Cake protein-based adhesive, preparation method thereof, and application thereof in bamboo artificial board

Abstract

The present invention discloses a cake protein-based adhesive, its preparation method, and its application in bamboo artificial panels. This relates to the technical field of adhesives. The adhesive comprises components A and B. Component A comprises the following: cellulose; phthalic anhydride polyester polyol; metaldehyde; and a first initiator; while component B comprises the following: plant protein; a hydroxyl compound; a second initiator; and water. The synergistic effect of components A and B results in a plant protein adhesive with high bond strength, mildew resistance, and corrosion resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, in particular to a cake protein-based adhesive and a preparation method thereof, and application thereof to bamboo artificial boards. Background Art

[0002] Adhesives are substances that can bond two or more materials together through physical or chemical action. Their basic function is to form a stable connection, making it difficult for the bonded materials to separate under external forces. Adhesives are widely used in industries such as construction, automotive, electronics, and furniture. Key types include hot melt adhesives, polyurethane adhesives, epoxy resin adhesives, and phenolic adhesives. Among them, plant protein adhesives are natural adhesives primarily composed of plant protein. Plant protein is derived from plants such as soybeans, wheat, and peas, and is extracted and modified. Plant protein adhesives are gaining increasing attention due to their environmental friendliness, non-toxicity, and biodegradability.

[0003] The advantages of plant protein adhesives are mainly reflected in several aspects. First, plant protein adhesives are renewable resources, reducing dependence on non-renewable resources such as petroleum. With the global emphasis on sustainable development and environmental protection, the application of plant protein as a renewable material in adhesives is particularly important. Secondly, plant protein adhesives do not release harmful volatile organic compounds (VOCs) during production and use, which greatly reduces the impact on the environment and human health. Compared with traditional synthetic adhesives, plant protein adhesives have obvious advantages in safety and environmental protection. Finally, the processing cost of plant protein adhesives is relatively low, suitable for large-scale applications, and has good market prospects.

[0004] However, existing plant protein adhesives still face several technical challenges. First, insufficient bonding strength is a major issue in the current application of plant protein adhesives. In many cases, the bonding strength of plant protein adhesives is inferior to that of synthetic adhesives, primarily due to the limitations of the molecular structure and polymerization state of plant protein. The bonding properties of plant protein may decline under the influence of environmental factors such as moisture content, temperature, and pH value. Furthermore, plant protein adhesives require the presence of water during the bonding process, and excessive moisture can weaken the bonding interface, further reducing the bonding strength.

[0005] Bamboo-based panels are made from bamboo or wood, processed into panels through physical or chemical methods. They are widely used in construction, furniture, flooring, and other fields. The choice of adhesive is crucial in the production of bamboo-based panels. Plant protein adhesives, as a new environmentally friendly material, offer significant advantages in bamboo-based panels. First, plant protein adhesives fully bond with bamboo and wood fibers, creating a good bond. Second, plant protein adhesives have excellent biocompatibility, helping to reduce the negative environmental impact of bamboo-based panels. Furthermore, bamboo-based panels produced using plant protein adhesives not only meet green and environmentally friendly product standards but also enhance their market competitiveness.

[0006] However, existing bamboo-based panels containing plant protein adhesives still lack adequate mildew resistance, corrosion resistance, static flexural strength, and flexural modulus. Plant protein itself is susceptible to microbial attack, and its water resistance and mildew resistance are poor, especially in humid environments, making the panels susceptible to mold and rot. Furthermore, due to the low degree of cross-linking in plant protein, the strength of the bonding interface is insufficient, which in turn affects static flexural strength and flexural modulus. These issues primarily stem from the limitations of plant protein's molecular structure and its inability to bind with other materials.

[0007] There is an urgent need to develop a plant protein adhesive that has advantages in bonding strength, mildew resistance, and corrosion resistance, so as to promote the further application and development of plant protein adhesives. Summary of the Invention

[0008] The purpose of the present invention is to develop a plant protein adhesive with high bonding strength and mildew and corrosion resistance.

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

[0010] An adhesive is provided.

[0011] The 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] The invention also provides a bamboo artificial board.

[0016] Specifically, the technical solution adopted according to the first aspect of the present invention is:

[0017] An adhesive, wherein the raw materials of the adhesive include component A and component B:

[0018] The component A comprises the following components:

[0019] cellulose;

[0020] Phthalic anhydride polyester polyol;

[0021] Metaldehyde;

[0022] a first initiator;

[0023] The component B comprises the following components:

[0024] Plant protein;

[0025] Hydroxyl compounds;

[0026] a second initiator;

[0027] water.

[0028] According to the embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0029] Metaldehyde reacts with the first initiator to form a terminal aldehyde compound through ring opening, and an active free radical is present at the terminal tail position, which has high reactivity. The terminal aldehyde compound connects cellulose and phthalic anhydride polyester polyol at both ends. Since cellulose and phthalic anhydride polyester polyol are both long-chain macromolecules with a large number of hydroxyl groups in their structures, the small molecule tetramolecular free radical can fully react with the hydroxyl groups on cellulose and phthalic anhydride polyester polyol to form a prepolymer. This prepolymer has a unique molecular structure and is stable in storage under room temperature conditions. It can react with the hydroxyl-rich component B under heating conditions. The connection between metaldehyde, cellulose and phthalic anhydride polyester polyol enables the formation of a double-crosslinked network morphology in the subsequent curing reaction, significantly enhancing water resistance and mechanical properties.

[0030] Under the action of the second initiator, the plant protein and the hydroxyl compound work together to form a more complex and stable cross-linked network. The introduction of the hydroxyl compound into the plant protein significantly increases the number of hydroxyl groups along the molecular chain, making the plant protein more exposed and more readily able to participate in subsequent reactions with the hydroxyl groups. The synergistic effect of Combination A and Component B results in the present adhesive being a plant protein adhesive with high bond strength and mildew and corrosion resistance.

[0031] According to one embodiment of the present invention, when other short-chain or branched similar substances are used to replace cellulose, the ring-opened paraformaldehyde will connect the replacement substances, and it is impossible to form a structure in which one end is connected to the replacement substance and the other end is connected to phthalic anhydride polyester polyol.

[0032] According to one embodiment of the present invention, when the adhesive of the present invention is to be used, component A and component B are blended to function.

[0033] According to one embodiment of the present invention, the component A comprises the following components in parts by weight:

[0034] Cellulose, 0.5-1.5 parts;

[0035] Phthalic anhydride polyester polyol, 5-8 parts;

[0036] Metaldehyde, 1 to 5 parts.

[0037] According to one embodiment of the present invention, the cellulose is preferably nanocellulose.

[0038] According to one embodiment of the present invention, in the component B, the weight ratio of the plant protein to the hydroxyl compound is 15-25:5-15.

[0039] 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.

[0040] 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 reagent. The present invention uses urea and / or an alkaline reagent to modify the plant protein. The original protein macromolecule is in a curled state as a whole, and has a non-macromolecular long-chain structure. Through the modification treatment with the above-mentioned chemical reagents, the protein macromolecule can be unwound and unfolded, presenting a long-chain macromolecular state, and during the treatment process, the protein macromolecule is degraded to a certain extent, so that some active groups (amino, carboxyl, hydroxyl, sulfhydryl, etc.) are fully exposed, especially the sulfhydryl groups on the long-chain protein molecules, to participate in subsequent reactions.

[0041] According to one embodiment of the present invention, the hydroxy compound includes at least one of isobutenol and allyl alcohol.

[0042] According to one embodiment of the present invention, the first initiator and the second initiator are independently selected from azobisisobutyronitrile or azobisisoheptanenitrile.

[0043] Specifically, the technical solution adopted according to the second aspect of the present invention is:

[0044] A method for preparing the adhesive comprises the following steps:

[0045] S1, under a protective atmosphere, mixing cellulose, phthalic anhydride polyester polyol, metaldehyde and a first initiator, heating and refluxing to obtain a modified nanocellulose prepolymer A;

[0046] S2: Mix the plant protein, the hydroxy compound and the second initiator in water, and heat and reflux to pretreat the protein component B;

[0047] S3: mixing the modified nanocellulose prepolymer A and the pretreated protein component B to obtain the adhesive.

[0048] According to one embodiment of the present invention, the protective atmosphere includes a nitrogen atmosphere.

[0049] According to one embodiment of the present invention, the heating temperature in step S1 is 90-100° C. and the heating time is 3-5 hours.

[0050] According to one embodiment of the present invention, the ratio of the heating temperature in step S1 to the heating temperature in step S2 is 90-100:60-80.

[0051] According to one embodiment of the present invention, the heating temperature in step S1 is 95-100°C.

[0052] According to one embodiment of the present invention, the heating time in step S1 is 3.5 to 4.5 hours.

[0053] According to one embodiment of the present invention, the heating temperature in step S2 is 60-80°C.

[0054] According to one embodiment of the present invention, the heating temperature in step S2 is 70-80°C.

[0055] According to one embodiment of the present invention, the heating time in step S2 is 50 to 80 minutes.

[0056] According to one embodiment of the present invention, the heating time in step S2 is 60 to 80 minutes.

[0057] Another aspect of the present invention provides a bamboo artificial board, comprising the adhesive described in the embodiment of the first aspect. Because this application utilizes all the technical solutions of the above-mentioned adhesive, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiment.

[0058] According to one embodiment of the present invention, the density of the bamboo artificial board is lower than 1.0 g / cm 3 The bamboo artificial board to which the adhesive of the present invention is applied can maintain the stability of the board performance and improve the mechanical and anti-corrosion and anti-mildew properties while significantly reducing the density of the board.

[0059] 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

[0060] In the description of the present invention, if there is a description of first, second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0061] The terms "preferably," "more preferably," and the like, used herein refer to embodiments of the present invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the reference to one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the present invention.

[0062] 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 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 a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed 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 embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts 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] In the examples and comparative examples, the plant protein is a modified plant protein, which is obtained by treating the plant protein with urea and / or an alkaline agent.

[0066] In the examples and comparative examples, the first initiator and the second initiator are respectively: azobisisobutyronitrile (AIBN) and azobisisoheptanenitrile (ABVN).

[0067] In the examples and comparative examples, the plant protein is camellia oil cake protein.

[0068] Example 1

[0069] An adhesive, wherein the raw materials of the adhesive include component A and component B in a weight ratio of 1:0.2:

[0070] The above-mentioned component A comprises the following components in parts by weight:

[0071] Nanocellulose, 1 part;

[0072] Phthalic anhydride polyester polyol, 6 parts;

[0073] Metaldehyde, 3 parts;

[0074] First initiator: 0.5 parts

[0075] The above-mentioned component B comprises the following components:

[0076] modified vegetable protein, 15 parts;

[0077] Isobutenol, 8 parts;

[0078] Second initiator, 0.8;

[0079] Water, 40 parts.

[0080] The method for preparing the above adhesive comprises the following steps:

[0081] S1, under a protective atmosphere, mixes nanocellulose, phthalic anhydride polyester polyol, metaldehyde and a first initiator, heats to 90°C under nitrogen protection and reflux treatment, and maintains the temperature for 3 hours to obtain a modified nanocellulose prepolymer A;

[0082] S2: Mix the plant protein, isobutenol and the second initiator in water, heat to 80°C under reflux conditions, and react for 80 minutes to obtain a pretreated protein component B;

[0083] S3: mixing the modified nanocellulose prepolymer A and the pretreated protein component B to obtain the adhesive.

[0084] Example 2

[0085] The difference between Example 2 and Example 1 is that in Example 2, the hydroxy compound is allyl alcohol.

[0086] Example 3

[0087] The difference between Example 3 and Example 1 is that in Example 3, the amount of metaldehyde used is 1 part.

[0088] Example 4

[0089] The difference between Example 4 and Example 1 is that in Example 4, the usage ratio of component A to component B is 1:0.5.

[0090] Example 5

[0091] The difference between Example 5 and Example 1 is that in Example 5, the heating temperature in step S1 is different and is 100°C.

[0092] Example 6

[0093] The difference between Example 6 and Example 1 is that in Example 6, the heating temperature in step S2 is different, that is, 80°C.

[0094] Comparative Example 1

[0095] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain phthalic anhydride polyester polyol.

[0096] Comparative Example 2

[0097] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, nanocellulose is replaced by starch.

[0098] Comparative Example 3

[0099] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, nanocellulose is replaced by glycerol.

[0100] Comparative Example 4

[0101] The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, phthalic anhydride polyester polyol is replaced by polycaprolactone polyol.

[0102] Comparative Example 5

[0103] The difference between Comparative Example 5 and Example 1 is that in Comparative Example 5, metaldehyde is replaced by polyoxymethylene.

[0104] Comparative Example 6

[0105] The difference between Comparative Example 6 and Example 1 is that in Comparative Example 6, metaldehyde is replaced by acetaldehyde.

[0106] Comparative Example 7

[0107] The difference between Comparative Example 7 and Example 1 is that Component A is not contained in Comparative Example 7.

[0108] Comparative Example 8

[0109] The difference between Comparative Example 8 and Example 1 is that in Comparative Example 8, phthalic anhydride polyester polyol is replaced by furfuryl alcohol resin.

[0110] Performance testing:

[0111] The adhesives prepared in Examples 1-7 and Comparative Examples 1-5 were used to prepare lightweight bamboo engineering materials to obtain bamboo artificial boards. The bamboo artificial boards were tested, and the results are shown in Table 1.

[0112] Table 1

[0113]

[0114]

[0115] As can be seen from Table 1, the difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain phthalic anhydride polyester polyol, resulting in component A in Comparative Example 1 being unable to react effectively, and no substantial reaction occurs even when blended with component B, so the resulting sheet cannot be formed.

[0116] Comparative Example 2 differs from Example 1 in that nanocellulose is replaced with starch in Comparative Example 2. Due to the weak reactivity of starch with other substances and the short starch molecules, although the -OH groups in starch can still undergo a certain grafting reaction with the phthalic anhydride polyester polyol, the subsequent curing reactivity with component B is poor, and an interpenetrating network structure cannot be effectively formed. As a result, the adhesive of Comparative Example 2 has poor bonding performance, requiring a higher density for the board to be formed, resulting in poor mildew resistance and corrosion resistance, as well as poor static bending strength and flexural modulus.

[0117] Comparative Example 3 differs from Example 1 in that nanocellulose is replaced with glycerol. This substitution of glycerol for nanocellulose weakens the reaction of component A and the curing reaction with component B, resulting in the inability to form an interpenetrating network structure. This weakens the bonding performance and prevents effective hot-pressing of the sheet material. This results in an inability to measure density and mechanical properties. Consequently, the sheet material exhibits poor corrosion and mildew resistance.

[0118] Comparative Example 4: Phthalic anhydride polyester polyol is replaced by polycaprolactone polyol. On the one hand, the molecular structure of polycaprolactone lacks rigid structural units such as benzene rings, which makes its hardness and rigidity lower, resulting in a decrease in the bending elastic modulus of the prepared bamboo artificial board; on the other hand, polycaprolactone polyol is composed of linear caprolactone units, which mainly interact with other molecular chains through weak van der Waals forces and hydrogen bonds, which makes the connection between its molecules relatively loose; and the presence of benzene rings and amide groups in phthalic anhydride polyester polyol makes it easier for phthalic anhydride polyester polyol molecules to react with functional groups such as amino groups and carboxyl groups in proteins through hydrogen bonds, π-π interactions or covalent bonds when in contact with proteins, thereby enhancing its compatibility and reactivity with proteins.

[0119] In Comparative Examples 5-6, compared with Example 1, the tetraacetaldehyde was replaced with polyoxymethylene or acetaldehyde. This resulted in no reaction between components A and only physical blending. No reaction occurred during the hot-curing of the mixed components with component B. As a result, there was no reaction during the hot-pressing process of the plate, and no actual hot-pressing was performed. As a result, the density and mechanical properties could not be tested, and the corrosion resistance and mildew resistance were poor.

[0120] The difference between Comparative Example 7 and Example 1 is that Comparative Example 7 does not contain component A. Comparative Example 7 is an adhesive system composed only of component B. During the hot pressing of the sheet, there is no curing reaction and no interpenetrating network structure is formed. Therefore, the density and mechanical properties cannot be tested.

[0121] Comparative Example 8 differs from Example 1 in that the phthalic anhydride polyester polyol is replaced with furfuryl alcohol resin in Comparative Example 8. Furfuryl alcohol resin requires an acidic catalyst to cure, and Comparative Example 8 lacks such a curing condition, so an adhesive cannot be synthesized.

[0122] The above are merely 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 and component B: The component A comprises the following components: cellulose; Phthalic anhydride polyester polyol; Metaldehyde; a first initiator; The component B comprises the following components: Plant protein, wherein the plant protein is a modified plant protein obtained by treating the plant protein with urea and / or an alkaline agent; Hydroxyl compounds; a second initiator; water.

2. The adhesive according to claim 1, characterized in that: The component A comprises the following components in parts by weight: Cellulose, 0.5-1.5 parts; Phthalic anhydride polyester polyol, 5-8 parts; Metaldehyde, 1 to 5 parts.

3. The adhesive according to claim 1, characterized in that: The hydroxy compound includes at least one of isobutylene alcohol and allyl alcohol.

4. The adhesive according to claim 1, characterized in that: In the component B, the weight ratio of the plant protein to the hydroxy compound is 15-25:5-15.

5. The adhesive according to claim 4, characterized in that: The plant protein comprises at least one of tung oil cake protein, camellia oil cake protein, soybean cake protein and litsea cubeba cake protein.

6. A method for preparing an adhesive according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Mixing cellulose, phthalic anhydride polyester polyol, metaldehyde and a first initiator under a protective atmosphere, heating and refluxing to obtain a modified nanocellulose prepolymer A; S2: mixing the plant protein, the hydroxy compound and the second initiator in water, heating and refluxing to pretreat the protein component B; S3: mixing the modified nanocellulose prepolymer A and the pretreated protein component B to obtain the adhesive.

7. The method according to claim 6, characterized in that: The heating temperature in step S1 is 90-100° C. and the heating time is 3-5 h.

8. A bamboo artificial board, characterized by: The bamboo artificial board comprises an adhesive as claimed in any one of claims 1 to 5.

9. The bamboo artificial board according to claim 8, characterized in that: The density of the bamboo artificial board is lower than 1.0 g / cm 3 .

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