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

Abstract

The invention discloses a cake protein-based adhesive, a preparation method thereof and application of a bamboo artificial board. Relates to the technical field of adhesives. The raw materials of the adhesive comprise a component A and a component B. The component A comprises the following component: cellulose; phthalic anhydride polyester polyol; metaldehyde; a first initiator; the component B comprises the following component: vegetable protein; a hydroxyl compound; a second initiator; and water. Under the synergistic effect of the composition A and the component B, the adhesive disclosed by the invention is a vegetable protein adhesive with high bonding strength and mildew-proof and corrosion-resistant properties.

Description

Technical Field

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

[0002] Adhesive is a substance that can combine two or more materials together through physical or chemical action. Its basic function is to form a stable connection so that the bonded materials are not easily separated under the action of external force. Adhesives are widely used in many industries including construction, automobiles, electronics, furniture, etc. Its main types include hot melt adhesives, polyurethane adhesives, epoxy resin adhesives, phenolic adhesives, etc. Among them, plant protein adhesives are a natural adhesive with plant protein as the main ingredient. Plant protein comes from plants such as soybeans, wheat, and peas, and is prepared by extraction and modification. Plant protein adhesives have received 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, which reduces dependence on non-renewable resources such as petroleum. With the global emphasis on sustainable development and environmental protection, plant protein, as a renewable material, is particularly important in adhesives. 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 some technical challenges. First, insufficient bonding strength is a major problem in the current application of plant protein adhesives. In many cases, the bonding strength of plant protein adhesives is not as good as that of synthetic adhesives, which is mainly due to the limitations of the molecular structure of plant protein and its polymerization state. The bonding performance of plant protein may decrease under the influence of environmental factors such as moisture content, temperature, and pH value. In addition, plant protein adhesives require the participation of water during the bonding process, and excessive moisture will lead to the weakening of the bonding interface, thereby further reducing the bonding strength.

[0005] Bamboo artificial board is a product made of bamboo or wood, which is processed into boards by physical or chemical methods. It is widely used in the fields of construction, furniture, flooring, etc. In the production process of bamboo artificial board, the selection of adhesive is crucial. As a new type of environmentally friendly material, plant protein adhesive has significant advantages in bamboo artificial board. First, plant protein adhesive can fully combine with bamboo and wood fibers to form a good bonding effect. Secondly, plant protein adhesive has excellent biocompatibility, which helps to reduce the negative impact of bamboo artificial board on the environment. In addition, bamboo artificial board produced with plant protein adhesive can not only meet the standards of green and environmentally friendly products, but also enhance the market competitiveness of products.

[0006] However, in the prior art, bamboo artificial boards containing plant protein adhesives still have deficiencies in terms of mildew resistance, corrosion resistance, static bending strength and bending elastic modulus. Plant protein itself is susceptible to microbial invasion, especially in a humid environment, and its water resistance and mildew resistance are poor, which makes the board easy to mold and rot. In addition, due to the low degree of cross-linking of plant protein, the strength of the bonding interface is insufficient, which in turn affects the static bending strength and bending elastic modulus. These problems are mainly due to the limitations of the molecular structure of plant protein and its insufficient ability to combine 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 which has high bonding strength and mildew and corrosion resistance.

[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] 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, 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] The tetraformaldehyde reacts with the first initiator to open the ring to generate a terminal aldehyde compound, and there are active free radicals at the terminal tail position, which has high reactivity. The two ends of the terminal aldehyde compound connect cellulose and phthalic anhydride polyester polyol. Since cellulose and phthalic anhydride polyester polyol are long-chain macromolecules and have a large number of hydroxyl groups in their structures, the small molecule tetraformaldehyde free radicals can fully react with the hydroxyl groups on cellulose and phthalic anhydride polyester polyol to form a prepolymer. The 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 the tetraformaldehyde, cellulose and phthalic anhydride polyester polyol enables the formation of a double cross-linked network morphology in the subsequent curing reaction, which significantly enhances 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, wherein the introduction of the hydroxyl compound into the plant protein greatly increases the number of hydroxyl groups on the molecular chain, and the plant protein is more exposed in space, making it easier to participate in subsequent reactions with hydroxyl groups. Under the synergistic action of combination A and component B, the adhesive of the present invention is a plant protein adhesive with high bonding 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 tetraformaldehyde after ring opening 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 hydroxy 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 unrolled and unfolded to present 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 isobutylene alcohol 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, mixes cellulose, phthalic anhydride polyester polyol, tetraacetaldehyde and a first initiator, and heats and refluxes to obtain a modified nanocellulose prepolymer A;

[0046] S2 mixes the plant protein, the hydroxy compound and the second initiator in water, and pretreats the protein component B by heating and refluxing;

[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 an 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 an 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 further provides a bamboo artificial board, including the adhesive as described in the first embodiment. Since the application adopts all the technical solutions of the above adhesive, it at least has all the beneficial effects brought by the technical solutions of the above 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 using the adhesive of the present invention can maintain the stability of board performance and improve mechanical and anticorrosive 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 apparent 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 words "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that may 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] In the examples and comparative examples, 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.

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

[0067] In the embodiments and comparative examples, the vegetable protein is camellia oleifera cake protein.

[0068] Example 1

[0069] An adhesive, 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 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, tetraacetaldehyde and a first initiator, and heats to 90° C. under nitrogen protection and reflux treatment, and maintains the temperature for reaction for 3 hours to obtain a modified nanocellulose prepolymer A;

[0082] S2 mixed the vegetable protein, isobutylene alcohol and the second initiator in water, heated to 80°C under reflux conditions, and reacted 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, which 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, which 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, the phthalic anhydride polyester polyol is replaced by furfuryl alcohol resin.

[0110] Performance Test:

[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] It can be seen from Table 1 that the difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain phthalic anhydride polyester polyol, resulting in that component A of Comparative Example 1 cannot react effectively, and there is no substantial reaction even when blended with component B, so the composed board cannot be formed.

[0116] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, nanocellulose is replaced by starch. Since starch has weak reactivity with other substances and the starch molecule is short, although -OH in starch can still undergo a certain grafting reaction with phthalic anhydride polyester polyol, the subsequent curing reactivity with component B is poor, and an interpenetrating network structure cannot be effectively formed, resulting in poor bonding performance of the adhesive of Comparative Example 2, resulting in the need for the density of the board to reach a higher level in order to achieve molding, and the corresponding mildew resistance and corrosion resistance are poor, and the static bending strength and bending elastic modulus are also poor.

[0117] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, nanocellulose is replaced by glycerol. After nanocellulose is replaced by glycerol, the reaction of component A is weak, and the curing reaction with component B is also weak, resulting in the inability to form an interpenetrating network structure, weak bonding performance, and the inability to effectively hot press the board, resulting in the inability to detect density and mechanical properties. The board has poor corrosion resistance and mildew resistance.

[0118] Comparative Example 4: Phthalic anhydride polyester polyol is replaced by polycaprolactone polyol. On the one hand, the polycaprolactone molecular structure 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 weaker 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, tetraacetaldehyde is replaced by polyoxymethylene or acetaldehyde, which results in no reaction between component A and only physical blending. There is no reaction when mixed with component B for thermal curing, resulting in no reaction during the hot pressing process of the board, no actual hot pressing, and the density and mechanical properties cannot be detected, and the corrosion resistance and mildew resistance are 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. In the hot pressing molding of the plate, there is no curing reaction and no interpenetrating network structure is formed, so the density and mechanical properties cannot be tested.

[0121] 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. Furfuryl alcohol resin needs to be cured under acidic catalyst conditions, and Comparative Example 8 does not have such curing conditions, and the adhesive cannot be synthesized.

[0122] 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 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; Hydroxyl compounds; A second initiator; water.

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

4. An 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. An 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 protein, soybean cake protein and litsea cubeba cake protein.

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

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, under a protective atmosphere, mixes cellulose, phthalic anhydride polyester polyol, tetraacetaldehyde and a first initiator, and heats and refluxes to obtain a modified nanocellulose prepolymer A; S2 mixes the plant protein, the hydroxy compound and the second initiator in water, and pretreats the protein component B by heating and refluxing; S3: mixing the modified nanocellulose prepolymer A and the pretreated protein component B to obtain the adhesive.

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

9. A bamboo artificial board, characterized in that: The bamboo artificial board comprises an adhesive as described in any one of claims 1 to 6.

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

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