A bio-based flame retardant plasticizer and its preparation method and application

Abstract

The invention discloses a bio-based flame retardant plasticizer and a preparation method and application thereof, and relates to the technical field of flame retardants and plasticizers. The invention uses sodium alginate and tris(4-aminophenyl)thiophosphate as raw materials to synthesize the bio-based flame retardant plasticizer in a one-step method through an amidation reaction. The bio-based flame retardant plasticizer is not only biodegradable, but also has both plasticizing and flame retardant functions, and does not need to add a plasticizer and a flame retardant separately. The bio-based flame retardant plasticizer has good compatibility with polyvinyl alcohol, and does not need to use a compatibilizer. The invention can also solve the problem that a conventional flame retardant seriously affects the mechanical properties of a polyvinyl alcohol composite material due to a large amount of conventional flame retardants added.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardants and plasticizers, and in particular to a bio-based flame retardant plasticizer and a preparation method and application thereof. Background Art

[0002] Most polymer materials are composed of carbon and hydrogen elements and are easy to burn. Plastic films are easy to burn because of their large surface area and easy heat conduction. In recent years, with the rapid development of high-tech fields such as new energy vehicles, advanced photovoltaics, new energy storage, and artificial intelligence, higher requirements have been placed on the flame retardant properties of plastic films and the environmental performance of flame retardants. It is urgent to develop new environmentally friendly flame retardant plastic films that have excellent physical and mechanical properties and flame retardant properties to meet the needs of the rapidly developing high-tech fields for high-performance polymer functional films.

[0003] As an environmentally friendly polymer material with excellent comprehensive performance, polyvinyl alcohol (PVA) has a wide range of theoretical applications, but because its melting point (226°C) and decomposition temperature (230-250°C) are very close, it is difficult to process by thermoplastics. In addition, the limiting oxygen index (LOI) of PVA is only 20%, which is very easy to ignite and accompanied by molten droplets, and there are great safety hazards in actual use. Therefore, improving the thermoplastic processability of PVA and preparing environmentally friendly film products with excellent mechanical and flame retardant properties are of great significance to broadening the application of PVA and controlling plastic pollution. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a bio-based flame retardant plasticizer and a preparation method thereof, using sodium alginate, a byproduct of extracting iodine and mannitol from kelp or giant kelp of brown algae, as a raw material, which not only realizes the high-value utilization of sodium alginate and expands its application range, but also the prepared bio-based flame retardant plasticizer exhibits excellent flame retardant and plasticizing effects and is biodegradable.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0006] One of the purposes of the present invention is to provide a bio-based flame retardant plasticizer, which is prepared by amidation reaction of sodium alginate and tris(4-aminophenyl)thiophosphate.

[0007] The second object of the present invention is to provide a method for preparing the bio-based flame retardant plasticizer, comprising the following steps:

[0008] (1) dissolving sodium alginate in dilute hydrochloric acid to obtain solution I;

[0009] (2) dissolving the catalyst in water to obtain solution II;

[0010] (3) dissolving tris(4-aminophenyl)phosphorothioate in an organic solvent to obtain a solution III;

[0011] (4) Solution I and Solution II are fully mixed, and then Solution III is added to react. After the reaction is completed, the reaction solution is distilled under reduced pressure to remove the solvent, and the residue is washed with water and dried to obtain a bio-based flame retardant plasticizer.

[0012] The third object of the present invention is to provide the use of the bio-based flame retardant plasticizer in a polyvinyl alcohol composite material.

[0013] The beneficial effects of the present invention are:

[0014] 1. The present invention uses sodium alginate and tris(4-aminophenyl)thiophosphate as raw materials to synthesize a bio-based flame retardant plasticizer through an amidation reaction in a one-step method. Compared with traditional phthalate plasticizers, the bio-based flame retardant plasticizer of the present invention can exert a better plasticizing effect and has a certain biodegradability.

[0015] 2. The bio-based flame retardant plasticizer of the present invention has both plasticizing and flame retardant functions, and there is no need to add plasticizers and flame retardants separately. It has good compatibility with polyvinyl alcohol and does not require the use of a compatibilizer. It can also solve the problem that conventional flame retardants seriously affect the mechanical properties of polyvinyl alcohol composites due to large addition amounts. DETAILED DESCRIPTION

[0016] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0017] The present invention provides a bio-based flame retardant plasticizer, which is prepared by amidation reaction of sodium alginate and tris(4-aminophenyl)phosphorothioate. Both sodium alginate and tris(4-aminophenyl)phosphorothioate can be purchased commercially, and the novel bio-based flame retardant plasticizer can be synthesized by a one-step reaction.

[0018] The present invention provides a method for preparing the bio-based flame retardant plasticizer, comprising the following steps:

[0019] (1) dissolving sodium alginate in dilute hydrochloric acid to obtain solution I;

[0020] (2) dissolving the catalyst in water to obtain solution II;

[0021] (3) dissolving tris(4-aminophenyl)phosphorothioate in an organic solvent to obtain a solution III;

[0022] (4) Solution I and Solution II are fully mixed, and then Solution III is added to react. After the reaction is completed, the reaction solution is distilled under reduced pressure to remove the solvent, and the residue is washed with water and dried to obtain a bio-based flame retardant plasticizer.

[0023] Furthermore, the molecular weight of the sodium alginate is 5000 to 8000. In the present invention, the reaction raw material is preferably low molecular weight sodium alginate.

[0024] Furthermore, the pH value of the dilute hydrochloric acid is 4 to 5. Sodium alginate is dissolved in the dilute hydrochloric acid to prepare a sodium alginate solution.

[0025] Furthermore, the catalyst is 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Both EDC and NHS are carboxylic acid activation reagents. EDC reacts with carboxylic acid to generate an unstable intermediate product O-acylurea, and NHS reacts with carboxylic acid to generate an activated ester. Both the intermediate product and the activated ester have high reactivity and can undergo nucleophilic addition reaction with amino groups to form a stable amide bond.

[0026] Furthermore, the organic solvent is at least one of ethanol, methanol and acetone. These organic solvents have a low boiling point and can be recovered and reused by vacuum distillation during post-processing, thereby reducing costs; and these organic solvents are miscible with water, and the residual organic solvent after vacuum distillation can be removed by washing with water.

[0027] Furthermore, the molar ratio of sodium alginate to EDC and NHS is 1:(0.5-1.5):(0.5-1.5), wherein the molar amount of sodium alginate is calculated based on its sodium carboxylate group.

[0028] Furthermore, the molar ratio of tris(4-aminophenyl)thiophosphate to sodium alginate is 1:(3-4), wherein the molar amount of sodium alginate is calculated based on its sodium carboxylate group.

[0029] The invention provides application of the bio-based flame retardant plasticizer in a polyvinyl alcohol composite material.

[0030] The invention provides a polyvinyl alcohol composite material, comprising polyvinyl alcohol and the bio-based flame retardant plasticizer.

[0031] Furthermore, the polyvinyl alcohol composite material also includes an inorganic filler. Specifically, the inorganic filler can be an inorganic filler well known to those skilled in the art, including but not limited to at least one of calcium carbonate, talc, mica powder, silicon dioxide, kaolin, diatomaceous earth, white carbon black, and carbon black. The purpose of adding an inorganic filler to the composite material is to improve the mechanical properties, heat resistance, and flame retardancy of the composite material.

[0032] Furthermore, the polyvinyl alcohol composite material further comprises an anti-ultraviolet agent. Specifically, the anti-ultraviolet agent may be an anti-ultraviolet agent well known to those skilled in the art, including but not limited to at least one of a benzophenone anti-ultraviolet agent and a benzotriazole anti-ultraviolet agent. The purpose of adding an anti-ultraviolet agent to the composite material is to inhibit and delay the light aging of the composite material caused by ultraviolet rays, and to improve the durability of the composite material.

[0033] Furthermore, the polyvinyl alcohol composite material also includes an antioxidant. Specifically, the antioxidant can be an antioxidant well known to those skilled in the art, including but not limited to at least one of a phenolic antioxidant and an amine antioxidant. The purpose of adding an antioxidant to the composite material is to delay the oxidation process of the composite material, thereby extending the service life of the composite material.

[0034] The sodium alginate used in the following examples and comparative examples was purchased from Qingdao Jingyan Biotechnology Development Co., Ltd.

[0035] Example 1

[0036] 10 g of sodium alginate (molecular weight of 5000) was dissolved in dilute hydrochloric acid (pH=5) to obtain a solution I with a mass concentration of 1%; EDC and NHS were dissolved in water to obtain a solution II; tris(4-aminophenyl)thiophosphate was dissolved in ethanol to obtain a solution III; wherein the molar ratio of sodium alginate to EDC and NHS was 1:1:0.5, the molar ratio of tris(4-aminophenyl)thiophosphate to sodium alginate was 1:3, and the molar amount of sodium alginate was calculated based on its sodium carboxylate group; solution I was fully mixed with solution II, and then solution III was added for reaction, and after the reaction was completed, the reaction solution was distilled under reduced pressure to remove the solvent, the residue was washed with water, and vacuum dried to obtain a bio-based flame retardant plasticizer.

[0037] Example 2

[0038] 10 g of sodium alginate (molecular weight of 5000) was dissolved in dilute hydrochloric acid (pH=4) to obtain a solution I with a mass concentration of 1.5%; EDC and NHS were dissolved in water to obtain a solution II; tris(4-aminophenyl)thiophosphate was dissolved in ethanol to obtain a solution III; wherein the molar ratio of sodium alginate to EDC and NHS was 1:1:1, the molar ratio of tris(4-aminophenyl)thiophosphate to sodium alginate was 1:3.5, and the molar amount of sodium alginate was calculated based on its sodium carboxylate group; solution I was fully mixed with solution II, and then solution III was added for reaction, and after the reaction was completed, the reaction solution was distilled under reduced pressure to remove the solvent, the residue was washed with water, and vacuum dried to obtain a bio-based flame retardant plasticizer.

[0039] Example 3

[0040] 10 g of sodium alginate (molecular weight of 8000) was dissolved in dilute hydrochloric acid (pH=4) to obtain a solution I with a mass concentration of 1%; EDC and NHS were dissolved in water to obtain a solution II; tris(4-aminophenyl)thiophosphate was dissolved in ethanol to obtain a solution III; wherein the molar ratio of sodium alginate to EDC and NHS was 1:0.5:1, the molar ratio of tris(4-aminophenyl)thiophosphate to sodium alginate was 1:4, and the molar amount of sodium alginate was calculated based on its sodium carboxylate group; solution I was fully mixed with solution II, and then solution III was added to react, and after the reaction was completed, the reaction solution was distilled under reduced pressure to remove the solvent, the residue was washed with water, and vacuum dried to obtain a bio-based flame retardant plasticizer.

[0041] Example 4

[0042] 10 g of sodium alginate (molecular weight of 8000) was dissolved in dilute hydrochloric acid (pH=4.5) to obtain a solution I with a mass concentration of 1%; EDC and NHS were dissolved in water to obtain a solution II; tris(4-aminophenyl)thiophosphate was dissolved in ethanol to obtain a solution III; wherein the molar ratio of sodium alginate to EDC and NHS was 1:1.5:0.5, the molar ratio of tris(4-aminophenyl)thiophosphate to sodium alginate was 1:3.5, and the molar amount of sodium alginate was calculated based on its sodium carboxylate group; solution I was fully mixed with solution II, and then solution III was added for reaction, and after the reaction was completed, the reaction solution was distilled under reduced pressure to remove the solvent, the residue was washed with water, and vacuum dried to obtain a bio-based flame retardant plasticizer.

[0043] Example 5

[0044] 10 g of sodium alginate (molecular weight of 5000) was dissolved in dilute hydrochloric acid (pH=4) to obtain a solution I with a mass concentration of 2%; EDC and NHS were dissolved in water to obtain a solution II; tris(4-aminophenyl)thiophosphate was dissolved in ethanol to obtain a solution III; wherein the molar ratio of sodium alginate to EDC and NHS was 1:1.2:0.5, the molar ratio of tris(4-aminophenyl)thiophosphate to sodium alginate was 1:4, and the molar amount of sodium alginate was calculated based on its sodium carboxylate group; solution I was fully mixed with solution II, and then solution III was added for reaction, and after the reaction was completed, the reaction solution was distilled under reduced pressure to remove the solvent, the residue was washed with water, and vacuum dried to obtain a bio-based flame retardant plasticizer.

[0045] The bio-based flame retardant plasticizers obtained in the above-mentioned Examples 1 to 5 are respectively applied to the preparation of polyvinyl alcohol film, and the specific preparation method is as follows: 80 parts of polyvinyl alcohol (polymerization degree of 2000, alcoholysis degree of 92%), 15 parts of bio-based flame retardant plasticizer, 15 parts of calcium carbonate, 10 parts of talc and 5 parts of polyethylene wax are added to a high-speed mixer, and mixed for 5 minutes at a speed of 1000r / min and a temperature of 60°C to obtain a premix; then the premix is ​​melted, extruded and granulated by a twin-screw extruder at a speed of 350r / min and a temperature of 140-180°C to obtain a polyvinyl alcohol composite material; finally, the polyvinyl alcohol composite material is added to a film blowing machine, and melted, extruded, blown, pulled and wound at a speed of 300r / min, a temperature of 140-180°C and an aspect ratio of 20 to obtain a polyvinyl alcohol film. The prepared polyvinyl alcohol film is subjected to performance tests, and the test results are shown in Table 1.

[0046] The longitudinal tensile strength and elongation at break of the film were tested according to standard GB / T 1040.3-2006; the oxygen index of the film was tested according to standard GB / T 2406.2-2009.

[0047] Table 1 Performance test results of polyvinyl alcohol film

[0048] Tensile strength(MPa) Elongation at break (%) Oxygen index (%) Example 1 42.5 134.7 30.8 Example 2 43.8 125.1 31.2 Example 3 41.6 132.9 30.4 Example 4 45.9 128.0 32.0 Example 5 44.7 137.2 31.6 Comparative Example 1 30.2 96.4 26.7 Comparative Example 2 28.5 92.3 25.8 Comparative Example 3 27.1 89.5 27.5 Comparative Example 4 35.4 103.8 25.2

[0049] In Table 1, Comparative Example 1 is a mixture of sodium alginate and tris(4-aminophenyl)thiophosphate in a molar ratio of 1:4 replacing the bio-based flame retardant plasticizer; Comparative Example 2 is sodium alginate as a plasticizer; Comparative Example 3 is tris(4-aminophenyl)thiophosphate as a flame retardant; Comparative Example 4 is dioctyl phthalate as a plasticizer.

[0050] It can be seen from Table 1 that, compared with the comparative example, the bio-based flame retardant plasticizer prepared in the example has excellent flame retardant and plasticizing effects, and can substantially improve the flame retardant properties and mechanical properties of the polyethylene composite material.

[0051] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A bio-based flame retardant plasticizer, characterized in that: It is prepared by amidation reaction of sodium alginate and tri(4-aminophenyl)thiophosphate.

2. A method for preparing a bio-based flame retardant plasticizer, characterized in that: The preparation method comprises the following steps: (1) dissolving sodium alginate in dilute hydrochloric acid to obtain solution I; (2) dissolving the catalyst in water to obtain solution II; (3) dissolving tris(4-aminophenyl)phosphorothioate in an organic solvent to obtain a solution III; (4) Solution I and Solution II are fully mixed, and then Solution III is added to react. After the reaction is completed, the reaction solution is distilled under reduced pressure to remove the solvent, and the residue is washed with water and dried to obtain a bio-based flame retardant plasticizer.

3. The method for preparing a bio-based flame retardant plasticizer according to claim 1 or 2, characterized in that: The molecular weight of the sodium alginate is 5000-8000.

4. The method for preparing a bio-based flame retardant plasticizer according to claim 2, characterized in that: The pH value of the dilute hydrochloric acid is 4-5.

5. The method for preparing a bio-based flame retardant plasticizer according to claim 2, characterized in that: The catalysts are EDC and NHS.

6. The method for preparing a bio-based flame retardant plasticizer according to claim 2, characterized in that: The organic solvent is at least one of ethanol, methanol and acetone.

7. The method for preparing a bio-based flame retardant plasticizer according to claim 5, characterized in that: The molar ratio of sodium alginate to EDC and NHS is 1:(0.5-1.5):(0.5-1.5), wherein the molar amount of sodium alginate is calculated based on its sodium carboxylate group.

8. The method for preparing a bio-based flame retardant plasticizer according to claim 1 or 2, characterized in that: The molar ratio of tris(4-aminophenyl)thiophosphate to sodium alginate is 1:(3-4), wherein the molar amount of sodium alginate is calculated based on its sodium carboxylate group.

9. Use of the bio-based flame retardant plasticizer according to claim 1 or the bio-based flame retardant plasticizer prepared by the preparation method according to any one of claims 2 to 8 in polyvinyl alcohol composite materials.

10. A polyvinyl alcohol composite material, characterized in that: The polyvinyl alcohol composite material comprises polyvinyl alcohol and the bio-based flame retardant plasticizer according to claim 1 or the bio-based flame retardant plasticizer prepared by the preparation method according to any one of claims 2 to 8.