Preparation method of composite sound-absorbing material for motor home

Abstract

The invention discloses a preparation method of a composite sound-absorbing material for a motor home, and relates to the technical field of sound-absorbing materials, the preparation method comprises the following steps: S1, preparing a functional polymer; step S2, modifying the graphene sponge; step S3, preparation of functional fibers; step S4, surface modification; and S5, preparing the composite sound-absorbing material. The composite sound-absorbing material is good in weather resistance and mechanical property and remarkable in sound-absorbing effect.

Description

Technical Field

[0001] The invention relates to the technical field of sound absorbing materials, and in particular to a method for preparing a composite sound absorbing material for a recreational vehicle. Background Art

[0002] With the development of the automobile industry, people's demand for RVs is increasing. As a high-end car, RVs have higher requirements for comfort, safety, and customer experience than ordinary cars. Among them, the noise control of RVs during driving has attracted more and more attention. As a noise countermeasure, sound-absorbing materials are applied to the walls of the hood, instrument panel, ceiling material, door interior panels, cab floor, etc.

[0003] Sound-absorbing materials can be divided into two categories: porous sound-absorbing materials and resonant sound-absorbing structural materials. The types of sound-absorbing materials for RVs on the market are mainly porous sound-absorbing materials, mainly because porous materials are widely available and easy to process. General porous sound-absorbing materials have the advantages of large high-frequency sound absorption coefficient and small specific gravity, but this type of material is not suitable for absorbing lower frequency sounds. In addition, commonly used porous sound-absorbing materials include glass fiber sound-absorbing cotton, rock wool, rubber and plastic sound-absorbing cotton, sponge, foam, etc., which have the disadvantages of being environmentally unfriendly and having unstable sound absorption performance.

[0004] In order to solve the above problems, the Chinese invention patent with the authorization announcement number CN112080856B discloses a method for preparing a composite sound-absorbing material for RVs, comprising the following steps: Step S1: preparing the molten main material: taking 40-60 parts of PP, 10-15 parts of PET, and 5-10 parts of polyethylene terephthalate by weight, respectively, chopping and mixing to form a mixture and stirring evenly; Step S2: melt extrusion; Step S3: forming the main material fiber; Step S4: preparing the auxiliary material fiber; Step S5: mixing the main and auxiliary material fibers; Step S6: preparing the fiber sound-absorbing material: the main material fiber and the auxiliary material fiber form a fiber sound-absorbing material with a mesh structure on the centrifugal cotton mesh surface along with the high-speed hot air flow. The composite sound-absorbing material has good sound absorption and noise reduction effect, is safe and environmentally friendly, and has good resilience. However, the weather resistance and mechanical properties of the material still need to be further improved, and the sound absorption effect still needs to be further improved.

[0005] It can be seen that developing a preparation method for a composite sound-absorbing material for RVs with good weather resistance and mechanical properties and significant sound absorption effect meets market demand, has broad market value and application prospects, and is of great significance to promoting the development of the field of RV sound-absorbing materials. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a method for preparing a composite sound-absorbing material for RVs which has good weather resistance and mechanical properties and significant sound-absorbing effect.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing a composite sound-absorbing material for a recreational vehicle comprises the following steps:

[0009] Step S1, preparation of functional polymer: 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl and catalyst are added to a high boiling point solvent, stirred and reacted at 68-88° C. for 4-6 hours in an inert gas atmosphere, then heated to 90-95° C. and continued to stir and react for 9-12 hours, precipitated in water after the reaction, washed with ethanol for 3-6 times, and finally rotary evaporated to remove the residual solvent to obtain a functional polymer;

[0010] Step S2, modification of graphene sponge: uniformly dispersing the graphene sponge in N,N-dimethylformamide, then adding silane coupling agent KH560 and melamine thereto, stirring and reacting at 60-80° C. for 3-5 hours, after the reaction is completed, filtering, washing with ethanol 3-6 times, and finally drying in a vacuum drying oven at 85-95° C. to constant weight to obtain a modified graphene sponge;

[0011] Step S3, preparation of functional fibers: adding the functional polymer prepared in step S1, the modified graphene sponge prepared in step S2, and the foaming agent, and chopping and mixing them uniformly to form a mixture; putting the mixture into a twin-screw extruder, and after being ejected through a spinneret, forming a melt-blown ultrafine fiber flow in a hot air drawing system to form functional fibers;

[0012] Step S4, surface modification: tri(2-acryloxyethyl)isocyanurate is added to methanol, and the modified solution is obtained after being evenly dispersed, and the functional fiber is immersed in the modified solution for 10-20 minutes, taken out and subjected to radiation modification under an electron beam, and then dried at 85-95° C. to constant weight, and then washed with ethanol, and dried to obtain the surface-modified functional fiber;

[0013] Step S5, preparation of composite sound-absorbing material: the surface-modified functional fibers are formed into a mesh structure on a centrifugal cotton mesh surface along with a high-speed hot air flow, and then the composite sound-absorbing material is obtained by embossing, winding, cutting and punching in sequence.

[0014] Preferably, the molar ratio of the 2,3,5,6-tetrafluorophenylenediol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, catalyst and high boiling point solvent is 0.7:0.3:1:(0.8-1.2):(9-15).

[0015] Preferably, the catalyst is dibutyltin dilaurate.

[0016] Preferably, the inert gas is any one of nitrogen, helium, neon and argon.

[0017] Preferably, the high boiling point solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone.

[0018] Preferably, the mass ratio of the graphene sponge, N,N-dimethylformamide, silane coupling agent KH560 and melamine in step S2 is 1:(3-5):(0.08-0.12):0.1.

[0019] Preferably, there is no special requirement for the source of the graphene sponge. In one embodiment of the present invention, the graphene sponge is made according to the method of Example 1 of the Chinese invention patent with authorization announcement number CN104291329B.

[0020] Preferably, the mass ratio of the functional polymer in step S3, the modified graphene sponge prepared in step S2, and the foaming agent is (8-12):(55-62):(1-3).

[0021] Preferably, the foaming agent is azodicarbonamide.

[0022] Preferably, the temperature of the spinneret in step S3 is 190°C-210°C.

[0023] Preferably, the mass ratio of tris(2-acryloyloxyethyl)isocyanurate to methanol in step S4 is 0.3:(3-5).

[0024] Preferably, the radiation modification is continuous electron beam radiation, and during the radiation process, the beam current is 30-100 mA, the voltage is 300-600 kV, the radiation dose rate is 10 kGy / h-80 kGy / h, and the absorbed dose is 50 kGy-240 kGy.

[0025] The beneficial effects of adopting the above technical solution are:

[0026] (1) The method for preparing the composite sound-absorbing material for RVs provided by the present invention has a relatively short process flow, convenient operation and control, high preparation efficiency and finished product qualification rate, is suitable for continuous large-scale production, and has a high value for promotion and application.

[0027] (2) The composite sound-absorbing material for RVs provided by the present invention comprises functional polymers, modified graphene sponges and other raw materials; through the mutual coordination and joint action of these raw materials, the sound-absorbing material has good weather resistance and mechanical properties and significant sound absorption effect; the functional polymer is prepared by polycondensation reaction of 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile and 4,4'-diisocyanato-3,3'-dimethylbiphenyl; tetrafluorobenzene, benzo[d]thiazole-2-carbonitrile, biphenyl and polyurethane structures are simultaneously introduced into the molecular chain of the functional polymer; these structures make the weather resistance and mechanical properties of the sound-absorbing material better under the multiple effects of electronic effect, steric effect and conjugation effect; by adding a foaming agent for foaming, in combination with the above structure, the sound absorption effect can be further improved.

[0028] (3) The composite sound-absorbing material for RVs provided by the present invention introduces a melamine structure on the surface of the graphene sponge through modification, which can not only improve the compatibility of the graphene sponge with the substrate, but also can be combined with other raw materials to improve the mechanical properties, sound absorption effect and weather resistance; the functional fiber is irradiated with tri(2-acryloyloxyethyl)isocyanurate to introduce an interpenetrating network cross-linking structure, which can effectively improve the above properties and thus extend its service life. DETAILED DESCRIPTION

[0029] In order to make the technical solution of the present invention better understood by the technical personnel in the field, and to make the above-mentioned features, purposes and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the embodiments. The embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0030] Example 1

[0031] A method for preparing a composite sound-absorbing material for a recreational vehicle comprises the following steps:

[0032] Step S1, preparation of functional polymer: 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl and catalyst were added to a high boiling point solvent, stirred and reacted at 68°C for 4 hours in an inert gas atmosphere, then heated to 90°C and stirred and reacted for 9 hours. After the reaction was completed, the polymer was precipitated in water, washed with ethanol for 3 times, and the residual solvent was removed by rotary evaporation to obtain a functional polymer. The polymer comprises 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, catalyst and high boiling point solvent in a molar ratio of 0.7:0.3:1:0.8:9; the catalyst is dibutyltin dilaurate; the inert gas is nitrogen; the high boiling point solvent is dimethyl sulfoxide; the number average molecular weight of the polymer is 17930 g / mol as measured by GPC, and M W / M n =1.271; through elemental analysis and weight change calculation, the molar ratio of the structural units introduced by 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, and 4,4'-diisocyanato-3,3'-dimethylbiphenyl is the same as the theoretical value;

[0033] Step S2, modification of graphene sponge: uniformly dispersing the graphene sponge in N,N-dimethylformamide, then adding silane coupling agent KH560 and melamine thereto, stirring and reacting at 60° C. for 3 h, after the reaction is completed, filtering, washing with ethanol 3 times, and finally drying in a vacuum drying oven at 85° C. to constant weight to obtain a modified graphene sponge;

[0034] Step S3, preparation of functional fibers: adding the functional polymer prepared in step S1, the modified graphene sponge prepared in step S2, and the foaming agent, and chopping and mixing them uniformly to form a mixture; putting the mixture into a twin-screw extruder, and after being ejected through a spinneret, forming a melt-blown ultrafine fiber flow in a hot air drawing system to form functional fibers;

[0035] Step S4, surface modification: tri(2-acryloxyethyl)isocyanurate is added to methanol, and the modified solution is obtained after being evenly dispersed. The functional fiber is immersed in the modified solution for 10 minutes, taken out and subjected to radiation modification under an electron beam, and then dried at 85° C. to constant weight, and then washed with ethanol, and dried to obtain the surface-modified functional fiber;

[0036] Step S5, preparation of composite sound-absorbing material: the surface-modified functional fibers are formed into a mesh structure on a centrifugal cotton mesh surface along with a high-speed hot air flow, and then the composite sound-absorbing material is obtained by embossing, winding, cutting and punching in sequence.

[0037] The mass ratio of the graphene sponge, N,N-dimethylformamide, silane coupling agent KH560 and melamine in step S2 is 1:3:0.08:0.1; the graphene sponge is made according to the method of Example 1 of the Chinese invention patent with authorization announcement number CN104291329B.

[0038] The mass ratio of the functional polymer, the modified graphene sponge prepared in step S2, and the foaming agent in step S3 is 8:55:1; the foaming agent is azodicarbonamide; the temperature of the spinneret in step S3 is 190°C; the mass ratio of tri(2-acryloxyethyl)isocyanurate and methanol in step S4 is 0.3:3; the radiation modification is continuous electron beam radiation, and during the radiation process, the beam current is 30mA, the voltage is 300kV, the radiation dose rate is 10kGy / h, and the absorbed dose is 50kGy.

[0039] Example 2

[0040] A method for preparing a composite sound-absorbing material for a recreational vehicle comprises the following steps:

[0041] Step S1, preparation of functional polymer: 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl and catalyst are added to a high boiling point solvent, stirred and reacted at 73° C. for 4.5 hours in an inert gas atmosphere, then heated to 92° C. and continued to stir and react for 10 hours, precipitated in water after the reaction, washed with ethanol 4 times, and finally rotary evaporated to remove the residual solvent to obtain a functional polymer;

[0042] Step S2, modification of graphene sponge: uniformly disperse the graphene sponge in N,N-dimethylformamide, then add silane coupling agent KH560 and melamine thereto, stir and react at 65° C. for 3.5 h, after the reaction is completed, filter, wash with ethanol 4 times, and finally place in a vacuum drying oven at 87° C. to dry to constant weight to obtain a modified graphene sponge;

[0043] Step S3, preparation of functional fibers: adding the functional polymer prepared in step S1, the modified graphene sponge prepared in step S2, and the foaming agent, and chopping and mixing them uniformly to form a mixture; putting the mixture into a twin-screw extruder, and after being ejected through a spinneret, forming a melt-blown ultrafine fiber flow in a hot air drawing system to form functional fibers;

[0044] Step S4, surface modification: tri(2-acryloxyethyl)isocyanurate is added to methanol, and the modified solution is obtained after being evenly dispersed. The functional fiber is immersed in the modified solution for 13 minutes, taken out and subjected to radiation modification under an electron beam, and then dried at 87° C. to constant weight, and then washed with ethanol, and dried to obtain the surface-modified functional fiber;

[0045] Step S5, preparation of composite sound-absorbing material: the surface-modified functional fibers are formed into a mesh structure on a centrifugal cotton mesh surface along with a high-speed hot air flow, and then the composite sound-absorbing material is obtained by embossing, winding, cutting and punching in sequence.

[0046] The molar ratio of the 2,3,5,6-tetrafluorophenylenediol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, catalyst and high boiling point solvent is 0.7:0.3:1:0.9:11; the catalyst is dibutyltin dilaurate; the inert gas is helium; and the high boiling point solvent is N,N-dimethylformamide.

[0047] The mass ratio of the graphene sponge, N,N-dimethylformamide, silane coupling agent KH560, and melamine in step S2 is 1:3.5:0.09:0.1; the graphene sponge is made according to the method of Example 1 of the Chinese invention patent with authorization announcement number CN104291329B; the mass ratio of the functional polymer, the modified graphene sponge prepared in step S2, and the foaming agent in step S3 is 9:57:1.5; the foaming agent is azodicarbonamide; the temperature of the spinneret sprayed in step S3 is 195°C.

[0048] The mass ratio of tri(2-acryloyloxyethyl)isocyanurate to methanol in step S4 is 0.3:3.5; the radiation modification is continuous electron beam radiation, during which the beam current is 50 mA, the voltage is 400 kV, the radiation dose rate is 30 kGy / h, and the absorbed dose is 80 kGy.

[0049] Example 3

[0050] A method for preparing a composite sound-absorbing material for a recreational vehicle comprises the following steps:

[0051] Step S1, preparation of functional polymer: 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl and a catalyst are added to a high boiling point solvent, stirred and reacted at 78° C. for 5 hours in an inert gas atmosphere, then heated to 93° C. and continued to stir and react for 11 hours, precipitated in water after the reaction, washed with ethanol 5 times, and finally rotary evaporated to remove the residual solvent to obtain a functional polymer;

[0052] Step S2, modification of graphene sponge: uniformly dispersing the graphene sponge in N,N-dimethylformamide, then adding silane coupling agent KH560 and melamine thereto, stirring and reacting at 70° C. for 4 h, after the reaction is completed, filtering, washing with ethanol 5 times, and finally drying in a vacuum drying oven at 90° C. to constant weight to obtain a modified graphene sponge;

[0053] Step S3, preparation of functional fibers: adding the functional polymer prepared in step S1, the modified graphene sponge prepared in step S2, and the foaming agent, and chopping and mixing them uniformly to form a mixture; putting the mixture into a twin-screw extruder, and after being ejected through a spinneret, forming a melt-blown ultrafine fiber flow in a hot air drawing system to form functional fibers;

[0054] Step S4, surface modification: tri(2-acryloxyethyl)isocyanurate is added to methanol, and the modified solution is obtained after being evenly dispersed. The functional fiber is immersed in the modified solution for 15 minutes, taken out and subjected to radiation modification under an electron beam, then dried at 90° C. to constant weight, washed with ethanol, and dried to obtain a surface-modified functional fiber;

[0055] Step S5, preparation of composite sound-absorbing material: the surface-modified functional fibers are formed into a mesh structure on a centrifugal cotton mesh surface along with a high-speed hot air flow, and then the composite sound-absorbing material is obtained by embossing, winding, cutting and punching in sequence.

[0056] The molar ratio of the 2,3,5,6-tetrafluorophenylenediol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, catalyst and high boiling point solvent is 0.7:0.3:1:1:13; the catalyst is dibutyltin dilaurate; the inert gas is neon; and the high boiling point solvent is N,N-dimethylformamide.

[0057] The mass ratio of the graphene sponge, N,N-dimethylformamide, silane coupling agent KH560, and melamine in step S2 is 1:4:0.1:0.1; the graphene sponge is made according to the method of Example 1 of the Chinese invention patent with authorization announcement number CN104291329B; the mass ratio of the functional polymer, the modified graphene sponge prepared in step S2, and the foaming agent in step S3 is 10:59:2; the foaming agent is azodicarbonamide.

[0058] The temperature of the spinneret in step S3 is 200° C.; the mass ratio of tri(2-acryloxyethyl)isocyanurate to methanol in step S4 is 0.3:4; the radiation modification is continuous electron beam radiation, and during the radiation process, the beam current is 70 mA, the voltage is 450 kV, the radiation dose rate is 50 kGy / h, and the absorbed dose is 150 kGy.

[0059] Example 4

[0060] A method for preparing a composite sound-absorbing material for a recreational vehicle comprises the following steps:

[0061] Step S1, preparation of functional polymer: 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl and a catalyst are added to a high boiling point solvent, stirred and reacted at 85° C. for 5.5 hours in an inert gas atmosphere, then heated to 94° C. and continued to stir and react for 11 hours, precipitated in water after the reaction, washed with ethanol 5 times, and finally rotary evaporated to remove the residual solvent to obtain a functional polymer;

[0062] Step S2, modification of graphene sponge: uniformly disperse the graphene sponge in N,N-dimethylformamide, then add silane coupling agent KH560 and melamine thereto, stir and react at 75°C for 4.5h, after the reaction is completed, filter, wash with ethanol 5 times, and finally place in a vacuum drying oven at 93°C to dry to constant weight to obtain a modified graphene sponge;

[0063] Step S3, preparation of functional fibers: adding the functional polymer prepared in step S1, the modified graphene sponge prepared in step S2, and the foaming agent, and chopping and mixing them uniformly to form a mixture; putting the mixture into a twin-screw extruder, and after being ejected through a spinneret, forming a melt-blown ultrafine fiber flow in a hot air drawing system to form functional fibers;

[0064] Step S4, surface modification: tri(2-acryloxyethyl)isocyanurate is added to methanol, and the modified solution is obtained after being evenly dispersed. The functional fiber is immersed in the modified solution for 18 minutes, taken out and subjected to radiation modification under an electron beam, then dried at 93° C. to constant weight, and then washed with ethanol. After drying, the surface-modified functional fiber is obtained;

[0065] Step S5, preparation of composite sound-absorbing material: the surface-modified functional fibers are formed into a mesh structure on a centrifugal cotton mesh surface along with a high-speed hot air flow, and then the composite sound-absorbing material is obtained by embossing, winding, cutting and punching in sequence.

[0066] The molar ratio of the 2,3,5,6-tetrafluorophenylenediol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, catalyst and high boiling point solvent is 0.7:0.3:1:1.1:14; the catalyst is dibutyltin dilaurate; the inert gas is argon; the high boiling point solvent is a mixture of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone in a mass ratio of 1:2:3.

[0067] The mass ratio of the graphene sponge, N,N-dimethylformamide, silane coupling agent KH560, and melamine in step S2 is 1:4.5:0.11:0.1; the graphene sponge is made according to the method of Example 1 of the Chinese invention patent with authorization announcement number CN104291329B; the mass ratio of the functional polymer, the modified graphene sponge prepared in step S2, and the foaming agent in step S3 is 11:61:2.5; the foaming agent is azodicarbonamide; the temperature of the spinneret sprayed in step S3 is 205°C.

[0068] The mass ratio of tri(2-acryloyloxyethyl)isocyanurate to methanol in step S4 is 0.3:4.5; the radiation modification is continuous electron beam radiation, during which the beam current is 90 mA, the voltage is 550 kV, the radiation dose rate is 70 kGy / h, and the absorbed dose is 220 kGy.

[0069] Example 5

[0070] A method for preparing a composite sound-absorbing material for a recreational vehicle comprises the following steps:

[0071] Step S1, preparation of functional polymer: 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl and a catalyst are added to a high boiling point solvent, stirred and reacted at 88° C. for 6 hours in an inert gas atmosphere, then heated to 95° C. and continued to stir and react for 12 hours, precipitated in water after the reaction, washed with ethanol 6 times, and finally rotary evaporated to remove the residual solvent to obtain a functional polymer;

[0072] Step S2, modification of graphene sponge: uniformly dispersing the graphene sponge in N,N-dimethylformamide, then adding silane coupling agent KH560 and melamine thereto, stirring and reacting at 80° C. for 5 h, after the reaction is completed, filtering, washing with ethanol 6 times, and finally drying in a vacuum drying oven at 95° C. to constant weight to obtain a modified graphene sponge;

[0073] Step S3, preparation of functional fibers: adding the functional polymer prepared in step S1, the modified graphene sponge prepared in step S2, and the foaming agent, and chopping and mixing them uniformly to form a mixture; putting the mixture into a twin-screw extruder, and after being ejected through a spinneret, forming a melt-blown ultrafine fiber flow in a hot air drawing system to form functional fibers;

[0074] Step S4, surface modification: adding tri(2-acryloxyethyl)isocyanurate to methanol, dispersing evenly to obtain a modification solution, soaking the functional fiber in the modification solution for 20 minutes, taking it out and performing radiation modification under an electron beam, then drying it at 95° C. to constant weight, washing it with ethanol, and drying it to obtain a surface-modified functional fiber;

[0075] Step S5, preparation of composite sound-absorbing material: the surface-modified functional fibers are formed into a mesh structure on a centrifugal cotton mesh surface along with a high-speed hot air flow, and then the composite sound-absorbing material is obtained by embossing, winding, cutting and punching in sequence.

[0076] The molar ratio of the 2,3,5,6-tetrafluorophenylenediol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, catalyst and high boiling point solvent is 0.7:0.3:1:1.2:15; the catalyst is dibutyltin dilaurate; the inert gas is argon; the high boiling point solvent is dimethyl sulfoxide; the mass ratio of the graphene sponge, N,N-dimethylformamide, silane coupling agent KH560 and melamine in step S2 is 1:5:0.12:0.1; the graphene sponge is made according to the method of Example 1 of the Chinese invention patent with authorization announcement number CN104291329B; the mass ratio of the functional polymer, the modified graphene sponge made in step S2 and the foaming agent in step S3 is 12:62:3; the foaming agent is azodicarbonamide.

[0077] The temperature of the spinneret in step S3 is 210° C.; the mass ratio of tri(2-acryloxyethyl)isocyanurate to methanol in step S4 is 0.3:5; the radiation modification is continuous electron beam radiation, and during the radiation process, the beam current is 100 mA, the voltage is 600 kV, the radiation dose rate is 80 kGy / h, and the absorbed dose is 240 kGy.

[0078] Comparative Example 1

[0079] A method for preparing a composite sound-absorbing material for a recreational vehicle is substantially the same as that of Example 1, except that an equal amount of 2,3,5,6-tetrafluorophenylenedimethanol is used instead of 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, and a graphene sponge is used instead of a modified graphene sponge.

[0080] Comparative Example 2

[0081] A method for preparing a composite sound-absorbing material for a recreational vehicle is substantially the same as that of Example 1, except that an equal amount of 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile is used instead of 2,3,5,6-tetrafluorophenylenediol, and the functional fiber has no surface modification step.

[0082] The composite sound-absorbing material prepared by the preparation method of the composite sound-absorbing material for RVs described in Examples 1-5 and Comparative Examples 1-2 was subjected to performance tests. The test results are shown in Table 1. The test method is as follows:

[0083] (1) Mechanical properties: According to the nonwoven fabric breaking strength test standard FZ / T60005-1991, the transverse dry breaking strength was tested using a YG028 universal strength tester.

[0084] (2) Sound absorption performance: The average sound absorption coefficient of different samples at 100-5000 Hz was measured using the standing wave tube method.

[0085] (3) Weather resistance: Each product was placed in an environment of 85°C, 85% RH for 200 h. After cooling to room temperature, the dry breaking strength test was performed again according to the method in (1). The retention rate of the dry breaking strength was statistically calculated. The larger the value, the better the weather resistance.

[0086] Table 1

[0087] Test items Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Average sound absorption coefficient (%) 0.88 0.91 0.93 0.94 0.96 0.79 0.84 Breaking strength(N) 56 60 68 73 75 50 45 Weather resistance (%) 99.67 99.78 99.90 99.95 99.98 98.3 97.5

[0088] It can be seen from Table 1 that the composite sound-absorbing material for RVs disclosed in the embodiment of the present invention has better sound absorption effect, mechanical properties and weather resistance than the comparative example; the combined use of 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, modified graphene sponge and surface-modified functional fiber is beneficial to improving the above properties.

[0089] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a composite sound-absorbing material for a motorhome, characterized in that: The steps include: Step S1, preparation of functional polymer: 2,3,5,6-tetrafluorophenylenedimethanol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl and catalyst are added to a high boiling point solvent, stirred and reacted at 68-88° C. for 4-6 hours in an inert gas atmosphere, then heated to 90-95° C. and continued to stir and react for 9-12 hours, precipitated in water after the reaction, washed with ethanol for 3-6 times, and finally rotary evaporated to remove the residual solvent to obtain a functional polymer; Step S2, modification of graphene sponge: uniformly dispersing the graphene sponge in N,N-dimethylformamide, then adding silane coupling agent KH560 and melamine thereto, stirring and reacting at 60-80° C. for 3-5 hours, after the reaction is completed, filtering, washing with ethanol 3-6 times, and finally drying in a vacuum drying oven at 85-95° C. to constant weight to obtain a modified graphene sponge; Step S3, preparation of functional fibers: adding the functional polymer prepared in step S1, the modified graphene sponge prepared in step S2, and the foaming agent, and chopping and mixing them uniformly to form a mixture; putting the mixture into a twin-screw extruder, and after being ejected through a spinneret, forming a melt-blown ultrafine fiber flow in a hot air drawing system to form functional fibers; Step S4, surface modification: tri(2-acryloxyethyl)isocyanurate is added to methanol, and the modified solution is obtained after being evenly dispersed, and the functional fiber is immersed in the modified solution for 10-20 minutes, taken out and subjected to radiation modification under an electron beam, and then dried at 85-95° C. to constant weight, and then washed with ethanol, and dried to obtain the surface-modified functional fiber; Step S5, preparation of composite sound-absorbing material: the surface-modified functional fibers are formed into a mesh structure on a centrifugal cotton mesh surface along with a high-speed hot air flow, and then the composite sound-absorbing material is obtained by embossing, winding, cutting and punching in sequence.

2. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The molar ratio of the 2,3,5,6-tetrafluorophenylenediol, 4,6-dihydroxybenzo[d]thiazole-2-carbonitrile, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, catalyst and high boiling point solvent is 0.7:0.3:1:(0.8-1.2):(9-15).

3. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate.

4. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The inert gas is any one of nitrogen, helium, neon and argon.

5. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The high boiling point solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone.

6. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The mass ratio of the graphene sponge, N,N-dimethylformamide, silane coupling agent KH560 and melamine in step S2 is 1:(3-5):(0.08-0.12):0.

1.

7. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The mass ratio of the functional polymer in step S3, the modified graphene sponge prepared in step S2, and the foaming agent is (8-12):(55-62):(1-3).

8. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The foaming agent is azodicarbonamide.

9. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The temperature of the spinneret in step S3 is 190° C.-210° C.; the mass ratio of tris(2-acryloyloxyethyl)isocyanurate to methanol in step S4 is 0.3:(3-5).

10. The method for preparing the composite sound-absorbing material for RV according to claim 1, characterized in that: The radiation modification is continuous electron beam radiation. During the radiation process, the beam current is 30-100 mA, the voltage is 300-600 kV, the radiation dose rate is 10 kGy / h-80 kGy / h, and the absorbed dose is 50 kGy-240 kGy.