ester compounds, curing agent and initiator, and adjusts the pH to 3 to obtain the adhesive.

[0121] Example 4

[0122] The difference between Example 4 and Example 1 is that the amount of trifuran-formaldehyde diimide is different, which is 5 parts.

[0123] Specifically:

[0124] An adhesive, wherein the raw materials of the adhesive comprise the following components in parts by weight:

[0125] Trifuran-formaldehyde diimide, 5 parts;

[0126] Carbonyl compounds, 10 parts;

[0127] Protein isolate from meal, 30 portions;

[0128] Furfural, 6 parts;

[0129] Ester compounds, 10 parts;

[0130] Hardener, 2 parts;

[0131] Initiator, 1 part;

[0132] Water, 60 portions.

[0133] The aforementioned ester compound is tetrahydrofurfuryl methacrylate;

[0134] The carbonyl compound mentioned above is glyoxal.

[0135] The method for preparing the above-mentioned adhesive includes the following steps:

[0136] S1 is mixed with trifuran-formaldehyde diimide and glyoxal in water and reacted under reflux and stirring at 80°C for 1 hour to obtain the modifier;

[0137] S2 mixes the modifier, oilseed meal isolate, furfurylamine, ester compounds, curing agent and initiator, and adjusts the pH to 3 to obtain the adhesive.

[0138] Example 5

[0139] The difference between Example 5 and Example 1 is that the amount of furfurylamine used is different, at 15 parts.

[0140] Specifically:

[0141] An adhesive, wherein the raw materials of the adhesive comprise the following components in parts by weight:

[0142] Trifuran-formaldehyde diimide, 12 parts;

[0143] Carbonyl compounds, 10 parts;

[0144] Protein isolate from meal, 30 portions;

[0145] Furfural, 15 parts;

[0146] Ester compounds, 10 parts;

[0147] Hardener, 2 parts;

[0148] Initiator, 1 part;

[0149] Water, 60 portions.

[0150] The aforementioned ester compound is tetrahydrofurfuryl methacrylate;

[0151] The carbonyl compound mentioned above is glyoxal.

[0152] The method for preparing the above-mentioned adhesive includes the following steps:

[0153] S1 is mixed with trifuran-formaldehyde diimide and glyoxal in water and reacted under reflux and stirring at 80°C for 1 hour to obtain the modifier;

[0154] S2 mixes the modifier, oilseed meal isolate, furfurylamine, ester compounds, curing agent and initiator, and adjusts the pH to 3 to obtain the adhesive.

[0155] Comparative Example 1

[0156] The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, trifuranaldehyde diimide was replaced with furfural.

[0157] Comparative Example 2

[0158] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, furfurylamine is replaced with phenylethylamine.

[0159] Comparative Example 3

[0160] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, glyoxal is replaced with ethylene glycol. (Comparative Example 4)

[0161] The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, the ester compound is methacrylate.

[0162] Comparative Example 5

[0163] The difference between Comparative Example 5 and Example 1 is that the pH value of the adhesive in Comparative Example 5 is not 3, but 8.

[0164] Performance testing:

[0165] This test example evaluated the performance of bamboo-based engineered materials obtained in the comparative examples, and the test results are shown in Table 1. Preparation of lightweight bamboo-based engineered materials. Lightweight bamboo-based engineered materials refer to materials with a density lower than 1.0 g / cm³. 3 Reconstituted bamboo boards have a density greater than 1.0 g / cm³ compared to traditional boards. 3 The highest concentration can reach 1.2 g / cm³. 3 Excessive density severely impacts the ease of transportation, installation, and use of the board material. This paper aims to significantly reduce the board's density while maintaining stable board performance.

[0166] Table 1

[0167]

[0168]

[0169] In Comparative Example 1, trifuranaldehyde diimide was replaced with furfural. Both contain oxygen heterocyclic structures and aldehyde structures. Furfural itself is also a curing agent and can self-condense. However, furfural has weak reactivity with glyoxal, so modifier A could not be obtained, resulting in insufficient subsequent reactions. The resulting adhesive could not be fully cured during hot pressing and could not form a multi-interpenetrating network structure through the reaction between the components. This required high-pressure hot pressing, resulting in high density, poor mechanical properties, long curing time, and water absorption thickness expansion only reaching T15.0 grade (≤15%).

[0170] In Comparative Example 2, furfurylamine was replaced with phenylethylamine. Both contain amino groups, but their reactivity differs greatly. This is because furfurylamine reacts with other components through the amino group and the carbon on the heterocycle to form covalent bonds, while phenylethylamine only has an amino group and has very low reactivity with other components. The components are only blended and cannot be cured to form a cross-linked network structure. The resulting adhesive cannot be cured during hot pressing, making it impossible to hot press the board. The density, mechanical properties, water absorption thickness expansion and other properties cannot be detected.

[0171] In Comparative Example 3, glyoxal was replaced with ethylene glycol. The two have significantly different reactivity. Glyoxal reacts with the components through its aldehyde groups to form covalent bonds such as aldehyde-amine condensation and aldol condensation. Ethylene glycol, on the other hand, cannot participate in the reaction. The components are only blended and cannot be cured to form a cross-linked network structure. The resulting adhesive cannot be cured during hot pressing, making it impossible to hot press the board. The density, mechanical properties, water absorption thickness expansion and other properties cannot be detected.

[0172] In Comparative Example 4, the ester compound was methacrylate. The chemical structure of the methacrylate in Comparative Example 4 differed significantly from that of tetrahydrofurfuryl methacrylate or furfuryl methacrylate used in the examples. Tetrahydrofurfuryl methacrylate and furfuryl methacrylate contain tetrahydrofurfuryl and furfuryl groups, possessing two reactive groups. During the curing reaction, these two reactive groups can react with other components to form a multi-interpenetrating network structure and can also achieve their own chain extension reaction, thereby improving the physical properties of the adhesive and reducing the density of the board. Methacrylate, on the other hand, can only undergo its own polymerization reaction and cannot fully participate in the chemical reactions of other substances. Furthermore, it contains only monofunctional reactive groups, resulting in poor chain extension performance. This necessitates higher pressure hot pressing, leading to higher density, poorer mechanical properties, longer curing time, and a water absorption thickness expansion exceeding 15% in actual tests.

[0173] In Comparative Example 5, the pH value of the adhesive was not 3, but 8. pH value affects the curing ability of the adhesive. At a pH of 8, it is in an alkaline emulsion environment, and the components of the adhesive cannot react during heating, thus failing to cure and form a cross-linked network structure. Consequently, the resulting adhesive product cannot cure during hot pressing, making it impossible to hot press the board. Density, mechanical properties, and water absorption thickness expansion cannot be detected.

[0174] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An adhesive, characterized by: The raw materials of the adhesive include the following components by weight: trifuralyl formal diimine, 5-12 parts; a carbonyl compound, 3-10 parts, the carbonyl compound including at least one of glyoxal and malondialdehyde; cake separated protein, 20-40 parts; furfuryl amine, 5-15 parts; an ester compound, 10-18 parts, the ester compound including at least one of tetrahydrofurfuryl methacrylate and furfuryl methacrylate; a curing agent, 2-5 parts; an initiator, 0.5-2 parts; water, 50-80 parts; a preparation method of the adhesive, including the following steps: S1 mixing trifuralyl formal diimine and a carbonyl compound in water, and obtaining a modifier by heating reaction; S2 mixing the modifier, cake separated protein, furfuryl amine, an ester compound, a curing agent and an initiator, adjusting pH to 3-5, and obtaining the adhesive by reaction.

2. The adhesive according to claim 1, characterized in that: The initiator includes a peroxide initiator.

3. The adhesive of claim 1, wherein: The cake separated protein is modified cake separated protein, which is obtained by modifying cake protein with urea and / or an alkaline reagent.

4. A process for the preparation of an adhesive as claimed in any one of claims 1 to 3, characterised in that: including the following steps: S1 mixing trifuralyl formal diimine and a carbonyl compound in water, and obtaining a modifier by heating reaction; S2 mixing the modifier, cake separated protein, furfuryl amine, an ester compound, a curing agent and an initiator, adjusting pH to 3-5, and obtaining the adhesive by reaction.

5. A method according to claim 4, characterised in that: In step S1, the heating reaction is performed at a temperature of 60-80℃.

6. An engineered wood product, characterized by: The artificial board includes an adhesive as claimed in any one of claims 1 to 3.

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