CN111087618B

CN111087618B - Sound absorption and noise reduction type polyimide foam, sound absorption and noise reduction type high-speed train cold-proof material and application

Info

Publication number: CN111087618B
Application number: CN201911403308.XA
Authority: CN
Inventors: 周光远; 聂赫然; 周鹤; 黄志成; 顾铭茜
Original assignee: Jiangsu Zhongke Polymer New Material Industry Technology Research Institute Co ltd
Current assignee: Changzhou Fulong New Technology Materials Co ltd
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2022-10-14
Anticipated expiration: 2039-12-30
Also published as: CN111087618A

Abstract

The invention provides a sound absorption and noise reduction type polyimide foam material, which comprises the following raw materials of 15-63 parts by weight of isocyanate, 19-66 parts by weight of aromatic dianhydride, 15-41 parts by weight of solvent, 0.1-25 parts by weight of foaming agent, 2-14 parts by weight of foam homogenizing agent, 0.1-8.5 parts by weight of catalyst, 1-20 parts by weight of flame retardant, 5-35 parts by weight of hollow glass microsphere and 5-30 parts by weight of coupling agent. According to the invention, hollow glass beads are added to form cavity resonance, the material is softened, and the noise-reducing wedge structure is introduced to improve the matching degree of the acoustic impedance of the material and the acoustic impedance of air, so that the sound absorption and noise reduction performance of the polyimide foam cold-proof material for high-speed rails is improved, a technical basis is laid for the preparation of the high-performance heat-insulation and sound-absorption integrated functional cold-proof material, the preparation process flow is simple, the loading is convenient and fast, and a new idea is provided for improving the sound absorption performance of the high-speed rail cold-proof material.

Description

Sound absorption and noise reduction type polyimide foam, sound absorption and noise reduction type high-speed train cold-proof material and application

Technical Field

The invention belongs to the technical field of heat-insulating cold-proof materials, relates to sound-absorbing noise-reducing polyimide foam, a sound-absorbing noise-reducing cold-proof material and application, and particularly relates to sound-absorbing noise-reducing polyimide foam, a sound-absorbing noise-reducing high-speed train cold-proof material and application.

Background

In the current high-speed and high-efficiency society, more convenient and faster traffic development is required, various motion carriers (traffic tools) are designed with light weight and heat insulation for energy conservation, environmental protection and high speed, for example, most aviation materials have the advantages of low density, high strength, no expansion and contraction, no metal fatigue, flame retardance, no toxicity, low temperature resistance and the like, and in recent years, along with the vigorous development of the high-speed railway industry in China, the design and performance requirements of high-speed trains are continuously developed and improved, and are increasingly strict. The running speed, the service life and the selected materials of the high-speed train are all important factors directly related to the riding comfort, the safety and the reliability of the train during running. The high-speed rail provides a quick, punctual, convenient, safe and comfortable public transportation mode for the public, establishes and improves the traffic condition, the investment environment, the ecological environment and the urban environment, improves the life quality of people, and brings great influence to passengers in the vehicle, track residents and passengers on the coming vehicle during meeting.

Polyimide foam has the characteristics of sound absorption and noise reduction, heat preservation and heat insulation and safe fire prevention, and the bending, the compressibility is good, can guarantee that steel, wooden structure room installation is closely knit, do not leave the clearance, can cut thickness and length and width size according to actual demand simultaneously, and easily fix, be the excellent selection as high-speed railway winter protection material, as the necessity, almost covered every corner of carriage, be applied to it in train back wall, ceiling system, wind channel, tuber pipe, door or partition wall, compare other traditional material quality lighter, the energy efficiency of rail train has been improved. Therefore, the polyimide foam has obvious advantages when being used as a cold-proof material for high-speed rail trains such as high-speed rails, motor trains, subways and light rails.

However, although the polyimide foam cold-proof material has more outstanding heat-insulating property compared with the traditional cold-proof material, the sound absorption and noise reduction performance of the polyimide foam has a larger difference compared with polymer-based porous sound absorption materials such as polyurethane foam and melamine foam. The prior art CN101402743 discloses a polyimide foam and a preparation method thereof, the octave average sound absorption coefficient of the polyimide foam material prepared in the patent is between 0.38 and 0.5, while the average sound absorption coefficients of polyurethane foam and melamine foam are between 0.6 and 0.8, which still has a large gap, how to make the polyimide foam cold-proof material play a great role in heat insulation and heat preservation, enhance the sound absorption and noise reduction performance thereof, and effectively block the propagation of noise, which is a problem to be solved urgently.

Therefore, the polyimide foam cold-proof material with excellent sound absorption and noise reduction performance is provided to solve the problems in the prior art, has great significance and prospect for the development and application of the high-speed rail train industry, and is one of the focuses of domestic high-speed train material production enterprises and first-line researchers.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a sound absorption and noise reduction type polyimide foam, a sound absorption and noise reduction type cold-proof material, and an application thereof, in particular, a sound absorption and noise reduction type polyimide foam. The polyimide foam provided by the invention can be combined with a subsequent material softening process and a structure introduced with a silencing wedge by adding hollow glass beads to form cavity resonance, the matching degree of the acoustic impedance of the material and the acoustic impedance of air is improved, the sound absorption and noise reduction performance of the polyimide foam cold-proof material for high-speed rails is improved, a technical foundation is laid for the preparation of the high-performance heat-insulation and sound-absorption integrated functional cold-proof material, and meanwhile, the polyimide foam is safe, environment-friendly and convenient to pave, and is favorable for application and popularization in the manufacturing industry of high-speed rail trains.

The invention provides a sound absorption and noise reduction type polyimide foam material which comprises the following raw materials in percentage by mass:

preferably, the diameter of the hollow glass bead is 15-50 μm;

the isocyanate comprises one or more of polyphenyl polymethylene polyisocyanate, 4' -diphenylmethane diisocyanate, 2, 6-toluene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate;

the aromatic dianhydride comprises pyromellitic dianhydride, 3', 4' -benzophenone tetracarboxylic dianhydride, 3', 4' -biphenyl tetracarboxylic dianhydride and 3,3', one or more of 4,4' -diphenyl ether tetracarboxylic dianhydride and 3,3', 4' -biphenyl sulfone tetracarboxylic dianhydride;

the solvent comprises one or more of N, N '-dimethylformamide, N' -dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide;

the foaming agent comprises one or more of water, methanol, ethanol, ethylene glycol monobutyl ether, n-pentane, acetone and tetrahydrofuran.

Preferably, the foam stabilizer comprises one or more of polyether modified silicone oil, silicone glycol copolymer, polyether modified siloxane, water-soluble silicone oil and silicone polyether copolymer surfactant;

the catalyst comprises a metal catalyst and/or an amine catalyst;

the coupling agent comprises one or more of silane coupling agent, titanate coupling agent, metal coupling agent and lignin coupling agent;

the flame retardant comprises one or more of diethylene glycol bis (2-chloroethyl) phosphate, tri (polyoxyalkylene) phosphite, tri (2-chloroethyl) phosphate and ethyl diethyl phosphate;

the polyimide foam material comprises a polyimide foam material subjected to pressure softening treatment.

The invention provides a preparation method of sound absorption and noise reduction type polyimide foam material, which comprises the following steps:

1) Premixing a solvent, aromatic dianhydride and a flame retardant to obtain a mixture A;

primarily mixing hollow glass beads, a catalyst, a foaming agent, a foam stabilizer and a coupling agent to obtain a mixture B;

2) And stirring and degassing the isocyanate, the mixture A and the mixture B respectively, then injecting the mixture into a mould for foaming after closed high-speed mixing, and obtaining the sound absorption and noise reduction type polyimide foam material after molding and curing.

Preferably, the hollow glass beads are vacuum dehydrated hollow glass beads;

the temperature of the premixing is 5-40 ℃;

the pre-mixing time is 1-2 h;

the pre-mixing rotating speed is 1000-3000 rpm;

the temperature of the primary mixing is 5-40 ℃;

the time for the primary mixing is 1-2 h;

the rotation speed of the primary mixing is 1000-3000 rpm.

Preferably, the temperature of the vacuum dehydration is 180-200 ℃;

the vacuum dehydration time is 3-8 h;

the high-speed mixing time is 0.1-1 min;

the rotating speed of the high-speed mixing is 3000-5000 rpm;

the mould comprises an open foaming mould;

the foaming temperature is 10-40 ℃;

the foaming time is 0.5-2 h.

Preferably, the injection speed is 3-20L/min;

the molding and curing time is 3-8 h;

the temperature for molding and curing is 150-280 ℃;

the step of pressurizing and softening treatment is also included after the molding and curing;

the pressure of the pressure softening treatment is 0.1-10 MPa;

the temperature of the pressure softening treatment is 10-200 ℃;

the time of the pressure softening treatment is 1-30 min.

The invention provides a sound absorption and noise reduction type cold-proof material which is made of the sound absorption and noise reduction type polyimide foam material prepared by the preparation method in any one of the technical schemes or the sound absorption and noise reduction type polyimide foam material prepared by the preparation method in any one of the technical schemes;

the cold-proof material has a three-wedge structure.

Preferably, the wedge height of the cold-proof material is 5-8 cm;

the interval between the adjacent tips of the wedges of the cold-proof material is 1-2 cm;

the sound absorption and noise reduction type polyimide foam material is provided with complete and/or incomplete hollow glass beads on the surface;

the cold-proof material also comprises an environment-friendly adhesive compounded on the sound-absorption noise-reduction type polyimide foam material;

the environment-friendly adhesive comprises one or more of a UV curing adhesive, a high solid content adhesive and a biodegradable adhesive.

The invention also provides the sound absorption and noise reduction type polyimide foam material prepared by the preparation method of any one of the above technical schemes, or the application of the sound absorption and noise reduction type cold-proof material of any one of the above technical schemes in the aspect of vehicles or rail transit.

The invention provides a sound-absorbing noise-reducing polyimide foam material, which comprises the following raw materials of 15-63 parts by weight of isocyanate, 19-66 parts by weight of aromatic dianhydride, 15-41 parts by weight of solvent, 0.1-25 parts by weight of foaming agent, 2-14 parts by weight of foam homogenizing agent, 0.1-8.5 parts by weight of catalyst, 1-20 parts by weight of flame retardant, 5-35 parts by weight of hollow glass beads and 5-30 parts by weight of coupling agent. Compared with the prior art, the invention aims at the problem of poor sound absorption and noise reduction performance of the existing polyimide foam. According to the invention, the hollow glass beads are creatively added into the polyimide foam material, after sound waves enter the foam, the propagation path of the sound waves is prolonged, and meanwhile, the absorption of the sound waves is increased due to the cavity resonance effect of the hollow glass beads, so that the sound absorption and noise reduction performance of the polyimide foam material is improved. After the sound waves are incident, the sound waves and the hollow glass beads generate certain interaction, so that the propagation path of the sound waves in the polyimide foam cold-proof material is prolonged, and the attenuation performance of the material to the sound waves is enhanced; on the other hand, according to the sound absorption principle of the material, the hollow glass beads have a cavity resonance sound absorption effect and can generate microphase separation with the cold-proof material matrix, so that the sound absorption performance of the material can be enhanced. In addition, the interaction between the glass beads and the cold-proof material matrix can increase the internal friction of the system, thereby increasing the loss of the material to incident sound energy and improving the sound absorption performance of the material. The wedge is established, so that when noise enters from the tip, the acoustic impedance of the material can be well matched with that of air, and the noise is efficiently absorbed. And the specific hollow glass beads are adopted, so that the strength, rigidity, stability, impact toughness and other characteristics of the polyimide foam cold-proof material can be improved.

According to the sound absorption and noise reduction type cold-proof material, the hollow glass beads are added to form cavity resonance, so that the absorption of sound waves is increased, the material softening and noise reduction wedge structures are combined, the softening process is utilized to enable the cavities in the polyimide foam cold-proof material to be mutually communicated to form a sound absorption structure, and the sound absorption structure is matched with the hollow glass beads, so that sound is continuously refracted, reflected and frictionally heated to be dissipated after entering the holes; the introduction of amortization wedge structure makes the acoustic impedance of material match the acoustic impedance of air better, carries out the high-efficient absorption to sound, has improved polyimide foam material's sound absorption and noise reduction performance greatly, through adjusting wedge length, cavity degree of depth etc. and two preceding combinations of cooperation, can effectively improve the sound absorption characteristic of wedge structure. According to the invention, the hollow glass beads and the material are softened, and the silencing wedge structure is introduced to improve the matching degree of the acoustic impedance of the material and the acoustic impedance of air, so that the sound absorption and noise reduction performance of the polyimide foam cold-proof material for the high-speed rail is improved, a technical foundation is laid for the preparation of the high-performance heat-insulation and sound-absorption integrated functional cold-proof material, the polyimide foam cold-proof material is simple in preparation process flow, the later-stage loading is convenient and rapid, and a new idea is provided for improving the sound absorption performance of the high-speed rail cold-proof material.

Experimental results show that the sound absorption and noise reduction type cold-proof material provided by the invention has excellent sound absorption performance, and the sound absorption coefficient reaches 0.73. The wedge structure and the softening treatment process can further improve the sound absorption and noise reduction performance of the polyimide foam cold-proof material.

Drawings

FIG. 1 is a schematic diagram of a sound-absorbing noise-reducing polyimide foam cold-proof material product structure provided by the present invention.

Detailed Description

For a further understanding of the present invention, the following description of the preferred embodiments of the present invention is given in conjunction with the examples, but it is to be understood that these descriptions are only intended to further illustrate the features and advantages of the present invention, and not to limit the claims of the present invention.

All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.

All the raw materials of the present invention are not particularly limited in their purity, and the present invention preferably employs the purity which is conventional in the field of industrial purity or the production of cold-proof materials.

All the raw materials, the marks and the acronyms thereof belong to the conventional marks and acronyms in the field, each mark and acronym is clear and definite in the field of related application, and the raw materials can be purchased from the market or prepared by a conventional method by the technical staff in the field according to the marks, the acronyms and the corresponding application.

All the processes of the invention, the abbreviations thereof belong to the common abbreviations in the art, each abbreviation is clear and definite in the field of its associated use, and the ordinary process steps thereof can be understood by those skilled in the art from the abbreviations.

The invention provides a sound absorption and noise reduction type polyimide foam material, which comprises the following raw materials:

in the present invention, the parts by weight and the mass percentages are only different in terms of expressions and the same in essential meanings, and those skilled in the art can understand the correct meanings based on the general knowledge and can uniquely determine the same.

The isocyanate of the present invention is added in an amount of 15 to 63 parts by weight, more preferably 20 to 58 parts by weight, more preferably 25 to 53 parts by weight, more preferably 30 to 48 parts by weight, and more preferably 35 to 43 parts by weight. The specific selection and related parameters of the isocyanate are not particularly limited in principle, and can be selected and adjusted by those skilled in the art according to actual production conditions, application requirements and quality control, and the isocyanate preferably includes one or more of polyphenyl polymethylene polyisocyanate, 4 '-diphenylmethane diisocyanate, 2, 6-toluene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate, and more preferably polyphenyl polymethylene polyisocyanate (PAPI), 4' -diphenylmethane diisocyanate (MDI), 2, 6-Toluene Diisocyanate (TDI), isophorone diisocyanate (IPDI) or Hexamethylene Diisocyanate (HDI), so as to better improve the sound absorption and noise reduction properties of the foam, ensure the structure of the material body, and ensure the comprehensive properties of heat insulation and mechanical properties.

The amount of the aromatic dianhydride used in the present invention is 19 to 66 parts by weight, more preferably 24 to 61 parts by weight, still more preferably 29 to 56 parts by weight, still more preferably 34 to 51 parts by weight, and still more preferably 39 to 46 parts by weight. The concrete selection of the aromatic dianhydride is not particularly limited in principle, and the aromatic dianhydride can be selected and adjusted by a person skilled in the art according to the actual production condition, application requirements and quality control, in order to better improve the sound absorption and noise reduction performance of the foam material, ensure the structure of a material main body, ensure the comprehensive performances such as heat insulation performance, mechanical property and the like, preferably comprises pyromellitic dianhydride and 3,3', one or more of 4,4' -benzophenone tetracarboxylic dianhydride, 3', 4' -biphenyl tetracarboxylic dianhydride, 3', 4' -diphenyl ether tetracarboxylic dianhydride and 3,3', 4' -biphenyl sulfone tetracarboxylic dianhydride, more preferably pyromellitic dianhydride (PMDA), 3', 4' -Benzophenone Tetracarboxylic Dianhydride (BTDA), 3', 4' -biphenyl tetracarboxylic dianhydride (BPDA) or 3,3', 4' -diphenyl ether tetracarboxylic dianhydride (ODPA).

The solvent of the present invention is added in an amount of 15 to 41 parts by weight, preferably 20 to 36 parts by weight, and more preferably 25 to 31 parts by weight. The specific choice of the solvent is not particularly limited in the present invention, and those skilled in the art can select and adjust the solvent according to actual production conditions, application requirements and quality control, and the solvent preferably includes one or more of N, N '-dimethylformamide, N' -dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide, and more preferably N, N '-Dimethylformamide (DMF), N' -Dimethylacetamide (DMAC), in order to better improve the sound absorption and noise reduction properties of the foam, ensure the structure of the material body, and ensure the comprehensive properties of heat insulation and mechanical properties. N-methyl-2-pyrrolidone (NMP) or dimethyl sulfoxide (DMSO).

The amount of the blowing agent of the present invention is 0.1 to 25 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight, and still more preferably 5 to 10 parts by weight. The concrete selection of the foaming agent is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual production conditions, application requirements and quality control.

The amount of the foam stabilizer of the present invention is 2 to 14 parts by weight, preferably 4 to 12 parts by weight, and more preferably 6 to 10 parts by weight. The concrete selection of the foaming agent is not particularly limited in principle, and a person skilled in the art can select and adjust the foaming agent according to actual production conditions, application requirements and quality control.

The catalyst of the present invention is added in an amount of 0.1 to 8.5 parts by weight, preferably 0.5 to 7.5 parts by weight, more preferably 1 to 7 parts by weight, more preferably 2 to 6 parts by weight, and more preferably 3 to 5 parts by weight. The invention has no special restriction on the specific selection of the catalyst in principle, and the technicians in the field can select and adjust the catalyst according to the actual production condition, application requirements and quality control, in order to better improve the sound absorption and noise reduction performance of the foam material, ensure the structure of the material main body, ensure the comprehensive performances such as heat insulation performance, mechanical property and the like, the catalyst preferably comprises a metal catalyst and/or an amine catalyst, more preferably a metal catalyst or an amine catalyst, specifically, the solvent may be one or more of dibutyltin dilaurate, stannous isooctanoate, N, N-dimethylcyclohexylamine, bis (2-dimethylaminoethyl) ether, N, N, N ', N' -tetramethylalkylenediamine, triethylamine and N, N-dimethylbenzylamine, or may be one or more of dibutyltin dilaurate, stannous isooctanoate, N, N-dimethylcyclohexylamine, bis (2-dimethylaminoethyl) ether, N, N, N ', N' -tetramethylalkylenediamine, triethylamine or N, N-dimethylbenzylamine.

The flame retardant of the present invention is added in an amount of 1 to 20 parts by weight, preferably 3 to 18 parts by weight, more preferably 5 to 16 parts by weight, more preferably 7 to 14 parts by weight, more preferably 9 to 12 parts by weight. The specific selection of the flame retardant is not particularly limited in principle, and can be selected and adjusted by those skilled in the art according to actual production conditions, application requirements and quality control, and the flame retardant preferably includes one or more of diethylene glycol bis (2-chloroethyl) phosphate, tris (polyoxyalkylene) phosphite, tris (2-chloroethyl) phosphate and ethyl diethyl phosphate, and more preferably diethylene glycol bis (2-chloroethyl) phosphate, tris (polyoxyalkylene) phosphate or tris (polyoxyalkylene) phosphite, in order to better improve the sound absorption and noise reduction performance of the foam, ensure the structure of the material body, and ensure the comprehensive performance of heat insulation performance and mechanical property.

The coupling agent of the present invention is added in an amount of 5 to 30 parts by weight, preferably 10 to 25 parts by weight, more preferably 15 to 20 parts by weight, and still more preferably 5 to 30 parts by weight. The concrete selection of the coupling agent is not particularly limited in principle, and a person skilled in the art can select and adjust the coupling agent according to the actual production condition, application requirements and quality control.

The hollow glass bead of the present invention is added in an amount of 5 to 35 parts by weight, preferably 7 to 33 parts by weight, more preferably 10 to 30 parts by weight, more preferably 12 to 28 parts by weight, more preferably 15 to 25 parts by weight, more preferably 18 to 23 parts by weight. The specific parameters of the hollow glass beads are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual production conditions, application requirements and quality control, and the diameter of the hollow glass beads is particularly preferably 15-50 μm, more preferably 20-45 μm, more preferably 25-40 μm, and more preferably 30-35 μm, so as to better improve the sound absorption and noise reduction performance of the foam material, ensure the structure of the material main body, and ensure the comprehensive performance such as heat insulation performance and mechanical performance.

The invention basically has no special limitation on the specific structure of the sound absorption and noise reduction type polyimide foam material, and technicians in the field can select and adjust the sound absorption and noise reduction type polyimide foam material according to actual production conditions, application requirements and quality control.

The concrete parameters of the three-point split structure are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual production conditions, application requirements and quality control, in order to better improve the sound absorption and noise reduction performance of the foam material, ensure the structure of the material main body and ensure the comprehensive performance such as heat insulation performance, mechanical performance and the like, the height of the split of the three-point split structure is preferably 5-8 cm, more preferably 5.5-7.5 cm, and more preferably 6-7 cm. The interval between adjacent tips of the wedges of the three-wedge structure is preferably 1-2 cm. More preferably 1.2 to 1.8cm, still more preferably 1.4 to 1.6cm.

The invention is a preparation process of the sound absorption and noise reduction type polyimide foam material which is complete and refined, the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material is better improved, the structure of a material main body is ensured, and the comprehensive performances such as heat insulation performance, mechanical property and the like are ensured.

The sound absorption and noise reduction type polyimide foam material provided by the invention is particularly formed by combining hollow glass beads, softening and silencing wedges, so that the sound absorption performance of a cold-proof material is improved, and the performance is further improved by utilizing three comprehensive technologies. The softening process enables the cavities in the polyimide foam cold-proof material to be mutually communicated to form a sound absorption structure, sound is continuously refracted, reflected and subjected to frictional heat generation to be dissipated after entering the cavities, the sound absorption wedge can absorb the sound to the maximum extent, particularly the part of a medium-low frequency wave band, the sound absorption wedge is particularly suitable for high-speed rail bass absorption, the hollow glass beads are added, the internal friction of the system is increased, the sound transmission path is prolonged, and the sound absorption is greatly facilitated.

The invention provides a preparation method of a sound absorption and noise reduction type polyimide foam material, which is characterized by comprising the following steps:

2) And (3) stirring and degassing the isocyanate, the mixture A and the mixture B respectively, then injecting the mixture into a mold for foaming after airtight high-speed mixing, and obtaining the sound-absorbing and noise-reducing polyimide foam material after molding and curing.

In the preparation method of the sound absorption and noise reduction type polyimide foam material, the selection and proportion of the raw materials and the preferred range thereof can preferably correspond to the selection and proportion of the corresponding raw materials in the sound absorption and noise reduction type polyimide foam material and the preferred range thereof one by one, and the details are not repeated herein.

Firstly, premixing a solvent, aromatic dianhydride and a flame retardant to obtain a mixture A; and (3) primarily mixing the hollow glass beads, the catalyst, the foaming agent, the foam stabilizer and the coupling agent to obtain a mixture B.

The specific pre-mixing mode and parameters are not particularly limited in principle, and a person skilled in the art can select and adjust the pre-mixing mode and parameters according to actual production conditions, application requirements and quality control. The temperature of the premixing is preferably normal temperature, more preferably 5 to 40 ℃, even more preferably 10 to 35 ℃, even more preferably 15 to 30 ℃, even more preferably 20 to 25 ℃. The time of the premixing is preferably 1 to 2 hours, more preferably 1.2 to 1.8 hours, and still more preferably 1.4 to 1.6 hours. The pre-mixing rotation speed is preferably 1000 to 3000rpm, more preferably 1200 to 2800rpm, more preferably 1500 to 2500rpm, more preferably 1800 to 2300rpm.

The invention has no special limitation on the processing mode of the hollow glass beads in principle, and a person skilled in the art can select and adjust the hollow glass beads according to the actual production condition, application requirements and quality control.

The specific parameters of the vacuum dehydration are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual production conditions, application requirements and quality control, the temperature of the vacuum dehydration is preferably 180-200 ℃, more preferably 182-198 ℃, more preferably 185-195 ℃, and more preferably 187-193 ℃ to better improve the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material, ensure the structure of the material main body, and ensure the comprehensive performance such as heat insulation performance and mechanical performance. The time for the vacuum dehydration is preferably 3 to 8 hours, more preferably 4 to 7 hours, and still more preferably 5 to 6 hours.

The concrete mode and parameters of the primary mixing are not particularly limited in principle, and a person skilled in the art can select and adjust the mode according to actual production conditions, application requirements and quality control. The temperature of the premixing is preferably normal temperature, more preferably 5 to 40 ℃, even more preferably 10 to 35 ℃, even more preferably 15 to 30 ℃, even more preferably 20 to 25 ℃. The time for the initial mixing is preferably 1 to 2 hours, more preferably 1.2 to 1.8 hours, and still more preferably 1.4 to 1.6 hours. The rotation speed of the initial mixing is preferably 1000 to 3000rpm, more preferably 1200 to 2800rpm, more preferably 1500 to 2500rpm, and more preferably 1800 to 2300rpm.

Finally, stirring and degassing isocyanate, the mixture A and the mixture B respectively, then injecting the mixture into a mould for foaming after closed high-speed mixing, and obtaining the sound absorption and noise reduction type polyimide foam material after molding and curing.

The concrete mode and parameters of the stirring degassing are not particularly limited in principle, and a person skilled in the art can select and adjust the mode according to actual production conditions, application requirements and quality control.

The specific parameters of the closed high-speed mixing are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual production conditions, application requirements and quality control, the time for the closed high-speed mixing is preferably 0.1-1 min, more preferably 0.3-0.8 min, and more preferably 0.5-0.6 min, in order to better improve the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material, ensure the structure of the material main body, and ensure the comprehensive performances such as heat insulation performance, mechanical performance and the like. The rotation speed of the high-speed mixing is preferably 3000 to 5000rpm, more preferably 3200 to 4800rpm, more preferably 3500 to 4500rpm, and more preferably 3700 to 4300rpm.

The specific parameters of the injection are not particularly limited in principle, and a person skilled in the art can select and adjust the parameters according to actual production conditions, application requirements and quality control, the speed of the injection is preferably 3-20L/min, more preferably 5-18L/min, more preferably 8-15L/min, and more preferably 10-13L/min, so as to better improve the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material, ensure the structure of the material main body, and ensure the comprehensive performances such as heat insulation performance and mechanical performance.

The concrete selection of the mold is not particularly limited in principle, and technicians in the field can select and adjust the mold according to actual production conditions, application requirements and quality control, so that the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material is better improved, the structure of a material main body is ensured, and comprehensive performances such as heat insulation performance, mechanical performance and the like are ensured, and the mold preferably comprises an open type foaming mold.

The foaming parameters are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual production conditions, application requirements and quality control, the foaming time is preferably 0.5-2 hours, more preferably 0.8-1.8 hours, and more preferably 1-1.5 hours, in order to better improve the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material, ensure the structure of the material main body, and ensure the comprehensive performance such as heat insulation performance and mechanical performance. The foaming temperature is preferably room temperature, and specifically may be 10 to 40 ℃, more preferably 15 to 35 ℃, and still more preferably 20 to 30 ℃.

The parameters of the forming and curing are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual production conditions, application requirements and quality control, the time of the forming and curing is preferably 3-8 hours, more preferably 4-7 hours, and more preferably 5-6 hours, in order to better improve the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material, ensure the structure of the material main body, and ensure the comprehensive properties such as heat insulation performance and mechanical property. The temperature for the molding and curing is preferably 150 to 280 ℃, more preferably 180 to 250 ℃, and still more preferably 200 to 230 ℃.

The invention is a preparation process of the sound absorption and noise reduction type polyimide foam material which is complete and refined, the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material is better improved, the structure of a material main body is ensured, the comprehensive performances such as heat insulation performance, mechanical property and the like are ensured, and the pressurizing and softening treatment step is preferably further included after the molding and curing.

The specific modes and parameters of the pressure softening treatment are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual production conditions, application requirements and quality control. The pressure for the pressure softening treatment of the present invention is preferably 0.1 to 10MPa, more preferably 2 to 8MPa, and still more preferably 4 to 6MPa. The time for the pressure softening treatment is preferably 1 to 30min, more preferably 5 to 25min, more preferably 10 to 20min, more preferably 12 to 18min, and more preferably 14 to 16min. The temperature of the pressure softening treatment is preferably 10 to 200 ℃, more preferably 30 to 150 ℃, more preferably 40 to 100 ℃, and more preferably 50 to 70 ℃.

The invention relates to a preparation process for a complete and refined sound absorption and noise reduction type polyimide foam material, which can better improve the sound absorption and noise reduction performance of the sound absorption and noise reduction type polyimide foam material, ensure the structure of a material main body, and ensure the comprehensive performances such as heat insulation performance, mechanical property and the like, and the preparation process for the sound absorption and noise reduction type polyimide foam material can specifically comprise the following steps:

the method comprises the following steps: and (4) dehydrating the hollow glass microspheres in vacuum.

Step two: pouring isocyanate into a material tank A;

step three: uniformly stirring the solvent, the aromatic dianhydride and the flame retardant, and pouring into a tank B;

step four: uniformly stirring the hollow glass microspheres, the catalyst, the foam stabilizer and other auxiliaries, and then pouring the mixture into a tank C;

step five: respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials;

step six: precisely controlling the flow rates of the raw materials of the tanks A, B and C by a computer, mixing the raw materials at a high speed through a closed mixing cavity, injecting the mixture into a mold for foaming, and forming and curing to prepare the sound-absorbing noise-reducing polyimide foam material;

step seven: and setting the temperature of a flat plate oil press, primarily cutting the polyimide foam obtained in the step, and then placing the polyimide foam on a press for pressurization. And performing softening treatment to obtain the sound absorption and noise reduction type polyimide foam material after the softening treatment.

The invention particularly selects a softening process to mutually communicate the cavities in the polyimide foam cold-proof material, and combines the hollow glass beads to form a sound absorption structure, so that sound is continuously refracted, reflected and frictionally heated to be dissipated after entering the cavities. And the subsequent introduction of a silencing wedge structure is combined, so that the acoustic impedance of the material is well matched with that of air, sound is efficiently absorbed, and the sound absorption and noise reduction performance of the polyimide foam material is greatly improved.

the cold-proof material has a three-wedge structure.

In the sound absorption and noise reduction type cold-proof material, the selection, structure and preferable range of the sound absorption and noise reduction type polyimide foam material can be in one-to-one correspondence with the selection, structure and preferable range of the polyimide foam material, and the detailed description is omitted.

The invention has no special limitation on the specific parameters of the three-point split structure of the cold-proof material in principle, and the skilled person in the art can select and adjust the three-point split structure according to the actual production condition, application requirements and quality control, in order to better improve the sound absorption and noise reduction performance of the cold-proof material, ensure the structure of the material main body and ensure the comprehensive performances such as heat insulation performance, mechanical performance and the like, the height of the three-point split structure is preferably 5-8 cm, more preferably 5.5-7.5 cm, and more preferably 6-7 cm. The interval between adjacent tips of the wedges of the three-wedge structure of the cold-proof material is preferably 1-2 cm. More preferably 1.2 to 1.8cm, still more preferably 1.4 to 1.6cm.

The sound absorption and noise reduction type polyimide foam material is a complete and refined integral technical scheme, and the surface of the sound absorption and noise reduction type polyimide foam material can have complete and/or incomplete hollow glass beads due to the fact that a three-point split structure is formed by cutting, and more preferably, the complete and incomplete hollow glass beads are randomly arranged. The complete and incomplete hollow glass beads irregularly arranged on the surface of the polyimide foam material can further prolong the propagation path of sound waves, better enhance the attenuation performance of the material to the sound waves, and further enhance the continuous refraction, reflection and frictional heat generation of the sound waves in the material, thereby accelerating the consumption of the sound waves.

The invention relates to a preparation process of a complete and refined sound-absorbing and noise-reducing type polyimide foam material, which can better improve the sound-absorbing and noise-reducing performance of a sound-absorbing and noise-reducing type cold-proof material and ensure the comprehensive performances such as heat-insulating performance, mechanical performance and the like, and the cold-proof material preferably also comprises an environment-friendly adhesive compounded on the sound-absorbing and noise-reducing type polyimide foam material. Specifically, the environment-friendly adhesive preferably comprises one or more of a UV-curable adhesive, a high-solid-content adhesive and a biodegradable adhesive, and more preferably comprises a UV-curable adhesive, a high-solid-content adhesive or a biodegradable adhesive.

The single glass bead adding, wedge structure and softening treatment can improve the sound absorption and noise reduction performance to a certain extent, and the three are combined and matched with each other, so that the sound absorption and noise reduction performance is further improved, and meanwhile, the cold-proof material is bonded with the interior of a carriage, and is applied to high-speed rails, so that the sound absorption and noise reduction performance can be improved, and the reduction of the main parameter heat conductivity coefficient of the cold-proof material is also improved. This is because the polyimide foam winter protection material that passes through softening process can effectively avoid because of the clearance that the construction caused when the loading of later stage, bonds between winter protection material and the winter protection material inseparabler, and the heat also is difficult for running off to can further promote thermal-insulated effect.

Referring to fig. 1, fig. 1 is a schematic diagram of a sound-absorbing noise-reducing polyimide foam cold-proof material product structure provided by the present invention. Wherein 1 is polyimide foam; 2 is an environment-friendly adhesive.

The invention also provides the sound absorption and noise reduction type polyimide foam material in any one of the technical schemes, the sound absorption and noise reduction type cold-proof material in any one of the technical schemes or the sound absorption and noise reduction type cold-proof material prepared by the preparation method in any one of the technical schemes, and the application of the sound absorption and noise reduction type cold-proof material in the aspects of vehicles or rail transit. The vehicle and rail transit aspect can be a high-speed train.

According to the sound absorption and noise reduction type polyimide foam, the sound absorption and noise reduction type high-speed train cold-proof material and the application, the hollow glass beads are added into the polyimide foam material, the transmission path of sound waves is prolonged after the sound waves enter the foam, and meanwhile, the absorption of the sound waves is increased due to the cavity resonance effect of the hollow glass beads; then, the softening process is utilized to enable the cavities in the polyimide foam cold-proof material to be mutually communicated to form a sound absorption structure, so that after sound enters the cavities, the sound is continuously refracted, reflected and frictionally heated to be dissipated; and then, by combining the introduction of the silencing wedge structure, the acoustic impedance of the material is better matched with that of air, sound is efficiently absorbed, and the sound absorption and noise reduction performance of the polyimide foam material is greatly improved. After the sound waves are incident, the sound waves and the hollow glass beads generate certain interaction, so that the propagation path of the sound waves in the polyimide foam cold-proof material is prolonged, and the attenuation performance of the material to the sound waves is enhanced; on the other hand, according to the sound absorption principle of the material, the hollow glass beads have the cavity resonance sound absorption effect and can generate microphase separation with the cold-proof material matrix, so that the sound absorption performance of the material can be enhanced. In addition, the interaction between the glass beads and the cold-proof material matrix can increase the internal friction of the system, thereby increasing the loss of the material to incident sound energy and improving the sound absorption performance of the material. The wedge is established, when noise is incident from the tip, the acoustic impedance of the material can be well matched with that of air, the noise is efficiently absorbed, and the sound absorption characteristic of the wedge structure can be effectively improved by adjusting the length of the wedge, the depth of the cavity and the like. Specific raw material selection and component proportion in the polyimide foam are combined, and specific hollow glass beads are adopted, so that the strength, rigidity, stability, impact toughness and other characteristics of the polyimide foam cold-proof material can be improved, and the sound absorption and noise reduction performance of the polyimide foam cold-proof material for the high-speed rail is further improved.

According to the sound absorption and noise reduction type polyimide foam provided by the invention, hollow glass beads are added to form cavity resonance, the material is softened, a sound absorption wedge structure is introduced to improve the matching degree of the acoustic impedance of the material and the acoustic impedance of air, and specific raw material selection and component proportion are combined, so that the sound absorption and noise reduction performance of the polyimide foam cold-proof material for high-speed rails is further improved, a technical foundation is laid for the preparation of the high-performance heat insulation and sound absorption integrated function cold-proof material, the preparation process flow of the polyimide foam cold-proof material is simple, the later-stage loading is convenient and rapid, and a new thought is provided for the improvement of the sound absorption performance of the high-speed rail cold-proof material.

For further illustration of the present invention, the following detailed description will be made of the sound absorbing and noise reducing polyimide foam, the sound absorbing and noise reducing cold-proof material and the application thereof provided by the present invention with reference to the following examples, but it should be understood that the present invention is carried out on the premise of the technical solution of the present invention, and the detailed embodiments and the specific operation procedures are given only for further illustration of the features and advantages of the present invention, not for limiting the claims of the present invention, and the scope of the present invention is not limited to the following examples.

Example 1

Vacuum dewatering 20 weight portions of hollow glass microballoon at 200 deg.c for 8 hr. Pouring 25 parts by weight of polyphenyl polymethylene polyisocyanate into a material tank A; uniformly stirring 30 parts by weight of N, N' -dimethylformamide, 50 parts by weight of pyromellitic dianhydride and 10 parts by weight of diethylene glycol bis (2-chloroethyl) phosphate, and pouring into a tank B; mixing 10 parts by weight of hollow glass beads, 20 parts by weight of a silane coupling agent, 5 parts by weight of methanol, 5 parts by weight of dibutyltin dilaurate and 10 parts by weight of polyether modified silicone oil, stirring at 1500rpm for 2 hours, and pouring into a tank C after stirring; respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials; the flow rates of the tank A, the tank B and the tank C are accurately controlled by a computer, the tank A, the tank B and the tank C are mixed at a high speed through a closed mixing cavity and then injected into a mold for foaming, and the sound-absorbing noise-reducing polyimide foam material can be prepared after molding and curing. Setting the temperature of a flat plate oil press to be 60 ℃, placing the polyimide foam which is primarily cut on a press, pressurizing to 5MPa, and carrying out softening treatment for 15 min. Cutting the polyimide foam into a three-wedge structure with the height of 50mm and the interval of wedge tops of 1cm, and coating a UV curing adhesive on the back to obtain the sound absorption and noise reduction polyimide foam-proof cold-proof material for the high-speed rail.

The sound-absorbing noise-reducing polyimide foam cold-proof material for the high-speed rail prepared in the embodiment 1 of the invention is subjected to performance test.

Referring to table 1, table 1 shows the performance parameters of the sound-absorbing and noise-reducing polyimide foam cold-proof materials prepared in examples 1 to 7 of the present invention.

Example 2

And (3) dehydrating 20 parts by weight of hollow glass microspheres at 200 ℃ in vacuum for 8 hours for later use. Pouring 25 parts by weight of polyphenyl polymethylene polyisocyanate into a material tank A; uniformly stirring 30 parts by weight of N, N' -dimethylformamide, 50 parts by weight of pyromellitic dianhydride and 10 parts by weight of diethylene glycol bis (2-chloroethyl) phosphate, and pouring into a tank B; mixing 15 parts by weight of hollow glass beads, 20 parts by weight of a silane coupling agent, 5 parts by weight of methanol, 5 parts by weight of dibutyltin dilaurate and 10 parts by weight of polyether modified silicone oil, stirring at 1500rpm for 2 hours, and pouring into a tank C after stirring; respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials; the flow rates of the tank A, the tank B and the tank C are accurately controlled by a computer, the tank A, the tank B and the tank C are mixed at a high speed through a closed mixing cavity and then injected into a mold for foaming, and the sound-absorbing noise-reducing polyimide foam material can be prepared after molding and curing. Setting the temperature of a flat plate oil press to be 60 ℃, placing the polyimide foam which is primarily cut on a press, pressurizing to 5MPa, and carrying out softening treatment for 15 min. Cutting the polyimide foam into a three-wedge structure with the height of 50mm and the interval of wedge tops of 1cm, and coating a UV curing adhesive on the back to obtain the sound absorption and noise reduction polyimide foam-proof cold-proof material for the high-speed rail.

The sound-absorbing noise-reducing polyimide foam cold-proof material for the high-speed rail prepared in the embodiment 2 of the invention is subjected to performance test.

Referring to table 1, table 1 shows the performance parameters of the sound absorption and noise reduction polyimide foam cold-proof material prepared in examples 1 to 7 of the present invention.

Example 3

Vacuum dewatering 20 weight portions of hollow glass microballoon at 200 deg.c for 8 hr. Pouring 25 parts by weight of polyphenyl polymethylene polyisocyanate into a material tank A; uniformly stirring 30 parts by weight of N, N' -dimethylformamide, 50 parts by weight of pyromellitic dianhydride and 10 parts by weight of diethylene glycol bis (2-chloroethyl) phosphate, and pouring into a tank B; mixing 20 parts by weight of hollow glass beads, 20 parts by weight of a silane coupling agent, 5 parts by weight of methanol, 5 parts by weight of dibutyltin dilaurate and 10 parts by weight of polyether modified silicone oil, stirring at 1500rpm for 2 hours, and pouring into a tank C after stirring; respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials; the flow rates of the tank A, the tank B and the tank C are accurately controlled by a computer, the tank A, the tank B and the tank C are mixed at a high speed through a closed mixing cavity and then injected into a mold for foaming, and the sound-absorbing noise-reducing polyimide foam material can be prepared after molding and curing. Setting the temperature of a flat plate oil press to be 60 ℃, placing the polyimide foam which is initially cut on a press, pressurizing at 5MPa, and softening for 15 min. Cutting the polyimide foam into a three-wedge structure with the height of 50mm and the interval of wedge top ends of 1cm, and coating a UV curing adhesive on the back to obtain the sound-absorbing noise-reducing polyimide foam-proof cold-proof material for the high-speed rail.

The sound-absorbing noise-reducing polyimide foam cold-proof material for the high-speed rail prepared in the embodiment 3 of the invention is subjected to performance test.

Example 4

Vacuum dewatering 20 weight portions of hollow glass microballoon at 200 deg.c for 8 hr. Pouring 25 parts by weight of polyphenyl polymethylene polyisocyanate into a material tank A; uniformly stirring 30 parts by weight of N, N' -dimethylformamide, 50 parts by weight of pyromellitic dianhydride and 10 parts by weight of diethylene glycol bis (2-chloroethyl) phosphate, and pouring into a tank B; mixing 20 parts by weight of hollow glass beads, 20 parts by weight of a silane coupling agent, 5 parts by weight of methanol, 5 parts by weight of dibutyltin dilaurate and 10 parts by weight of polyether modified silicone oil, stirring at 1500rpm for 2 hours, and pouring into a tank C after stirring; respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials; the flow rates of the tank A, the tank B and the tank C are accurately controlled by a computer, the tank A, the tank B and the tank C are mixed at a high speed through a closed mixing cavity and then injected into a mold for foaming, and the sound absorption and noise reduction polyimide foam material can be prepared after molding and curing. Setting the temperature of a flat plate oil press to be 60 ℃, placing the polyimide foam which is initially cut on a press, pressurizing at 5MPa, and softening for 15 min. Cutting the polyimide foam into a three-wedge structure with the height of 80mm and the interval of wedge top ends of 1cm, and coating a UV curing adhesive on the back to obtain the sound-absorbing noise-reducing polyimide foam-proof cold-proof material for the high-speed rail.

The sound-absorbing noise-reducing polyimide foam cold-proof material for the high-speed rail prepared in the embodiment 4 of the invention is subjected to performance test.

Example 5

And (3) dehydrating 20 parts by weight of hollow glass microspheres at 200 ℃ in vacuum for 8 hours for later use. Pouring 25 parts by weight of polyphenyl polymethylene polyisocyanate into a material tank A; uniformly stirring 30 parts by weight of N, N' -dimethylformamide, 50 parts by weight of pyromellitic dianhydride and 10 parts by weight of diethylene glycol bis (2-chloroethyl) phosphate, and pouring into a tank B; mixing 20 parts by weight of hollow glass beads, 20 parts by weight of a silane coupling agent, 5 parts by weight of methanol, 5 parts by weight of dibutyltin dilaurate and 10 parts by weight of polyether modified silicone oil, stirring at 1500rpm for 2 hours, and pouring into a tank C after stirring; respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials; the flow rates of the tank A, the tank B and the tank C are accurately controlled by a computer, the tank A, the tank B and the tank C are mixed at a high speed through a closed mixing cavity and then injected into a mold for foaming, and the sound-absorbing noise-reducing polyimide foam material can be prepared after molding and curing. Setting the temperature of a flat plate oil press to be 60 ℃, placing the polyimide foam which is initially cut on a press, pressurizing at 5MPa, and softening for 15 min. Cutting the polyimide foam into a three-wedge structure with the height of 50mm and the interval of wedge tops of 2cm, and coating a UV curing adhesive on the back to obtain the sound absorption and noise reduction polyimide foam-proof cold-proof material for the high-speed rail.

The sound-absorbing noise-reducing polyimide foam cold-proof material for the high-speed rail prepared in the embodiment 5 of the invention is subjected to performance test.

Example 6

Vacuum dewatering 20 weight portions of hollow glass microballoon at 200 deg.c for 8 hr. Pouring 25 parts by weight of polyphenyl polymethylene polyisocyanate into a material tank A; uniformly stirring 30 parts by weight of N, N' -dimethylformamide, 50 parts by weight of pyromellitic dianhydride and 10 parts by weight of diethylene glycol bis (2-chloroethyl) phosphate, and pouring into a tank B; mixing 20 parts by weight of hollow glass beads, 20 parts by weight of a silane coupling agent, 5 parts by weight of methanol, 5 parts by weight of dibutyltin dilaurate and 10 parts by weight of polyether modified silicone oil, stirring at 1500rpm for 2 hours, and pouring into a tank C after stirring; respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials; the flow rates of the tank A, the tank B and the tank C are accurately controlled by a computer, the tank A, the tank B and the tank C are mixed at a high speed through a closed mixing cavity and then injected into a mold for foaming, and the sound-absorbing noise-reducing polyimide foam material can be prepared after molding and curing. And cutting the sound absorption and noise reduction polyimide foam material, and coating a UV curing adhesive on the back to obtain the sound absorption and noise reduction polyimide foam-proof cold-proof material for the high-speed rail.

The sound-absorbing noise-reducing polyimide foam cold-proof material for the high-speed rail prepared in the embodiment 6 of the invention is subjected to performance test.

Example 7

Vacuum dewatering 20 weight portions of hollow glass microballoon at 200 deg.c for 8 hr. Pouring 25 parts by weight of polyphenyl polymethylene polyisocyanate into a material tank A; uniformly stirring 30 parts by weight of N, N' -dimethylformamide, 50 parts by weight of pyromellitic dianhydride and 10 parts by weight of diethylene glycol bis (2-chloroethyl) phosphate, and pouring into a tank B; mixing 20 parts by weight of hollow glass beads, 20 parts by weight of a silane coupling agent, 5 parts by weight of methanol, 5 parts by weight of dibutyltin dilaurate and 10 parts by weight of polyether modified silicone oil, stirring at 1500rpm for 2 hours, and pouring into a tank C after stirring; respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials; the flow rates of the tank A, the tank B and the tank C are accurately controlled by a computer, the tank A, the tank B and the tank C are mixed at a high speed through a closed mixing cavity and then injected into a mold for foaming, and the sound-absorbing noise-reducing polyimide foam material can be prepared after molding and curing. Setting the temperature of a flat plate oil press to be 60 ℃, placing the polyimide foam which is primarily cut on a press, pressurizing to 5MPa, and carrying out softening treatment for 15 min. And coating the back of the treated material with a UV curing adhesive to obtain the sound-absorbing noise-reducing polyimide anti-foaming cold-proof material for the high-speed rail.

The sound-absorbing noise-reducing polyimide foam cold-proof material for high-speed rails prepared in example 7 of the invention was subjected to a performance test.

TABLE 1

As can be seen from comparison of data in table 1, in examples 1 to 3, hollow glass beads with different contents are selected, the density of the polyimide foam cold-proof material is increased along with the increase of the content of the hollow glass beads, the heat conductivity coefficient is not changed too much, the sound absorption coefficient is obviously improved, and when 20 parts by weight of the hollow glass beads are added, the sound absorption coefficient reaches 0.71; example 4 the wedge height was increased on the basis of example 3, the sound absorption coefficient reached 0.73, and the thermal conductivity was unchanged; example 5 increases the pitch of the wedges on the basis of example 3, and the sound absorption performance is reduced. In example 6, the sound absorption coefficient is reduced compared with that of example 3 only by adding 20 parts by weight of hollow glass beads; example 7 in example 6, the material was softened to improve the sound absorption coefficient.

Therefore, the sound absorption performance of the polyimide foam cold-proof material for the high-speed rail is improved by comprehensive application of softening treatment, the hollow glass beads and the silencing wedge structures.

The above detailed description of the present invention provides a sound absorption and noise reduction type polyimide foam, and a sound absorption and noise reduction type high-speed railway cold-proof material and application thereof, and the principle and embodiments of the present invention are described herein by using specific examples, which are provided only for helping to understand the method and the core idea of the present invention, including the best mode, and also for enabling any person skilled in the art to practice the present invention, including making and using any device or system, and implementing any method in combination. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. The sound absorption and noise reduction type polyimide foam cold-proof material is characterized by comprising the following steps:

vacuum dehydrating 20 parts by weight of hollow glass microspheres at 200 ℃ for 8 hours for later use;

pouring 25 parts by weight of polyphenyl polymethylene polyisocyanate into a material tank A; uniformly stirring 30 parts by weight of N, N' -dimethylformamide, 50 parts by weight of pyromellitic dianhydride and 10 parts by weight of diethylene glycol bis (2-chloroethyl) phosphate, and pouring into a tank B; mixing 20 parts by weight of hollow glass beads, 20 parts by weight of a silane coupling agent, 5 parts by weight of methanol, 5 parts by weight of dibutyltin dilaurate and 10 parts by weight of polyether modified silicone oil, stirring at 1500rpm for 2 hours, and pouring into a tank C after stirring; respectively stirring the tanks A, B and C, and vacuumizing and filling nitrogen for multiple times to remove air in the raw materials; accurately controlling the flow rates of the raw materials of the tanks A, B and C by a computer, mixing the raw materials at a high speed through a closed mixing cavity, injecting the mixture into a mold for foaming, and preparing the sound-absorbing noise-reducing polyimide foam material after molding and curing;

setting the temperature of a flat plate oil press to be 60 ℃, placing the polyimide foam which is primarily cut on a press, pressurizing to 5MPa, and performing softening treatment for 15 min;

and cutting the polyimide foam into a three-wedge structure with the height of 80mm and the interval of wedge tops of 1cm, and coating a UV (ultraviolet) curing adhesive on the back to obtain the sound-absorbing noise-reducing polyimide foam cold-proof material.

2. Use of the sound absorbing and noise reducing polyimide foam cold protective material as claimed in claim 1 in vehicles or rail traffic.