Flame-retardant biomass soybean protein tannin foamed plastic as well as preparation method and application thereof

Abstract

The invention relates to the technical field of foam material preparation, and particularly discloses flame-retardant biomass soybean protein tannin foam plastic and a preparation method and application thereof.The preparation method specifically comprises the steps that agriculture and forestry processing residue soybean cake meal protein, tannin and water are mixed to be uniform, then sodium hydroxide and a sodium phytate solution are added, uniform low-speed mixing is continued, and the flame-retardant biomass soybean protein tannin foam plastic is obtained; and adding a certain amount of Tween-80 into the mixed system, stirring at room temperature to foam, and freeze-drying to obtain the biomass soybean protein-based foamed plastic. The porous foamed plastic obtained by the method has the advantages of low raw material cost and wide raw material source, belongs to flame-retardant foamed plastic, and has a wide application prospect in the field of building decoration.

Description

Technical Field

[0001] The invention belongs to the technical field of foaming materials, and in particular relates to a flame-retardant biomass soybean protein tannin foam plastic and a preparation method and application thereof. Background Art

[0002] Foam plastics are widely used in the field of building decoration, such as polystyrene (EPS) foam, polyurethane (PU) foam, phenolic foam (PF), etc. However, the main raw materials of the above materials are derived from fossil-based raw materials or have flammable defects. Therefore, based on the research and development background of sustainable development of materials, it is of great significance to develop biomass foam plastics based on cheap agricultural and forestry biomass waste resources.

[0003] Existing literature (Properties of gluten foams containing different additives [J]. Industrial Crops and Products, 2020, 152, 112511) uses wheat gluten protein to prepare a porous foam plastic by thermal foaming. The report uses carbon dioxide decomposed by calcium carbonate under heat as a foaming agent; Patent (ZL 201610375163.7) uses wheat alcohol-soluble protein and chitosan as raw materials, and uses genipin as a cross-linking agent to prepare a porous material prepared by cross-linking protein, which is mainly used in biocatalysis, chemical industry, medicine, food and other fields; Patent (ZL 201710954400.X) uses saponin plant protein and tea saponin plant protein as the basis, a series of additives, and a protein foam foaming agent prepared by polymerization and cross-linking under heat, which is used as an additive for concrete to prepare foamed concrete building materials; Publication No. (CN 113512230A) Based on wheat gluten protein, a wheat gluten biomass foam material was prepared by freeze drying by adding cross-linking agents such as glutaraldehyde or glyoxal. However, it can be found that there is no relevant report on biomass foam plastics based on soy protein as raw material and biomass environmentally friendly cross-linking agent, and the above-mentioned foam materials based on plant protein all need to introduce non-environmentally friendly cross-linking agents into the system to ensure the molding of the foam material.

[0004] In addition, types of foam materials based on biomass tannins have been reported, such as directly utilizing bark liquefaction products for foaming (ZL 201810795287.X), foaming tannin resin by rapid mechanical whipping (ZL 202010184786.2), and foaming tannin resin by steam drive (ZL202211084183.0). However, they are all based on tannin-furfuryl alcohol as the basic system, which undergoes polymerization and cross-linking under the action of acid catalysis. The negative impact of this on the foam material is that the acid is too strong and easy to precipitate, which can easily cause environmental pollution and other problems.

[0005] Based on the defects shown in the development of the above-mentioned foam materials: plant protein-based foam materials require the introduction of environmentally unfriendly or even toxic cross-linking agents, and biomass tannin-based foam plastics are all prepared under strong acidic conditions, which poses a risk of acid precipitation and environmental pollution, and their subsequent application areas are greatly hindered. Summary of the invention

[0006] The purpose of the present invention is to provide a flame retardant biomass soybean protein tannin foam plastic and its preparation method and application to address the above-mentioned deficiencies of the prior art, and to prepare an environmentally friendly, low-cost biomass foam plastic with excellent mechanical properties and industrialization prospects under alkaline environmental conditions.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] The first object of the present invention is to provide a method for preparing a flame retardant biomass soybean protein tannin foam plastic, comprising the following steps:

[0009] S1, prepare 10%-30% sodium hydroxide and 10%-30% sodium phytate solution, set aside;

[0010] S2, mixing soybean protein, tannin source and distilled water uniformly to obtain a first mixed solution; the tannin source is any one of bayberry tannin, rubber bowl tannin or mimosa tannin;

[0011] S3, adding the sodium hydroxide solution and the sodium phytate solution described in step S1 into the first mixed solution, and mixing them evenly with mechanical stirring to obtain a second mixed solution;

[0012] S4, adding Tween-80 to the second mixed solution, and whipping it at high speed to make it foam, to obtain liquid foam;

[0013] S5. Pour the liquid foam obtained in step S4 into a mold and freeze-dry it for 24-48 hours to obtain the biomass soybean protein tannin foam plastic.

[0014] Furthermore, the soy protein is defatted protein or isolated protein, and the protein content of the soy protein is not less than 45%.

[0015] Furthermore, the tannin content in the tannin source is not less than 66%.

[0016] Furthermore, the mass ratio of the soy protein to the tannin source is 1:(0.07-0.47).

[0017] Furthermore, the mass ratio of the soy protein to sodium phytate is 1:(0.07-1.5).

[0018] Furthermore, the Tween-80 is added in an amount of 2-12% of the soybean protein.

[0019] Furthermore, in step S3, the rotation speed of the mechanical stirring is 900-1400 r / min.

[0020] The second object of the present invention is to provide a biomass soybean protein tannin foam plastic prepared by the above-mentioned preparation method.

[0021] The third object of the present invention is to provide a flame retardant product, comprising the biomass soybean protein tannin foam plastic.

[0022] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0023] (1) The present invention proposes a flame-retardant biomass soybean protein tannin foam plastic and a preparation method thereof. The foam plastic is based on soybean protein, with biomass tannin and sodium phytate as soybean protein crosslinking agents, forming covalent crosslinks through nucleophilic addition reactions, and forming a stable structure with the assistance of ionic bonds and hydrogen bonds. Compared with other types of existing plant protein foam plastics or materials, the proportion of raw biomass materials added in the scheme of the present invention is high; compared with the existing foam materials based on tannin furfuryl alcohol, the preparation process of the invention product does not require the use of acid catalysts, and thus there is no acid precipitation causing environmental pollution problems, and its alkaline properties provide basic conditions for the expansion of its application fields (water pollution control, etc.); the sodium phytate added to the invention product plays a dual role in the system, one is that its unique groups form stable crosslinks with the active groups of soybean protein, and the other is that the phosphorus element it contains provides the foam material with extremely excellent flame retardant properties without the need to add additional flame retardants; compared with the existing plant protein-related foam products used in the field of building materials, the invention product has the advantages of a high proportion of biomass raw materials, simple preparation, light weight and flame retardancy, and can be directly used as a building wall filling material. Combining the advantages of the invention product, it can be concluded that it has broad application prospects in the field of architectural decoration;

[0024] (2) The main raw materials used in the biomass soybean protein tannin foam plastic technical solution provided by the present invention are all derived from the residual products of agricultural and forestry processing. Compared with other types of plant proteins, soybean protein has a richer source and a lower price. In comparison, the present invention proposes to use biomass tannin and sodium phytate as soybean protein cross-linking agents, form covalent cross-links through nucleophilic addition reactions, and assist in forming a stable structure by combining ionic bonds and hydrogen bonds, and the raw material biomass accounts for a high proportion in the solution of the present invention. In addition, the addition of sodium phytate ingredients brings additional flame retardant properties to the foam material, expanding its application field. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a photo of the biomass soy protein tannin foam plastic provided by the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present invention clearer, the specific embodiments of the present invention are further described in detail below in conjunction with specific examples and drawings. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially.

[0027] Information on tannins used in the present invention: tannins from cassia tartrate and bayberry tannin, from Guangxi Lingshui Forest Chemical Co., Ltd. (formerly Guangxi Wuming Tannin Factory); mimosa tannin, from Silva Chimica (St. Michele Mondovi, Italy). Among them, bayberry tannin is powdery, light brown, and has a tannin content of 68% to 70%; tannins from cassia tartrate are brown-yellow to brown-brown, powdery or blocky, and have a tannin content of 66% to 68%; the effective tannin content in mimosa tannin is not less than 82%.

[0028] Example 1

[0029] 26g of soy protein isolate and 4g of bayberry tannin extract were added to a plastic beaker, followed by 170g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0030] Example 2

[0031] 26g of soy protein isolate and 8g of bayberry tannin extract were added to a plastic beaker, followed by 166g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0032] Example 3

[0033] 26g of soy protein isolate and 12g of bayberry tannin extract were added to a plastic beaker, followed by 162g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0034] Example 4

[0035] 26g of soy protein isolate and 12g of bayberry tannin extract were added to a plastic beaker, followed by 162g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 30g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0036] Example 5

[0037] 26g of soy protein isolate and 12g of bayberry tannin extract were added to a plastic beaker, followed by 162g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 40g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0038] Example 6

[0039] 26g of soy protein isolate and 12g of mimosa tannin were added to a plastic beaker, followed by 162g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0040] Example 7

[0041] 26g of soy protein isolate and 12g of rubber tannin (a hydrolyzed tannin) were added to a plastic beaker, followed by 162g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0042] Comparative Example 1

[0043] 26g of soy protein isolate and 12g of bayberry tannin extract were added to a plastic beaker, followed by 162g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0044] Comparative Example 2

[0045] 26g of soy protein isolate and 8g of bayberry tannin extract were added to a plastic beaker, followed by 162g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) solution was added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0046] Comparative Example 3

[0047] 26g of soy protein isolate and 4g of bayberry tannin extract were added to a plastic beaker, followed by 170g of water, and the mixture was stirred evenly; 12g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5min to foam. The liquid foam was poured into a mold and placed in an 80℃ electric blast drying oven for 12h, thereby preparing a biomass soy protein tannin foam plastic.

[0048] Comparative Example 4

[0049] 26g of soy protein isolate and 4g of bayberry tannin extract were added to a plastic beaker, followed by 170g of water, and the mixture was stirred evenly; 20g of sodium phytate (20wt%) solution was added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0050] Comparative Example 5

[0051] 26g of soy protein isolate and 4g of bayberry tannin extract were added to a plastic beaker, followed by 170g of water, and the mixture was stirred evenly; 26g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and the mixture was further stirred evenly; finally, 3g of Tween-80 was added to the mixture, and the mixture was whipped at high speed for 5 minutes to foam. The liquid foam was poured into a mold, and freeze-dried to prepare a biomass soy protein tannin foam plastic.

[0052] Comparative Example 6

[0053] 26g of soy protein isolate and 8g of bayberry tannin extract were added to a plastic beaker, followed by 166g of water, and stirred evenly; 12g of sodium hydroxide (20wt%) and 20g of sodium phytate (20wt%) solution were added to the mixture, and stirred evenly; 3g of Tween-80 was added to the mixture, and after stirring evenly, the mixed solution was poured into a mold and placed in an ultrasonic device. Then, freeze-dried to obtain the product.

[0054] The flame retardant biomass soybean protein tannin foam plastics prepared in Examples 1 to 7 and Comparative Examples 1 to 6 were subjected to performance tests, and the results are shown in Table 1.

[0055] Table 1. Performance test table

[0056]

[0057] From Examples 1-7 in the table, it can be concluded that the inventive method can obtain soybean protein tannin foam plastics, and can be applied to different types of tannin source materials. However, the difference is that Comparative Example 1 did not obtain a stable foam material, and its product had a very high slag rate; Comparative Example 2 can obtain foam plastics, but compared with the embodiment, its product has a poor flame retardant effect, which verifies the dual role of sodium phytate in foam molding and flame retardancy improvement; Comparative Example 3 verifies that a stable foam plastic product cannot be obtained under the action of thermal crosslinking; Comparative Example 4 can obtain molding, but its foam plastic is very easy to slag, which verifies the importance of alkaline environment in the preparation process of the product of the present invention; Comparative Example 5 shows that an overly strong alkaline environment is not conducive to the molding of lightweight foam plastics; Comparative Example 5 shows that mechanical whipping is crucial for the molding of lightweight foam plastics of the present invention.

[0059] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a flame retardant biomass soybean protein tannin foam plastic, characterized in that: The following steps are involved: S1, prepare 10%-30% sodium hydroxide and 10%-30% sodium phytate solution, set aside; S2, mixing soybean protein, tannin source and distilled water uniformly to obtain a first mixed solution; the tannin source is any one of bayberry tannin, rubber bowl tannin or mimosa tannin; S3, adding the sodium hydroxide solution and the sodium phytate solution described in step S1 into the first mixed solution, and mixing them evenly with mechanical stirring to obtain a second mixed solution; S4, adding Tween-80 to the second mixed solution, and whipping it at high speed to make it foam, to obtain liquid foam; S5. Pour the liquid foam obtained in step S4 into a mold and freeze-dry it for 24-48 hours to obtain the biomass soybean protein tannin foam plastic.

2. The preparation method according to claim 1, characterized in that The soy protein is defatted protein or isolated protein, and the protein content of the soy protein is not less than 45%.

3. The preparation method according to claim 2, characterized in that: The tannin content in the tannin source is not less than 66%.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the soybean protein to the tannin source is 1: (0.07-0.47).

5. The preparation method according to claim 4, characterized in that: The mass ratio of the soy protein to sodium phytate is 1:(0.07-1.5).

6. The preparation method according to claim 5, characterized in that: The mass ratio of the soy protein to sodium hydroxide is 1:(0.07-1).

7. The preparation method according to claim 6, characterized in that: The Tween-80 is added in an amount of 2-12% of the soybean protein.

8. The preparation method according to claim 1, characterized in that: In step S3, the rotation speed of the mechanical stirring is 900-1400 r / min.

9. A biomass soybean protein tannin foam plastic prepared by the preparation method according to any one of claims 1 to 8.

10. A flame retardant product, characterized in that: The biomass soybean protein tannin foam plastic comprises the biomass soybean protein tannin foam plastic as claimed in claim 9.

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