Modified cake meal protein adhesive, preparation method thereof and thin shaving board

Abstract

The invention discloses a modified cake protein adhesive, a preparation method of the modified cake protein adhesive and a thin shaving board. The modified cake protein adhesive is prepared from the following raw materials: vegetable protein, acrylate, a phosphorus-containing compound, lithium bis (trifluoromethanesulfonimide), a bromide and 1-vinyl imidazole. According to the modified cake protein adhesive provided by the invention, the bonding performance, the water resistance and the mildew-proof performance of a protein-based adhesive are improved, and the service life reaches 15 days or above.

Description

Technical Field

[0001] The invention belongs to a board modifier, and in particular relates to a modified cake protein adhesive and a preparation method thereof, and a thin particleboard. Background Art

[0002] Wood and bamboo materials, such as poplar plantations, have the advantages of high yield and fast growth, but their low wood density, poor mechanical strength, low surface hardness, low wear resistance and poor corrosion resistance limit their use. Compared with natural forest wood, their material properties and decorative properties are far different. Therefore, it is extremely necessary to chemically modify fast-growing forest wood. At present, the use of chemical raw materials to prepare wood adhesives has become the mainstream of the industry, especially formaldehyde-based resins (such as urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), phenolic resin (PF), etc.), which account for about 90% of the proportion in wood adhesives due to excellent bonding strength and water resistance and weather resistance. However, a fatal defect of "formaldehyde-based" resins is the harm of formaldehyde to the human body and the environment. With the continuous improvement of economic level and people's quality of life, especially under the background conditions of increasingly stringent laws and regulations, the disadvantages of "formaldehyde-based" resin adhesives have attracted more and more attention and concern from people, and the development of non-toxic, green and environmentally friendly new wood adhesives has far-reaching significance for the development of the industry. Protein-based adhesives, as a green and environmentally friendly adhesive material with natural protein as the main component, have attracted widespread attention in recent years due to their good biodegradability, low toxicity and excellent bonding performance. However, traditional protein-based adhesives still face some technical challenges in practical applications, especially in terms of bonding performance, water resistance, storage stability and functionality. For example, protein-based adhesives have poor hydrolytic stability and are easily affected by changes in humidity and temperature, resulting in reduced bonding strength or failure. In addition, as the storage time increases, protein molecules may degrade, which in turn affects the performance of the adhesive. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a modified cake protein adhesive, which improves the bonding performance, water resistance and mildew resistance of the protein-based adhesive.

[0004] According to a first aspect of the present invention, a modified meal protein adhesive is provided. The raw materials for preparing the modified meal protein adhesive include: vegetable protein, poly(ethylene glycol) methacrylate, phosphorus-containing compound, lithium bis(trifluoromethanesulfonyl imide), bromide and 1-vinylimidazole.

[0005] According to the embodiments of the first aspect of the present invention, there are at least the following beneficial effects:

[0006] 1. Flame retardant elements such as phosphorus and bromine are introduced and connected through chemical covalent bonds to make the flame retardant elements evenly distributed, thereby improving the flame retardant properties of the modified cake protein adhesive. By introducing poly (ethylene glycol) methacrylate, the content of water-absorbing groups (such as amino, carboxyl, hydroxyl, thiol, etc.) is reduced, effectively improving the water resistance of the adhesive and reducing the performance degradation caused by water penetration.

[0007] 2. By introducing poly(ethylene glycol) methacrylate, the structure of the adhesive is stabilized and the storage period is effectively extended. This makes the adhesive less likely to deteriorate and delaminate during storage, and the service life is extended to more than 15 days, far exceeding the traditional storage period of 6-12 hours.

[0008] 3. Through the reaction of poly(ethylene glycol) methacrylate with the active groups on the protein components, the active groups on the protein macromolecules are condensed to form a stable covalent bond, which not only effectively reduces the content of water-absorbing groups (amino, carboxyl, hydroxyl, thiol, etc.) in the adhesive product, but also forms a macromolecular three-dimensional network structure through the reaction with the active groups, effectively enhancing the mechanical properties of the cured adhesive

[0009] According to some embodiments of the invention, the phosphorus-containing compound comprises at least one of ammonium phosphate and phytic acid.

[0010] According to some embodiments of the present invention, the brominated compound includes: 3-bromo-1-propanol.

[0011] According to a second aspect of the present invention, a method for preparing the modified meal protein adhesive is provided, comprising the following steps:

[0012] S1. mixing the bromide and 1-vinyl imidazole, heating them, and then mixing them with a lithium bis(trifluoromethanesulfonyl)imide solution, and removing impurities to obtain a prepolymer A;

[0013] S2. mixing the partially pretreated plant protein, the prepolymer A, the poly(ethylene glycol) methacrylate, and the phosphorus-containing compound, and heating the mixture to obtain a precursor C;

[0014] S3. Mixing the precursor C and the remaining pretreated plant protein to obtain a modified cake protein-based adhesive.

[0015] Precursor C is an ionic liquid monomer having double bonds and hydroxyl groups. It not only contains double bonds and hydroxyl groups, but also contains a heterocyclic ring of N, which can react quickly with subsequent protein components and prepolymers to form covalent bonds and form a stable adhesive emulsion system.

[0016] According to some embodiments of the present invention, the mass ratio of the bromide to the 1-vinylimidazole is 1:1 to 1.5.

[0017] According to some embodiments of the present invention, the mass concentration of the lithium bis(trifluoromethanesulfonyl)imide solution is 30-50 wt %.

[0018] According to some embodiments of the present invention, in step S1, the temperature of the mixing reaction is 80-90°C.

[0019] According to some embodiments of the present invention, the method for pretreating plant protein comprises: mixing urea, sodium hydroxide and plant protein for reaction.

[0020] According to some embodiments of the present invention, in step S3, the mass ratio of the precursor C to the plant protein is 1:0.2-0.5.

[0021] According to a third aspect of the present invention, a wood-based panel is provided, wherein the raw materials for preparing the wood-based panel include the modified cake protein adhesive. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0023] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0024] Unless otherwise specified, "room temperature" in the present invention means 25°C±5°C.

[0025] Unless otherwise specified, "about" in the present invention means that the allowable error is within ±2%.

[0026] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0027] The first aspect of the present invention provides a modified meal protein adhesive, wherein the raw materials for preparing the modified meal protein adhesive include: vegetable protein, poly(ethylene glycol) methacrylate, phosphorus-containing compound, lithium bis(trifluoromethanesulfonyl imide), bromide and 1-vinylimidazole.

[0028] In combination with the first aspect, in some embodiments of the present invention, the phosphorus-containing compound includes at least one of ammonium phosphate and phytic acid.

[0029] According to some embodiments of the present invention, the brominated compound includes: 3-bromo-1-propanol.

[0030] In combination with the second aspect, in some embodiments of the present invention, a method for preparing the modified meal protein adhesive is proposed, comprising the following steps:

[0031] S1. mixing the bromide and 1-vinyl imidazole, heating them, and then mixing them with a lithium bis(trifluoromethanesulfonyl)imide solution, and removing impurities to obtain a prepolymer A;

[0032] S2. mixing the partially pretreated plant protein, the prepolymer A, the poly(ethylene glycol) methacrylate, and the phosphorus-containing compound, and heating the mixture to obtain a precursor C;

[0033] S3. Mixing the precursor C and the remaining pretreated plant protein to obtain a modified cake protein-based adhesive.

[0034] In combination with the second aspect, in some embodiments of the present invention, the mass ratio of the bromide to the 1-vinylimidazole is 1:1 to 1.5.

[0035] In combination with the second aspect, in some embodiments of the present invention, the mass concentration of the lithium bis(trifluoromethanesulfonyl)imide solution is 30-50 wt %.

[0036] In combination with the second aspect, in some embodiments of the present invention, in step S1, the temperature of the mixing reaction is 80-90°C.

[0037] In combination with the second aspect, in some embodiments of the present invention, the method for pretreating the plant protein includes: mixing urea, sodium hydroxide and the plant protein for reaction.

[0038] In combination with the second aspect, in some embodiments of the present invention, in step S3, the mass ratio of the precursor C to the plant protein is 1:0.2-0.5.

[0039] In combination with the third aspect, in some embodiments of the present invention, the raw materials for preparing the artificial board include the modified cake protein adhesive.

[0040] Example 1

[0041] This embodiment discloses a modified meal protein adhesive and a preparation method thereof, and the specific steps are as follows:

[0042] S1. 3-bromo-1-propanol and 1-vinyl imidazole were first mixed in a mass ratio of 1:1, and stirred rapidly at 60°C for 1 hour. After the reaction was completed, the mixture was rotary evaporated, dried in vacuum at room temperature, and then mixed with an aqueous solution of lithium bis(trifluoromethanesulfonyl)imide (40wt%) in a mass ratio of 0.7:1. The mixture was heated to 80°C under nitrogen protection and reflux conditions, and stirred rapidly (3000rpm) for 3 hours. After the reaction was completed, the mixture was cooled and allowed to stand, the oil phase component was collected, and freeze-dried to obtain prepolymer A;

[0043] The protein component B was obtained by pretreating the tung oil cake protein with urea, and urea, tung oil cake protein and water were mixed in a mass ratio of 0.02:0.2:0.78 and heated at 50°C for 3 hours;

[0044] S2. According to the mass percentage, 20% of prepolymer A, 5% of poly(ethylene glycol) methacrylate, and 8% of phytic acid were added to the protein component B and blended, with the balance being water. After stirring evenly, a mixed solution was obtained, and 0.1wt% of the initiator (azobisisobutylamidine hydrochloride (AIBA)) was added to the mixed solution. After reacting at 50°C for 20min, the mixture was rapidly cooled to room temperature to obtain a precursor C.

[0045] S3. Blend the precursor C and the remaining protein component B in a ratio of 1:0.2 and stir until uniform to obtain a modified cake protein-based adhesive.

[0046] Example 2

[0047] This embodiment discloses a modified meal protein adhesive and a preparation method thereof. In S1, 3-bromo-1-propanol and 1-vinylimidazole are mixed in a mass ratio of 1:0.5, and the rest is the same as in Embodiment 1.

[0048] Example 3

[0049] This embodiment discloses a modified meal protein adhesive and a preparation method thereof. The aqueous solution of lithium bis(trifluoromethanesulfonyl imide) in S1 is blended at a ratio of 0.3:1, and the rest is the same as in Embodiment 1.

[0050] Example 4

[0051] This embodiment discloses a modified cake protein adhesive and a preparation method thereof. In S2, the prepolymer A accounts for 10%, and the rest is the same as in Example 1.

[0052] Example 5

[0053] This embodiment discloses a modified meal protein adhesive and a preparation method thereof. In S3, the precursor C and the remaining protein component B are blended in a ratio of 1:0.4, and the rest is the same as in Embodiment 1.

[0054] Example 6

[0055] This embodiment discloses a modified cake protein adhesive and a preparation method thereof. In S2, camellia oil cake is used instead of tung oil cake, and the rest is the same as in Embodiment 1.

[0056] Comparative Example 1

[0057] This comparative example discloses a method for preparing a water-resistant plant protein adhesive. The difference between this comparative example and Example 1 is that 3-bromo-1-propanol is replaced by propanol, and the other conditions are the same.

[0058] Comparative Example 2

[0059] This comparative example discloses a method for preparing a water-resistant plant protein adhesive. The difference between this comparative example and Example 1 is that 3-chloro-1-propanol is used to replace 3-bromo-1-propanol, and the other conditions are the same.

[0060] Comparative Example 3

[0061] This comparative example discloses a method for preparing a modified cake protein adhesive. The difference between this comparative example and Example 1 is that phosphoric acid is used to replace the phytic acid in Example 1, and the other conditions are the same.

[0062] Comparative Example 4

[0063] This comparative example discloses a method for preparing a water-resistant plant protein adhesive. The difference between this comparative example and Example 1 is that methyl methacrylate is used instead of poly(ethylene glycol) methacrylate, and the other conditions are the same.

[0064] Comparative Example 5

[0065] This comparative example discloses a method for preparing a modified cake protein adhesive. The difference between this comparative example and Example 1 is that an equal amount of water is used to replace the lithium bis(trifluoromethanesulfonyl)imide aqueous solution in S1, and the other conditions are the same.

[0066] Test Example 1

[0067] This test example tests the performance of the bamboo-wood thin particleboard obtained in the comparative example of the embodiment, and the test results are shown in Table 1. Preparation of lightweight bamboo engineering materials. Lightweight bamboo engineering materials refer to reconstituted bamboo boards with a density lower than 1.0g / cm3. The density of traditional boards is greater than 1.0g / cm3, and can reach up to 1.2g / cm3. Too high a density seriously affects the convenience of transportation, installation and use of the boards. This article maintains the stability of the board performance (in compliance with standard requirements, mechanics, anti-corrosion and anti-mildew) under the premise of significantly reducing the density of the board.

[0068] Table 1 Adhesive performance test

[0069]

[0070]

[0071] In Comparative Example 1, propanol is used to replace 3-bromo-1-propanol. Although both of them have alcoholic hydroxyl groups in the structure, the structure of 3-bromo-1-propanol is more complicated. In the reaction of step S1, propanol cannot fully participate in the reaction with 1-vinylimidazole, so the prepolymer A in step S1 cannot be obtained, resulting in the subsequent reaction cannot occur. Each component is simply blended. After 15 days of storage test, each component gradually precipitates due to immiscibility. The subsequent product adhesive cannot be fully cured during the hot pressing process, and cannot react with the protein component to form a cross-linked network structure. Therefore, the adhesive in Comparative Example 1 cannot be formed into a sheet, the mechanical properties cannot be detected, and the limiting oxygen index cannot be tested.

[0072] 3-chloro-1-propanol is used to replace 3-bromo-1-propanol in Comparative Example 2. Although the two structures are similar, both contain alcoholic hydroxyl groups, the bromine element covalently connected in 3-bromo-1-propanol, electrophilic ability is stronger than chlorine element, in the reaction of S1 step, the reactivity with 1-vinyl imidazole is also strong, therefore the prepolymer A in S1 step cannot be fully obtained, resulting in a lower subsequent reaction activity, each component is mainly blended, and after 15 days of storage test, each component is gradually precipitated, precipitated and layered due to immiscible. The subsequent product adhesive obtained cannot be fully cured during hot pressing, and it is difficult to form a complete cross-linked network structure, so the adhesive in Comparative Example 2 cannot be that the sheet density is higher, because it is required that the hot pressing molding pressure is higher, and the mechanical property is poorer than Example 1. Because each component reaction is insufficient, after hot pressing curing, materials such as phytic acid with flame retardant enhancement effect cannot be evenly distributed inside the sheet, resulting in a lower limiting oxygen index value.

[0073] Phytic acid is replaced by phosphoric acid in Comparative Example 3, and the two have large structural differences. Phytic acid is an organic phosphoric acid with a hexaphosphate structure, which is highly acidic and has a strong chelating ability. Phosphoric acid is a monophosphorus inorganic acid. The reactivity of the two in step S2 is quite different. Phytic acid can bond with other components through covalent bonds, and phosphoric acid does not have relevant reactivity. Therefore, phosphoric acid has weak reactivity with each component in step S2, mainly for blending. After 15 days of storage test, each component gradually settles, precipitates and delaminates due to immiscibility. The subsequent product adhesive obtained cannot be fully cured during the hot pressing process, and cannot react with the protein component to form a cross-linked network structure. Therefore, the adhesive in Comparative Example 3 cannot be sheet forming, mechanical properties cannot be detected, and the limiting oxygen index cannot be tested.

[0074] In comparative example 4, methyl methacrylate is used to replace poly (ethylene glycol) methacrylate, although both are acrylate substances, but the chemical structure has significant differences, causing it to react in step S3 with significant differences. Poly (ethylene glycol) methacrylate is a long-chain macromolecule, and in addition to containing acrylate structure on the chemical group, there is also alcoholic hydroxyl group, and multiple reactions can occur with other components in step S3, and the hair of methyl methacrylate mainly occurs between its own components, and the reactivity with other components is weak, so that the reaction of step S3 is insufficient, and each component is mainly blended, and after 15 days of storage test, each component is gradually precipitated, precipitated and layered due to immiscible. The subsequent product adhesive obtained cannot be fully cured during hot pressing, and it is difficult to form a complete cross-linked network structure, so the adhesive in comparative example 4 cannot be that the density of the sheet is higher, because it is necessary to have a higher pressure of hot pressing molding, and the mechanical property is poorer than Example 1. Because each component reaction is insufficient, after hot pressing curing, materials such as phytic acid with flame retardant enhancement effect cannot be evenly distributed inside the sheet, causing the limiting oxygen index value to be also lower.

[0075] In Comparative Example 5, an equal amount of water was used to replace the aqueous solution of lithium bis(trifluoromethanesulfonyl)imide. In the reaction of step S1, there was no lithium bis(trifluoromethanesulfonyl)imide as a reaction initiator and catalyst, so the prepolymer A in step S1 could not be obtained, resulting in the inability to undergo subsequent reactions. The components were simply blended, and after 15 days of storage testing, the components gradually precipitated due to immiscibility. The subsequent product adhesive could not be cured during the hot pressing process, and could not react with the protein component to form a cross-linked network structure. Therefore, the adhesive in Comparative Example 5 could not be formed into a sheet, the mechanical properties could not be tested, and the limiting oxygen index could not be tested.

[0076] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A modified meal protein adhesive, characterized in that: The raw materials for preparing the modified cake protein adhesive include: vegetable protein, poly(ethylene glycol) methacrylate, phosphorus-containing compound, lithium bis(trifluoromethanesulfonyl imide), bromide and 1-vinyl imidazole.

2. The modified meal protein adhesive according to claim 1, characterized in that: The phosphorus-containing compound includes at least one of ammonium phosphate and phytic acid.

3. The modified meal protein adhesive according to claim 1, characterized in that: The brominated compounds include: 3-bromo-1-propanol.

4. A method for preparing the modified meal protein adhesive according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. mixing the bromide and 1-vinyl imidazole, heating them, and then mixing them with a lithium bis(trifluoromethanesulfonyl)imide solution, and removing impurities to obtain a prepolymer A; S2. mixing the partially pretreated plant protein and the prepolymer A, the acrylate, and the phosphorus-containing compound, and heating the mixture to obtain a precursor C; S3. Mixing the precursor C and the remaining pretreated plant protein to obtain a modified cake protein-based adhesive.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the bromide to the 1-vinylimidazole is 1:0.5-1.

5.

6. The preparation method according to claim 4, characterized in that: The mass concentration of the lithium bis(trifluoromethanesulfonyl)imide solution is 30-50wt%.

7. The preparation method according to claim 4, characterized in that: In step S1, the temperature of the mixing reaction is 80-90°C.

8. The preparation method according to claim 4, characterized in that: The plant protein pretreatment method comprises: mixing urea, sodium hydroxide and plant protein for reaction.

9. The preparation method according to claim 4, characterized in that: In step S3, the mass ratio of the precursor C to the plant protein is 1:0.2-0.

5.

10. A thin particle board, characterized in that: The raw material for preparing the thin particleboard includes the modified cake protein adhesive described in any one of claims 1 to 3.

Images