Modified cake protein adhesive, its preparation method and thin shaving board

Abstract

The application discloses a modified cake protein adhesive, a preparation method thereof and a thin shaving board, and the preparation raw material of the modified cake protein adhesive comprises plant protein, acrylate, a phosphorus-containing compound, lithium bis-trifluoromethanesulfonimide, a bromide and 1-vinylimidazole. The application provides the modified cake protein adhesive, improves the bonding performance, water resistance and mildew resistance of the protein-based adhesive, and the service life of the modified cake protein adhesive is more than 15 days.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of board modifiers, and particularly relates to a modified cake meal protein adhesive and a preparation method thereof and a thin shaving board. BACKGROUND

[0002] Wood and bamboo materials, such as poplar plantations, have the advantages of high yield and fast growth, but they have defects such as low wood density, poor mechanical strength, low surface hardness, low wear resistance, and poor corrosion resistance, which limit their use. Compared with natural forest wood, the properties and decoration of wood and bamboo materials are quite different. Therefore, it is necessary to chemically modify fast-growing wood. At present, the preparation of wood adhesives using chemical raw materials has become the mainstream of the industry, especially formaldehyde-based resins (such as urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), and phenol-formaldehyde resin (PF)), which have excellent bonding strength and water resistance and weather resistance, accounting for about 90% of wood adhesives. However, the 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 of increasingly stringent legal and regulatory requirements, the disadvantages of "formaldehyde-based" resin adhesives have attracted more and more attention and concern. 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 kind of green and environmentally friendly adhesive material mainly composed of natural proteins, 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 humidity and temperature changes, resulting in a decrease or loss of bonding strength. In addition, with the extension of storage time, protein molecules may be degraded, thereby affecting the performance of the adhesive. SUMMARY

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

[0004] According to a first aspect of the present application, a modified cake meal protein adhesive is provided, and the preparation raw materials of the modified cake meal protein adhesive include: plant 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 application, at least the following beneficial effects are achieved:

[0006] 1. The phosphorus-containing, bromine-containing, and other flame-retardant performance element-containing are introduced and connected by chemical covalent bond, so that the flame-retardant element is uniformly distributed, the flame-retardant performance of the modified cake protein adhesive is improved, the content of water-absorbing groups (such as amino, carboxyl, hydroxyl, and sulfhydryl) is reduced by introducing poly(ethylene glycol) methacrylate, and the water resistance of the adhesive is effectively improved, and the performance decline caused by water penetration is reduced.

[0007] 2. The structure of the glue solution is stabilized by introducing poly(ethylene glycol) methacrylate, and the storage period is effectively prolonged. This makes the adhesive not prone to deterioration, delamination and other problems during storage, and the service life is extended to more than 15 days, far exceeding the storage period of 6-12 hours of the traditional adhesive.

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

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

[0010] According to some embodiments of the present application, the bromide includes 3-bromo-1-propanol.

[0011] According to the second aspect of the present application, a preparation method of the modified cake protein adhesive is provided, including the following steps:

[0012] S1. After mixing and heating reaction of the bromide and 1-vinylimidazole, and mixing reaction of the lithium bis(trifluoromethanesulfonyl)imide solution, the impurities are removed to obtain a prepolymer A;

[0013] S2. After mixing and heating reaction of part of the pretreated plant protein, the prepolymer A, the poly(ethylene glycol) methacrylate, and the phosphorus-containing compound, a precursor C is obtained;

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

[0015] The precursor C is an ionic liquid monomer with double bonds and hydroxyl groups, and not only contains double bonds and hydroxyl groups, but also contains N-containing heterocyclic rings, which can rapidly react 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 application, the mass ratio of the bromide to the 1-vinylimidazole is 1:1-1.5.

[0017] According to some embodiments of the present application, the mass concentration of the lithium bis-trifluoromethanesulfonimide solution is 30-50 wt%.

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

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

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

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

[0022] The concept and the technical effects of the present application will be described in detail below in combination with embodiments, so as to fully understand the purposes, features and effects of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0023] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0024] Unless otherwise specified, "room temperature" in the present application means 25℃±5℃.

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

[0026] Unless otherwise specified, the specific conditions in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not marked with the manufacturer, which are all conventional products that can be purchased on the market.

[0027] The first aspect of the present application provides a modified meal protein adhesive, and raw materials for preparing the modified meal protein adhesive include: plant 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 application, the phosphorus-containing compound includes at least one of ammonium phosphate and phytic acid.

[0029] According to some embodiments of the present application, the bromide includes 3-bromo-1-propanol.

[0030] In combination with the second aspect, in some embodiments of the present application, a preparation method of the modified meal protein adhesive is provided, including the following steps:

[0031] S1. After mixing and heating reaction of the bromide and 1-vinylimidazole, and mixing reaction of lithium bis(trifluoromethanesulfonyl)imide solution, a prepolymer A is obtained after impurity removal;

[0032] S2. After mixing and heating reaction of part of the pretreated plant protein, the prepolymer A, the poly(ethylene glycol) methacrylate, and the phosphorus-containing compound, a precursor C is obtained;

[0033] S3. After mixing of the precursor C and the remaining pretreated plant protein, a modified meal protein-based adhesive is obtained.

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

[0035] In combination with the second aspect, in some embodiments of the present application, 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 application, 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 application, the plant protein pretreatment method includes mixing reaction of urea, sodium hydroxide, and plant protein.

[0038] In combination with the second aspect, in some embodiments of the present application, 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 application, the raw materials for preparing the artificial board include the modified meal protein adhesive.

[0040] Example 1

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

[0042] S1. 3-bromo-1-propanol and 1-vinylimidazole were mixed in a mass ratio of 1:1, and rapid stirring was continuously performed at 60°C for 1h. After the reaction was completed, rotary evaporation was performed, vacuum drying was performed at room temperature, and then the mixture was blended with lithium bis(trifluoromethanesulfonyl)imide aqueous solution (40wt%) in a mass ratio of 0.7:1. The mixture was heated to 80°C under the protection of nitrogen and reflux, and rapid stirring (3000rpm) was continuously performed for 3h. After the reaction was completed, cooling and standing were performed, the oil phase component was collected, and freeze-drying was performed to obtain a prepolymer A.

[0043] Protein component B was obtained by pretreating oil cake protein with urea. Urea, oil cake protein and water were mixed in a mass ratio of 0.02:0.2:0.78, and heating reaction was performed at 50°C for 3h.

[0044] S2. According to the mass percentage, 20% of the prepolymer A, 5% of the poly(ethylene glycol) methacrylate and 8% of the phytic acid were added to the protein component B for blending, and the balance was water. After uniform stirring, a mixed solution was obtained. 0.1wt% of an initiator (azo diisobutyl amide hydrochloride (AIBA)) was added to the mixed solution, and reaction was performed at 50°C for 20min. Then, rapid cooling was performed to room temperature to obtain a precursor C.

[0045] S3. The precursor C and the remaining protein component B were blended in a ratio of 1:0.2, and uniform stirring was performed to obtain a modified cake protein-based adhesive.

[0046] Example 2

[0047] The embodiment discloses a modified cake 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 other steps are the same as in example 1.

[0048] Example 3

[0049] The embodiment discloses a modified cake protein adhesive and a preparation method thereof. In S1, lithium bis(trifluoromethanesulfonyl)imide aqueous solution is blended in a ratio of 0.3:1, and the other steps are the same as in example 1.

[0050] Example 4

[0051] The embodiment discloses a modified cake protein adhesive and a preparation method thereof. In S2, the prepolymer A is 10%, and the other steps are the same as in example 1.

[0052] Example 5

[0053] The embodiment discloses a modified cake 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 other steps are the same as in example 1.

[0054] Example 6

[0055] This example discloses a modified cake protein adhesive and its preparation method, S2 uses camellia cake instead of tung oil cake, and the rest is the same as example 1.

[0056] Comparative Example 1

[0057] This comparative example discloses a preparation method of a water-resistant plant protein adhesive, the difference between this comparative example and example 1 is that propanol is used instead of 3-bromo-1-propanol, and the rest of the conditions are the same.

[0058] Comparative Example 2

[0059] This comparative example discloses a preparation method of a water-resistant plant protein adhesive, the difference between this comparative example and example 1 is that 3-chloro-1-propanol is used instead of 3-bromo-1-propanol, and the rest of the conditions are the same.

[0060] Comparative Example 3

[0061] This comparative example discloses a preparation method of a modified cake protein adhesive, the difference between this comparative example and example 1 is that phosphoric acid is used instead of phytic acid in example 1, and the rest of the conditions are the same.

[0062] Comparative Example 4

[0063] This comparative example discloses a preparation method of 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 rest of the conditions are the same.

[0064] Comparative Example 5

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

[0066] Test Example 1

[0067] This test example tests the performance of the bamboo-wood thin-flake board obtained by the example and comparative example, and the test results are shown in Table 1. Lightweight bamboo engineering material. Lightweight bamboo engineering material refers to reconstituted bamboo board with a density of less than 1.0 g / cm3. The density of traditional board is greater than 1.0 g / cm3, and the highest can reach 1.2 g / cm3. The density is too high, which seriously affects the convenience of transportation, installation and use of the board. In this paper, the density of the board is significantly reduced under the premise of maintaining the stability of the performance of the board (meeting the standard requirements, mechanics, corrosion and mildew resistance).

[0068] Table 1 Adhesive performance test

[0069]

[0070]

[0071] In the comparative example 1, 3-bromo-1-propanol is replaced by propanol. Although both have alcohol hydroxyl groups in the structure, 3-bromo-1-propanol has a more complex structure. In the S1 step, propanol cannot completely participate in the reaction with 1-vinylimidazole, so the prepolymer A in the S1 step cannot be obtained, and the subsequent reaction cannot occur. The components are simply blended, and after 15 days of storage test, the components gradually settle and precipitate due to immiscibility. The resulting product adhesive in the subsequent process cannot be fully cured during hot pressing, and cannot react with the protein component to form a crosslinked network structure. Therefore, the adhesive in the comparative example 1 cannot be used to form a board, and the mechanical properties cannot be detected, and the limiting oxygen index cannot be tested.

[0072] In the comparative example 2, 3-bromo-1-propanol is replaced by 3-chloro-1-propanol. Although the structures of the two are similar, both contain alcohol hydroxyl groups, but the covalently bonded bromine element in 3-bromo-1-propanol has stronger electrophilic ability than chlorine. In the S1 step, the reactivity with 1-vinylimidazole is also strong, so the prepolymer A in the S1 step cannot be fully obtained, resulting in lower reactivity in the subsequent reaction. The components are mainly blended, and after 15 days of storage test, the components gradually settle, precipitate and stratify due to immiscibility. The resulting product adhesive in the subsequent process cannot be fully cured during hot pressing, and it is difficult to form a complete crosslinked network structure. Therefore, the adhesive in the comparative example 2 cannot be used to form a board with high density, because the hot pressing forming pressure is high, and the mechanical properties are poorer than those of example 1. Due to insufficient reaction of the components, the substances with flame-retardant and reinforcing effects such as phytic acid cannot be uniformly distributed in the board after hot pressing and curing, resulting in a lower limiting oxygen index value.

[0073] In the comparative example 3, phytic acid is replaced by phosphoric acid. The structures of the two are quite different. Phytic acid is a hexaphosphoric acid structure organic phosphoric acid with strong acidity and strong chelating ability. Phosphoric acid is a monophosphoric inorganic acid. The reactivity of the two in the S2 step is quite different. Phytic acid can bond with other components through covalent bonds, while phosphoric acid does not have the related reaction ability. Therefore, in the S2 step, the reactivity of phosphoric acid with the components is weak, and the components are mainly blended. After 15 days of storage test, the components gradually settle, precipitate and stratify due to immiscibility. The resulting product adhesive in the subsequent process cannot be fully cured during hot pressing, and cannot react with the protein component to form a crosslinked network structure. Therefore, the adhesive in the comparative example 3 cannot be used to form a board, and the 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, there are significant differences in chemical structure, resulting in significant differences in the reaction in S3 step. Poly(ethylene glycol) methacrylate is a long-chain macromolecule, and in addition to containing an acrylate structure, it also has an alcohol hydroxyl group, which can react with other components in S3 step. The reaction of methyl methacrylate mainly occurs between its own components, and the reactivity with other components is weak, making the S3 step reaction insufficient, and the components are mainly blended. After 15 days of storage test, each component gradually separates, precipitates and stratifies due to immiscibility. The resulting product adhesive in Comparative Example 4 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 used to make boards with high density. Because the hot pressing forming pressure is high, the mechanical properties are poorer than those of Example 1. Due to insufficient reaction of each component, the flame-retardant reinforcing effect of phytic acid and other substances cannot be uniformly distributed in the board after hot pressing and curing, resulting in a lower limiting oxygen index value.

[0075] In Comparative Example 5, an equal amount of water is used to replace lithium bis(trifluoromethanesulfonyl)imide aqueous solution. In the S1 step reaction, there is no lithium bis(trifluoromethanesulfonyl)imide as a response initiator and catalyst, so the prepolymer A in S1 step cannot be obtained, and the subsequent reaction cannot occur. Each component is simply blended, and after 15 days of storage test, each component gradually separates and precipitates due to immiscibility. The resulting product adhesive in Comparative Example 5 cannot be cured during hot pressing, and cannot react with the protein component to form a cross-linked network structure, so the adhesive in Comparative Example 5 cannot be used to make boards, and the mechanical properties cannot be tested, and the limiting oxygen index cannot be tested.

[0076] The above describes the embodiments of the present application in detail, but the present application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present application.

Claims

1. A modified meal protein adhesive, characterized by, The preparation raw material of the modified meal protein adhesive comprises plant protein, poly(ethylene glycol) methacrylate, phosphorus-containing compound, lithium bis-trifluoromethanesulfonimide, bromide and 1-vinylimidazole. The modified meal protein adhesive is prepared by the following steps: S1. After mixing and heating reaction, the bromide and 1-vinylimidazole are mixed and reacted with lithium bis-trifluoromethanesulfonimide solution, and then impurities are removed to obtain a prepolymer A; S2. After mixing and heating reaction, part of the pretreated plant protein, the prepolymer A, the acrylic ester and the phosphorus-containing compound are mixed to obtain a precursor C; S3. The precursor C and the remaining pretreated plant protein are mixed to obtain the modified meal protein-based adhesive; The phosphorus-containing compound is phytic acid. The bromide is 3-bromo-1-propanol.

2. The modified meal protein adhesive according to claim 1, wherein, The mass ratio of the bromide to the 1-vinylimidazole is 1:0.5-1.

5.

3. The modified meal protein adhesive according to claim 1, wherein The mass concentration of the lithium bis-trifluoromethanesulfonimide solution is 30-50 wt%.

4. The modified meal protein adhesive according to claim 1, wherein In step S1, the temperature of the mixing reaction is 80-90℃.

5. The modified meal protein adhesive according to claim 1, wherein The plant protein pretreatment method comprises mixing urea, sodium hydroxide and plant protein.

6. The modified meal protein adhesive of claim 1, wherein, In step S3, the mass ratio of the precursor C to the plant protein is 1:0.2-0.

5.

7. A thin chipboard, characterized in that The preparation raw material of the thin shaving board comprises the modified meal protein adhesive according to any one of claims 1-6. The preparation raw material of the thin shaving board comprises the modified meal protein adhesive according to any one of claims 1-6.

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