A polyvinyl butyral resin-based high-efficiency sound-absorbing material and preparation method thereof

Abstract

The present invention discloses a polyvinyl butyral resin-based high-efficiency sound-absorbing material and a preparation method thereof. The sound-absorbing material comprises a PVB resin, an ionic liquid and an isocyanate-terminated polyurea. The present invention also provides a preparation method thereof. Compared with the prior art, the sound-absorbing material prepared by the present invention has the advantages of good sound-absorbing effect, excellent mechanical properties, good heat resistance, etc.

Description

Technical Field

[0001] The invention relates to the field of polymer technology, and in particular to a polyvinyl butyral resin-based high-efficiency sound-absorbing material and a preparation method thereof. Background Art

[0002] CN108885862A discloses a sound-absorbing material and a method for preparing the same, comprising a fiber group consisting of inorganic fibers, organic fibers, or a mixed fiber of the inorganic fibers and the organic fibers, with the bonding points covered by a polymer covering film. The sound-absorbing material prepared by the method has a short service life and a low sound absorption effect of the fiber structure. CN112469773A discloses a composition for a sound-absorbing material and a method for preparing the same, comprising an epichlorohydrin polymer, a foaming agent, and a cross-linking agent, and preparing the epichlorohydrin polymer into a foaming material. The sound-absorbing material prepared by the method has a low structural strength. Summary of the invention

[0003] In view of the above-mentioned defects of the prior art, the object of the present invention is to provide a polyvinyl butyral resin-based high-efficiency sound-absorbing material with good sound-absorbing effect and good heat resistance.

[0004] The technical solution of the present invention is achieved in this way:

[0005] As a technical solution:

[0006] A method for preparing a polyvinyl butyral resin-based high-efficiency sound-absorbing material comprises the following steps:

[0007] S1: dissolving polyvinyl alcohol in water, adding n-butyraldehyde and 12-18% hydrochloric acid, and reacting at 13-18°C for 40-60 minutes; heating to 50-70°C and continuing to react for 4-6 hours; washing the precipitate with water, adding 30-38% NaOH aqueous solution, stirring evenly, and standing for 4-6 hours; taking the precipitate, washing with water, centrifuging, and drying to obtain PVB resin;

[0008] S2: dissolving the amine compound in a solvent; slowly adding diisocyanate in 2-4 batches, once every 20-40 minutes; reacting at 60-80° C. for 4-6 hours to obtain an isocyanate-terminated polyurea;

[0009] S3: the PVB resin obtained in step S2 and the ionic liquid are mixed evenly, and reacted at 80-140° C. and 30-80 rpm for 20-40 min; 1-10 parts of isocyanate-terminated polyurea are added and the reaction is continued at 80-140° C. and 30-80 rpm for 4-6 h;

[0010] S4: drying the product obtained in step S3 at 100-160° C. for 30-80 min to obtain the polyvinyl butyral resin-based high-efficiency sound-absorbing material.

[0011] Preferably, the method for preparing the polyvinyl butyral resin-based high-efficiency sound-absorbing material comprises the following steps, measured in parts by weight:

[0012] S1: Add 60-100 parts of water and 5-15 parts of polyvinyl alcohol into a reactor, stir at 90-100°C, 20-80rpm for 1-3h, then cool to room temperature, add 3-8 parts of n-butyraldehyde, cool to 13-18°C, add 0.5-2.5 parts of 12-18% hydrochloric acid, react for 40-60min, then heat to 50-70°C, react for 4-6h, take the precipitate, wash with water 3-6 times, add 30-38% NaOH aqueous solution, let stand for 4-6h, wash with water 3-6 times, centrifuge at 6000-8000rpm, take the precipitate, dry at 50-80°C for 6-8h, and obtain PVB resin;

[0013] S2: Weigh 5-10 parts of an amine compound and 20-40 parts of a solvent in a clean and dry reactor and stir at a speed of 30-80 rpm to completely dissolve the amine compound, slowly add 1-8 parts of a diisocyanate in 2-4 batches, once every 20-40 minutes; after the addition, set the temperature to 60-80°C, react at this temperature for 4-6 hours to obtain an isocyanate-terminated polyurea;

[0014] S3: Add 1-10 parts of PVB resin and 1-10 parts of ionic liquid into the reactor, react at 80-140°C, 30-80rpm, react for 20-40min, add 1-10 parts of isocyanate-terminated polyurea and react for 4-6h,

[0015] S4: Bake the product obtained in S3 at 100-160° C. for 30-80 min.

[0016] As a further embodiment of the present invention, the molecular weight of the polyvinyl alcohol is about 40,000-80,000.

[0017] As a further embodiment of the present invention, the amine compound is at least one of 4,4'-diaminodiphenyl ether, isophoronediamine, dimethyl-4-phenylenediamine, 4,4'-diaminobiphenyl, and diphenylethylenediamine.

[0018] As a further embodiment of the present invention, the solvent is at least one of dichloromethane, tetrahydrofuran, ethanol, N,N-dimethylformamide and N,N-dimethylacetamide.

[0019] As a further embodiment of the present invention, the diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.

[0020] As a further embodiment of the present invention, the ionic liquid is at least one of 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid and 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)imidazolium bis(trifluoromethanesulfonyl)imide ionic liquid. Preferably, the mass ratio of 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid and 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)imidazolium bis(trifluoromethanesulfonyl)imide ionic liquid is (1-5):(1-5).

[0021] As a further illustration of the present invention, the 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid is prepared by the following method: by weight, 1-3 parts of 1,4-dimethylpiperazine and 3-5 parts of 1,3-propane sultone are continuously stirred at 60-80° C. for 10-16 hours in 10-15 parts of ethyl acetate, cooled to room temperature, filtered, and the filter cake is dried at 50-70° C. for 5-8 hours to obtain an ionic liquid intermediate; 2-4 parts of p-toluenesulfonic acid and 1-3 parts of the ionic liquid intermediate are added to 0.1-0.3 parts of water, and stirred at 80-120° C. for 40-70 minutes until it becomes a yellow-brown viscous liquid.

[0022] As a further illustration of the present invention, the 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid has a double reaction center. In step S3, the hydroxyl group in the PVB resin may undergo nucleophilic substitution with the sulfonic acid group on the p-sulfopropyl group to form an ester or sulfate, or form a covalent bond through dehydration or dealcoholization reaction to achieve crosslinking between polymer chains; the oxygen atom on the sulfonic acid group in the ionic liquid may form a hydrogen bond with the hydroxyl group in the PVB resin. Although the hydrogen bond is not a covalent bond, it can provide a certain physical crosslinking effect for the material. The 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid has a double reaction center. The amino group in the polyurea may react with the sulfonic acid group in the ionic liquid as a nucleophilic reagent to form a new covalent bond to achieve crosslinking between polymer chains. The cation contained in the ionic liquid may form a complex between the PVB resin and the polyurea, further increasing the stability of the crosslinking, and the three form a precise three-dimensional network structure with long side chains and stable structure.

[0023] As a further illustration of the present invention, the 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl) imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid is prepared by the following method: by weight, 1-3 parts of acrylamide and 1-3 parts of imidazole are dissolved in 10-30 parts of toluene, and 0.1-0.3 parts of triethylamine are added, reacting at 100-140° C. for 12-16 hours, filtering, and the filter cake is 1-(3-amino-3-oxypropyl) imidazole; 3-5 parts of 1-(3-amino-3-oxypropyl) imidazole and 1-3 parts of Chloroacetamide is stirred in 5-10 parts of ethanol and stirred at 60-80°C for 16-24 hours. The filtered cake is 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride. Dissolve 1-3 parts of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride in 10-30 parts of water, add 2-4 parts of Ag[NTf2]Tf2, stir at room temperature for 3-5 hours, filter the precipitate AgCl, separate the layers, and dry the organic layer at 40-60°C for 2-4 hours to obtain the product.

[0024] As a further illustration of the present invention, the 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl) imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid has a double reaction center. In step S3, the hydroxyl group in the PVB resin may form a nucleophilic substitution product methyl carbamate with the amino group; the cationic part in the ionic liquid may form an ionic interaction with the hydroxyl group in the PVB resin, which helps to form a physical cross-linked network. The amino group in the ionic liquid may react with the isocyanate group to form a urea bond, and the oxyethyl group of the ionic liquid may participate in a nucleophilic addition reaction, especially on the isocyanate group, to form an addition product; the cationic part of the ionic liquid may form an ionic interaction with the polar group in the polyurea, which helps to form a stable network structure. The three constitute a precise three-dimensional network structure with a long branched chain and a stable structure.

[0025] The beneficial effects of the present invention are as follows: the PVB resin, polyurea and ionic liquid form a precise three-dimensional network structure with long side chains and stable structure, and the prepared sound-absorbing material has the advantages of good sound-absorbing effect, excellent mechanical properties, good heat resistance and the like. DETAILED DESCRIPTION

[0026] A polyvinyl butyral resin-based high-efficiency sound-absorbing material comprises the following steps:

[0027] S1: Add 60-100 parts of water and 5-15 parts of polyvinyl alcohol into a reactor, stir at 90-100°C, 20-80rpm for 1-3h, then cool to room temperature, add 3-8 parts of n-butyraldehyde, cool to 13-18°C, add 0.5-2.5 parts of 12-18% hydrochloric acid, react for 40-60min, then heat to 50-70°C, react for 4-6h, take the precipitate, wash with water 3-6 times, add 30-38% NaOH aqueous solution, let stand for 4-6h, wash with water 3-6 times, centrifuge at 6000-8000rpm, take the precipitate, dry at 50-80°C for 6-8h, and obtain PVB resin;

[0028] S2: Weigh 5-10 parts of an amine compound and 20-40 parts of a solvent in a clean and dry reactor and stir at a speed of 30-80 rpm to completely dissolve the amine compound, slowly add 1-8 parts of a diisocyanate in 2-4 batches, once every 20-40 minutes; after the addition is complete, set the temperature to 60-80° C., react at this temperature for 4-6 hours to obtain an isocyanate-terminated polyurea;

[0029] S3: Add 1-10 parts of PVB resin and 1-10 parts of ionic liquid into a reactor, react at 80-140°C, 30-80rpm, react for 20-40min, add 1-10 parts of isocyanate-terminated polyurea and react for 4-6h;

[0030] S4: Bake the product obtained in S3 at 100-160° C. for 30-80 min.

[0031] The PVB resin has good flexibility, low glass transition temperature, high tensile strength and impact strength due to the relatively long side chains in the PVB molecule. PVB has excellent transparency, good solubility, good light resistance, water resistance, heat resistance, cold resistance and film-forming properties. The hydroxyl content of the PVB resin prepared by the method is about 17%.

[0032] The polyurea is composed of amine compounds and isocyanate. The generated polyurea has a stable structure, a hydrogen bond effect between molecular chains, and excellent comprehensive mechanical properties. Even if it is immersed in various media such as water, acid, salt, and alkali for a long time, the performance will not be reduced.

[0033] The ionic liquid is at least one of 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid and 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)imidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid. Ionic liquids are a class of liquids composed entirely of cations and anions. They are liquid at room temperature or close to room temperature. This structural characteristic makes them highly designable and their physical and chemical properties can be adjusted as needed.

[0034] Table 1: Sources of some substances

[0035] name CAS Polyvinyl alcohol, molecular weight about 40000-80000 9002-89-5 4,4'-Diaminodiphenyl ether 101-80-4 Lysine diisocyanate 45172-15-4 1,4-Dimethylpiperazine 106-58-1 1,3-Propane sultone 1120-71-4 Ag[NTf2]Tf2 189114-61-2

[0036] Example 1

[0037] A polyvinyl butyral resin-based high-efficiency sound-absorbing material comprises the following steps:

[0038] S1: Add 7.7kg water and 800g polyvinyl alcohol into a reactor, stir at 90℃, 60rpm for 2h; add 448g n-butyraldehyde after cooling to room temperature; cool to 18℃, add 90g 18% hydrochloric acid and react for 60min; heat to 60℃ and react for 4h; take the precipitate, wash with water 6 times, add 35% NaOH aqueous solution and let stand for 6h, wash with water 6 times, centrifuge at 6000rpm, take the precipitate, dry at 60℃ for 6h, and obtain PVB resin;

[0039] S2: Weigh 500 g of 4,4'-diaminodiphenyl ether and 2 kg of ethanol, add them into a clean and dry reactor, stir at 30 rpm to completely dissolve 4,4'-diaminodiphenyl ether; slowly add 500 g of lysine diisocyanate in 2 batches, once every 20 minutes; after the addition, set the temperature to 60°C, react at this temperature for 4 hours to obtain isocyanate-terminated polyurea;

[0040] S3: 100 g of the PVB resin obtained in step S1 and 100 g of 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid were added to a reaction kettle, and reacted at 120° C. and 40 rpm for 30 min; 100 g of the isocyanate-terminated polyurea obtained in step S2 was added and the reaction was continued for 4 h;

[0041] S4: The product obtained in step S3 is baked at 140° C. for 60 min.

[0042] The 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid is prepared by the following method: 100 g of 1,4-dimethylpiperazine and 300 g of 1,3-propane sultone are continuously stirred at 80° C. for 10 h in 1.2 kg of ethyl acetate, cooled to room temperature, centrifuged at 6000 rpm, and the precipitate is dried at 60° C. for 6 h to obtain an ionic liquid intermediate. 300 g of p-toluenesulfonic acid and 200 g of the ionic liquid intermediate are added to 20 g of water, stirred at 100° C. for 60 min, until it becomes a yellow-brown viscous liquid, to obtain the ionic liquid intermediate.

[0043] Example 2

[0044] A polyvinyl butyral resin-based high-efficiency sound-absorbing material comprises the following steps:

[0045] S1: Add 7.7kg water and 800g polyvinyl alcohol into a reactor, stir at 90℃, 60rpm for 2h; add 448g n-butyraldehyde after cooling to room temperature; cool to 18℃, add 90g 18% hydrochloric acid and react for 60min; heat to 60℃ and react for 4h; take the precipitate, wash with water 6 times, add 35% NaOH aqueous solution and let stand for 6h, wash with water 6 times, centrifuge at 6000rpm, take the precipitate, dry at 60℃ for 6h, and obtain PVB resin;

[0046] S2: Weigh 500 g of 4,4'-diaminodiphenyl ether and 2 kg of ethanol, add them into a clean and dry reactor, stir at 30 rpm to completely dissolve 4,4'-diaminodiphenyl ether; slowly add 500 g of lysine diisocyanate in 2 batches, once every 20 minutes; after the addition, set the temperature to 60°C, react at this temperature for 4 hours to obtain isocyanate-terminated polyurea;

[0047] S3: 100 g of the PVB resin obtained in step S1 and 100 g of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl) imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid were added into a reactor and reacted at 120° C. and 40 rpm for 30 min, and 100 g of the isocyanate-terminated polyurea obtained in step S2 was added and reacted for 4 h;

[0048] S4: The product obtained in step S3 is baked at 140° C. for 60 min.

[0049] The 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl) imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid is prepared by the following method: 100 g of acrylamide and 100 g of imidazole are dissolved in 2 kg of toluene, and 20 g of triethylamine is added, reacting at 120° C. for 12 h, and centrifuging at 6000 rpm to obtain a precipitate to obtain 1-(3-amino-3-oxypropyl) imidazole; 300 g of 1-(3-amino-3-oxypropyl) imidazole and 100 g of chloroacetamide are dissolved in 1 kg of toluene to obtain a 1-(3-amino-3-oxypropyl) imidazole ionic liquid; The mixture was stirred in ethanol at 80 °C for 16 h, centrifuged at 6000 rpm, and precipitated to obtain 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride; 100 g of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride was dissolved in 1 kg of water, 200 g of Ag[NTf2]Tf2 was added, and the mixture was stirred at room temperature for 4 h. After filtering the precipitate AgCl, the layers were separated, and the organic layer was dried at 60 °C for 4 h.

[0050] Example 3

[0051] A polyvinyl butyral resin-based high-efficiency sound-absorbing material comprises the following steps:

[0052] S1: Add 7.7kg water and 800g polyvinyl alcohol into a reactor, stir at 90℃, 60rpm for 2h; add 448g n-butyraldehyde after cooling to room temperature; cool to 18℃, add 90g 18% hydrochloric acid and react for 60min; heat to 60℃ and react for 4h; take the precipitate, wash it with water 6 times, add 35% NaOH aqueous solution and let it stand for 6h, wash it with water 6 times, centrifuge it at 6000rpm, take the precipitate, dry it at 60℃ for 6h, and obtain PVB resin;

[0053] S2: Weigh 500 g of 4,4'-diaminodiphenyl ether and 2 kg of ethanol, add them into a clean and dry reactor, stir at 30 rpm to completely dissolve 4,4'-diaminodiphenyl ether; slowly add 500 g of lysine diisocyanate in 2 batches, once every 20 minutes; after the addition, set the temperature to 60°C, react at this temperature for 4 hours to obtain isocyanate-terminated polyurea;

[0054] S3: 100 g of the PVB resin obtained in step S1, 50 g of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)imidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid and 50 g of 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate salt ionic liquid were added into a reactor at 120° C., 40 rpm, and reacted for 30 min. 100 g of the isocyanate-terminated polyurea obtained in step S2 was added and reacted for 4 h.

[0055] S4: The product obtained in step S3 is baked at 140° C. for 60 min.

[0056] The 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid is prepared by the following method: 100 g of 1,4-dimethylpiperazine and 300 g of 1,3-propane sultone are continuously stirred at 80° C. for 10 h in 1.2 kg of ethyl acetate, cooled to room temperature, centrifuged at 6000 rpm, and the precipitate is dried at 60° C. for 6 h to obtain an ionic liquid intermediate. 300 g of p-toluenesulfonic acid and 200 g of the ionic liquid intermediate are added to 20 g of water, stirred at 100° C. for 60 min, until it becomes a yellow-brown viscous liquid, to obtain the ionic liquid intermediate.

[0057] The 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl) imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid is prepared by the following method: 100 g of acrylamide and 100 g of imidazole are dissolved in 2 kg of toluene, and 20 g of triethylamine is added, reacting at 120° C. for 12 h, and centrifuging at 6000 rpm to obtain a precipitate to obtain 1-(3-amino-3-oxypropyl) imidazole; 300 g of 1-(3-amino-3-oxypropyl) imidazole and 100 g of chloroacetamide are dissolved in 1 kg of toluene to obtain a 1-(3-amino-3-oxypropyl) imidazole ionic liquid; The mixture was stirred in ethanol at 80 °C for 16 h, centrifuged at 6000 rpm, and precipitated to obtain 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride; 100 g of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride was dissolved in 1 kg of water, 200 g of Ag[NTf2]Tf2 was added, and the mixture was stirred at room temperature for 4 h. After filtering the precipitate AgCl, the layers were separated, and the organic layer was dried at 60 °C for 4 h.

[0058] Example 4

[0059] A polyvinyl butyral resin-based high-efficiency sound-absorbing material comprises the following steps:

[0060] S1: Add 7.7kg water and 800g polyvinyl alcohol into a reactor, stir at 90℃, 60rpm for 2h; add 448g n-butyraldehyde after cooling to room temperature; cool to 18℃, add 90g 18% hydrochloric acid and react for 60min; heat to 60℃ and react for 4h; take the precipitate, wash with water 6 times, add 35% NaOH aqueous solution and let stand for 6h, wash with water 6 times, centrifuge at 6000rpm, take the precipitate, dry at 60℃ for 6h, and obtain PVB resin;

[0061] S2: Weigh 500 g of 4,4'-diaminodiphenyl ether and 2 kg of ethanol, add them into a clean and dry reactor, stir at 30 rpm to completely dissolve 4,4'-diaminodiphenyl ether; slowly add 500 g of lysine diisocyanate in 2 batches, once every 20 minutes; after the addition, set the temperature to 60°C, react at this temperature for 4 hours to obtain isocyanate-terminated polyurea;

[0062] S3: 500 g of the PVB resin obtained in step S1, 50 g of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)imidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid and 50 g of 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate salt ionic liquid were added into a reactor at 120° C. and 40 rpm for 30 min, and 100 g of the isocyanate-terminated polyurea obtained in step S2 was added for 4 h;

[0063] S4: The product obtained in step S3 is baked at 140° C. for 60 min.

[0064] The 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid is prepared by the following method: 100 g of 1,4-dimethylpiperazine and 300 g of 1,3-propane sultone are continuously stirred at 80° C. for 10 h in 1.2 kg of ethyl acetate, cooled to room temperature, centrifuged at 6000 rpm, and the precipitate is dried at 60° C. for 6 h to obtain an ionic liquid intermediate. 300 g of p-toluenesulfonic acid and 200 g of the ionic liquid intermediate are added to 20 g of water, stirred at 100° C. for 60 min, until it becomes a yellow-brown viscous liquid, to obtain the ionic liquid intermediate.

[0065] The 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl) imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid is prepared by the following method: 100 g of acrylamide and 100 g of imidazole are dissolved in 2 kg of toluene, and 20 g of triethylamine is added, reacting at 120° C. for 12 h, and centrifuging at 6000 rpm to obtain a precipitate to obtain 1-(3-amino-3-oxypropyl) imidazole; 300 g of 1-(3-amino-3-oxypropyl) imidazole and 100 g of chloroacetamide are dissolved in 1 kg of toluene to obtain a 1-(3-amino-3-oxypropyl) imidazole ionic liquid; The mixture was stirred in ethanol at 80 °C for 16 h, centrifuged at 6000 rpm, and precipitated to obtain 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride; 100 g of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride was dissolved in 1 kg of water, 200 g of Ag[NTf2]Tf2 was added, and the mixture was stirred at room temperature for 4 h. After filtering the precipitate AgCl, the layers were separated, and the organic layer was dried at 60 °C for 4 h.

[0066] Example 5

[0067] A polyvinyl butyral resin-based high-efficiency sound-absorbing material comprises the following steps:

[0068] S1: Add 7.7kg water and 800g polyvinyl alcohol into a reactor, stir at 90℃, 60rpm for 2h; add 448g n-butyraldehyde after cooling to room temperature; cool to 18℃, add 90g 18% hydrochloric acid and react for 60min; heat to 60℃ and react for 4h; take the precipitate, wash with water 6 times, add 35% NaOH aqueous solution and let stand for 6h, wash with water 6 times, centrifuge at 6000rpm, take the precipitate, dry at 60℃ for 6h, and obtain PVB resin;

[0069] S2: Weigh 500 g of 4,4'-diaminodiphenyl ether and 2 kg of ethanol, add them into a clean and dry reactor, stir at 30 rpm to completely dissolve 4,4'-diaminodiphenyl ether; slowly add 500 g of lysine diisocyanate in 2 batches, once every 20 minutes; after the addition, set the temperature to 60°C, react at this temperature for 4 hours to obtain isocyanate-terminated polyurea;

[0070] S3: 100 g of the PVB resin obtained in step S1, 50 g of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)imidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid and 50 g of 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate salt ionic liquid were added into a reactor at 120° C., 40 rpm, and reacted for 30 min. 500 g of the isocyanate-terminated polyurea obtained in step S2 was added and reacted for 4 h.

[0071] S4: The product obtained in step S3 is baked at 140° C. for 60 min.

[0072] The 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid is prepared by the following method: 100 g of 1,4-dimethylpiperazine and 300 g of 1,3-propane sultone are continuously stirred at 80° C. for 10 h in 1.2 kg of ethyl acetate, cooled to room temperature, centrifuged at 6000 rpm, and the precipitate is dried at 60° C. for 6 h to obtain an ionic liquid intermediate. 300 g of p-toluenesulfonic acid and 200 g of the ionic liquid intermediate are added to 20 g of water, stirred at 100° C. for 60 min, until it becomes a yellow-brown viscous liquid, to obtain the ionic liquid intermediate.

[0073] The 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl) imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid is prepared by the following method: 100 g of acrylamide and 100 g of imidazole are dissolved in 2 kg of toluene, and 20 g of triethylamine is added, reacting at 120° C. for 12 h, and centrifuging at 6000 rpm to obtain a precipitate to obtain 1-(3-amino-3-oxypropyl) imidazole; 300 g of 1-(3-amino-3-oxypropyl) imidazole and 100 g of chloroacetamide are dissolved in 1 kg of toluene to obtain a 1-(3-amino-3-oxypropyl) imidazole ionic liquid; The mixture was stirred in ethanol at 80 °C for 16 h, centrifuged at 6000 rpm, and precipitated to obtain 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride; 100 g of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)-imidazole chloride was dissolved in 1 kg of water, 200 g of Ag[NTf2]Tf2 was added, and the mixture was stirred at room temperature for 4 h. After filtering the precipitate AgCl, the layers were separated, and the organic layer was dried at 60 °C for 4 h.

[0074] Comparative Example 1

[0075] Ultra-fine glass wool, thickness 5cm, density 24kg / m 3 .

[0076] Comparative Example 2

[0077] Polyurethane foam, thickness 5cm, density 45kg / m 3 .

[0078] Test Example 1

[0079] The sound absorption coefficients of the sound absorbing materials of Examples 1 to 8 were tested at different audio frequencies in accordance with the standard GB / T 20247-2006 “Sound absorption measurement in acoustic reverberation chambers”.

[0080] Table 2: Sound absorption coefficient

[0081]

[0082] By comparing Example 1-5 with Comparative Example 1-2, it can be found that the sound absorption effect of Example 1-5 is better than that of Comparative Example 1-2. The possible reason is that Example 1-5 is a precise three-dimensional network structure with a relatively long branch chain and a stable structure formed by PVB resin, polyurea and ionic liquid. The main sound absorption principle of Comparative Example 1-2 is to absorb sound by the porous structure of the material. The sound-absorbing material obtained by the method of Example 1-5 has a precise and stable three-dimensional structure. After the sound wave enters the material, it is reflected, refracted and scattered in the gap, thereby consuming sound energy; the relatively long branch chain structure may provide a complex path, increase the propagation path, time, surface area and internal friction of the sound wave inside the material, and contribute to the consumption of sound wave energy; the presence of ion complexes increases the reflection, refraction and scattering of sound waves in the gap, thereby consuming sound energy.

[0083] Test Example 2

[0084] The samples of Examples 1-5 were weighed accurately to a weight of 0.0500 g and subjected to thermogravimetric analysis using TGA Q5000 (TA Company, USA) at a heating rate of 10°C / min over a temperature range of 20-800°C. The temperatures at which the weight loss was 5% and 10% were recorded as T 5 / ℃ and T 10 / ℃, the residual weight when the temperature rises to 800℃ is recorded as Y C (800℃) / %.

[0085] Table 3: Thermal performance parameters

[0086] serial number <![CDATA[T 5 / ℃]]> <![CDATA[T 10 / ℃]]> <![CDATA[Y C (800℃) / % <!-- 7 -->]]> Example 1 331 420 27.75 Example 2 339 429 28.66 Example 3 372 457 35.69 Example 4 351 435 30.18 Example 5 354 437 30.45

[0087] By comparing Examples 1-5, it can be found that Example 3 has the highest thermal stability. 5 / ℃ is 372℃, T10 / ℃ is 457℃, Y C (800℃) / % is 35.69%. The possible reason is that Example 3 uses a mixture of 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)imidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid and 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate salt ionic liquid. The strong interaction between cations and anions improves the thermal stability, and is more suitable than the ratio of PVB resin and polyurea. Under this ratio, the cross-linking density of the three-dimensional network is the highest, and the network formed is the most stable, thereby improving the thermal stability.

Claims

1. A method for preparing a polyvinyl butyral resin-based high-efficiency sound-absorbing material, characterized in that: The following steps are involved: S1: Dissolve polyvinyl alcohol in water, add n-butyraldehyde and 12-18% hydrochloric acid, and react at 13-18°C for 40-60 minutes; After heating to 50-70°C, continue the reaction for 4-6 hours; wash the precipitate with water, add 30-38% NaOH aqueous solution, stir evenly, and let stand for 4-6 hours; take the precipitate, wash with water, centrifuge, and dry to obtain PVB resin; S2: dissolving the amine compound in a solvent; slowly adding diisocyanate in 2-4 batches, once every 20-40 minutes; reacting at 60-80° C. for 4-6 hours to obtain an isocyanate-terminated polyurea; S3: the PVB resin obtained in step S2 and the ionic liquid are mixed evenly, and reacted at 80-140° C. and 30-80 rpm for 20-40 min; 1-10 parts of isocyanate-terminated polyurea are added and the reaction is continued at 80-140° C. and 30-80 rpm for 4-6 h; S4: baking the product obtained in step S3 at 100-160° C. for 30-80 min to obtain the polyvinyl butyral resin-based high-efficiency sound-absorbing material.

2. The method for preparing a polyvinyl butyral resin-based high-efficiency sound-absorbing material according to claim 1, characterized in that: The method comprises the following steps, in parts by weight: S1: Add 60-100 parts of water and 5-15 parts of polyvinyl alcohol into a reaction kettle, stir at 90-100°C and 20-80rpm for 1-3h, then cool to room temperature; add 3-8 parts of n-butyraldehyde, cool to 13-18°C, add 0.5-2.5 parts of 12-18% hydrochloric acid, react for 40-60min; heat to 50-70°C and react for 4-6h; take the precipitate, wash with water 3-6 times, add 30-38% NaOH aqueous solution, let stand for 4-6h, wash with water 3-6 times, centrifuge at 6000-8000rpm, take the precipitate, and dry at 50-80°C for 6-8h to obtain PVB resin; S2: Weigh 5-10 parts of an amine compound and 20-40 parts of a solvent into a clean and dry reactor, and completely dissolve the amine compound under stirring at 30-80 rpm; slowly add 1-8 parts of a diisocyanate in 2-4 batches, once every 20-40 minutes; after the addition, set the temperature to 60-80°C, react at this temperature for 4-6 hours, and obtain an isocyanate-terminated polyurea; S3: Add 1-10 parts of PVB resin and 1-10 parts of ionic liquid into a reaction kettle, react at 80-140° C. and 30-80 rpm for 20-40 min, add 1-10 parts of isocyanate-terminated polyurea and react for 4-6 h; S4: Bake the product obtained in S3 at 100-160° C. for 30-80 min.

3. The method for preparing a polyvinyl butyral resin-based high-efficiency sound-absorbing material according to claim 1 or 2, characterized in that: The amine compound is at least one of 4,4'-diaminodiphenyl ether, isophorone diamine, dimethyl-4-phenylenediamine, 4,4'-diaminobiphenyl and diphenylethylenediamine.

4. The method for preparing a polyvinyl butyral resin-based high-efficiency sound-absorbing material according to claim 1 or 2, characterized in that: The solvent is at least one of dichloromethane, tetrahydrofuran, ethanol, N,N-dimethylformamide and N,N-dimethylacetamide.

5. The method for preparing a polyvinyl butyral resin-based high-efficiency sound-absorbing material according to claim 1 or 2, characterized in that: The diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate.

6. The method for preparing a polyvinyl butyral resin-based high-efficiency sound-absorbing material according to claim 1 or 2, characterized in that: The ionic liquid is at least one of 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine p-toluenesulfonate ionic liquid and 1-(3-amino-3-oxypropyl)-3-(2-amino-2-oxyethyl)imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid.

7. A polyvinyl butyral resin-based high-efficiency sound-absorbing material, characterized in that: The method is prepared by any one of claims 1 to 6.

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