Soundproofing carpet material composition, material and its use in automotive interiors

Abstract

The application discloses a sound insulation carpet material composition, a material and application of the material to automotive interiors, and relates to the technical field of sound insulation carpet materials.The sound insulation carpet material composition comprises, by weight, 20-50 parts of a thermoplastic resin matrix, 40-80 parts of inorganic sound insulation fillers and 1-10 parts of a hyperbranched interface damping modifier.The application realizes in-situ chemical bonding by using the hyperbranched modifier, enhances the mechanical strength and flexibility of the high-filling material, improves the damping and sound insulation performance through intramolecular friction, improves the processing fluidity by using the low-viscosity characteristic, avoids the introduction of small-molecule additives, and realizes low odor and low VOC emission of the material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sound insulation carpet materials, in particular to a sound insulation carpet material composition, a material and application thereof in automotive interiors. BACKGROUND

[0002] As a core automotive interior functional part, the automotive sound insulation carpet is mainly laid above the body chassis sheet metal, plays a role in decorating the vehicle interior environment and blocking road vibration noise and engine noise from entering the vehicle, and its structure usually includes a surface decoration layer and a back coating layer with sound insulation function. Mainly using the principle of mass law, the surface density of the material is increased to reflect and block the sound energy, thereby improving the acoustic comfort of the vehicle interior.

[0003] In the manufacturing process of the back coating layer, in order to obtain a higher surface density, a thermoplastic resin is usually used as a matrix, mixed with a high proportion of heavy inorganic mineral filler, and then extruded or calendered after melt blending. In actual production, in order to pursue better quietness, the filling proportion of inorganic fillers is often very high, and the resin matrix needs to wrap a large amount of inorganic particles and form a continuous sheet structure, which is then installed on the complex body chassis curved surface.

[0004] However, under such a high filling condition, due to the large difference in physical and chemical properties between the inorganic filler and the organic resin matrix, and the weak interface bonding, a series of performance defects are easily caused. When subjected to external impact or long-term vibration in driving, the material exhibits brittle characteristics and is prone to cracking and even filler shedding, resulting in a decrease in mechanical properties and structural integrity. At the same time, the simple physical mixing structure has insufficient mechanical vibration energy dissipation capacity, making it difficult to meet the high-quality demand for sound insulation and noise reduction effect of the material in the low-frequency band. In addition, in order to improve the processing fluidity of the high-filling system, some small-molecule processing aids are sometimes introduced in the prior art, which easily leads to the presence of unpleasant odor in the vehicle and the risk of exceeding the volatile organic compounds. SUMMARY

[0005] The purpose of the present application is to provide a sound insulation carpet material composition, a material and application thereof in automotive interiors, which solves the problems in the background art.

[0006] To solve the above technical problems, the present application provides a sound insulation carpet material composition, which comprises, by weight:

[0007] 20-50 parts of a thermoplastic resin matrix;

[0008] 40-80 parts of an inorganic sound insulation filler; and

[0009] 1-10 parts of a hyperbranched interface damping modifier;

[0010] wherein the hyperbranched interfacial damping modifier has a hyperbranched polyester core skeleton, the terminal hydroxyl groups of the core skeleton are grafted with alkoxysilane groups via urethane linkages, and the remaining groups are grafted with hydrophobic long-chain alkyl groups or hindered phenol groups via ester linkages; the alkoxysilane groups can hydrolyze during processing and form chemical bonds with the hydroxyl groups on the surface of the inorganic sound insulation filler, and the hydrophobic long-chain alkyl groups or hindered phenol groups can form physical entanglements or compatibilization with the thermoplastic resin matrix.

[0011] Preferably, the composition comprises, by weight parts:

[0012] 25-40 parts of a thermoplastic resin matrix;

[0013] 50-75 parts of an inorganic sound insulation filler;

[0014] 2-5 parts of a hyperbranched interfacial damping modifier;

[0015] wherein the thermoplastic resin matrix is selected from at least one of polypropylene, thermoplastic elastomer, or ethylene-vinyl acetate copolymer;

[0016] the inorganic sound insulation filler is selected from at least one of barium sulfate, calcium carbonate, or mica powder, and the particle size of the inorganic sound insulation filler is ≤ 15 μm.

[0017] Preferably, the raw materials for preparing the hyperbranched interfacial damping modifier include trimethylolpropane, dimethylolpropionic acid, 3-isocyanatopropyl triethoxysilane, and long-chain fatty acid or hindered phenol acid;

[0018] wherein the alkoxysilane groups are derived from the addition reaction of 3-isocyanatopropyl triethoxysilane and the terminal hydroxyl groups of the core skeleton;

[0019] the hydrophobic long-chain groups are derived from the esterification reaction of the long-chain fatty acid and the terminal hydroxyl groups of the core skeleton; and the hindered phenol groups are derived from the esterification reaction of the hindered phenol acid and the terminal hydroxyl groups of the core skeleton.

[0020] The long-chain fatty acid is selected from at least one of stearic acid, lauric acid, or palmitic acid.

[0021] Preferably, the method for preparing the sound insulation carpet material composition comprises:

[0022] Step S1, preparing a hyperbranched interfacial damping modifier;

[0023] Step S2, pre-mixing the thermoplastic resin matrix, the inorganic sound insulation filler, and the hyperbranched interfacial damping modifier to obtain a pre-mixed material;

[0024] Step S3, adding the pre-mixed material into a twin-screw extruder to perform in-situ reactive extrusion in a molten state, and then cooling and granulating to obtain the sound insulation carpet material composition.

[0025] Preferably, step S1 specifically comprises:

[0026] Step S11, constructing the core skeleton: trimethylolpropane and dimethylolpropionic acid are added into a reaction kettle in a molar ratio of 1:10-1:20, under the protection of nitrogen and mechanical stirring, the temperature is raised to 130-150°C in a gradient heating mode for melt polycondensation reaction, and the reaction process is continuously dehydrated by vacuum pumping to reduce pressure until the acid value of the product is reduced to below 5 mgKOH / g, to obtain a hydroxyl-terminated hyperbranched polyester;

[0027] Step S12, introducing damping units: long-chain fatty acids or acids with hindered phenol structure are added to the hydroxyl-terminated hyperbranched polyester, and esterification reaction is carried out under the conditions of 140-160°C and negative pressure, and the byproduct water is removed by condensing device or vacuum pumping, until no water is generated, to obtain an intermediate;

[0028] Step S13, introducing anchoring units: the intermediate is dissolved in anhydrous aprotic polar solvent, cooled to 60-80°C, and dibutyltin dilaurate is added as a catalyst, and 3-isocyanatopropyl triethoxysilane is added dropwise at constant pressure, and after the dropwise addition is completed, the reaction is incubated for 2-4 hours, so that the isocyanate group reacts with the remaining hydroxyl group to form a hyperbranched interfacial damping modifier.

[0029] Preferably, in step S12, the molar ratio of the hydroxyl group of the hydroxyl-terminated hyperbranched polyester to the long-chain fatty acid or the carboxylic acid with hindered phenol structure is 1:0.4-0.8; in step S13, the molar ratio of the hydroxyl group of the hydroxyl-terminated hyperbranched polyester to 3-isocyanatopropyl triethoxysilane is 1:0.1-0.4.

[0030] Preferably, in step S3, the barrel temperature of the twin-screw extruder is set to 140-210°C, and the screw rotation speed is 200-400 rpm, in the closed reaction section, water hydrolysis reaction is initiated by water adsorbed on the surface of the raw materials or additional 0.05-0.5 parts by weight of water; in the vacuum exhaust section, vacuum exhaust with a vacuum degree ≥0.08 MPa is opened to remove reaction byproducts and small molecular volatile substances; during in-situ reactive extrusion, the alkoxysilane group of the hyperbranched interfacial damping modifier is hydrolyzed under the action of high temperature shear and trace amount of water, and condensation reaction occurs in-situ with the hydroxyl group on the surface of the inorganic sound insulation filler to form a chemical bonded interface.

[0031] Also provided is a sound insulation carpet material, which comprises a surface decoration layer and a back coating layer, and the back coating layer is made of a sound insulation carpet material composition.

[0032] Preferably, the thickness of the back coating layer is 1.5-4.0 mm, and the sound transmission loss STL of the sound insulation carpet in the frequency range of 100-500 Hz is ≥25 dB.

[0033] The application also provides a soundproof carpet material for use in the interior of a vehicle, which is arranged above the chassis panel of the vehicle and used for blocking low-frequency vibration noise from the road surface and high-frequency noise from the engine.

[0034] Compared with the prior art, the application has the following beneficial effects:

[0035] By introducing the hyperbranched polymer with a specific spatial structure into the formula system, the special end group functional groups of the hyperbranched polymer are used to react with the surface of the inorganic filler in situ during the processing, a stable molecular connecting bridge is constructed between the inorganic filler particles and the organic resin matrix, the interface compatibility is effectively improved, the soundproof carpet can withstand greater external force deformation without being easily damaged while maintaining a high filling amount to ensure the sound density, and the soundproof carpet is endowed with excellent mechanical bearing capacity and flexibility, so that the soundproof carpet is not prone to cracking or damage in the complex installation process and the long-term vibration environment of the vehicle.

[0036] The specific long chain or group with a steric hindering effect in the molecular structure is used to form a physical entanglement network with the resin matrix, under the excitation of sound waves or mechanical vibration, strong internal friction occurs between the molecular chain segments in the restricted state and between the molecular chain and the matrix, the mechanical energy carried by the sound waves can be converted into heat energy and dissipated, so that the loss factor of the material is effectively improved, the soundproof carpet has better sound transmission loss performance in blocking low-frequency vibration noise from the road surface and high-frequency noise from the engine, and the quietness in the vehicle is improved.

[0037] The low melt viscosity characteristic brought by the special hyperbranched topological structure of the functional additive can effectively improve the flowability of the high-filling composite material in the melt processing process, so that the material does not need to rely on traditional small molecule plasticizers or lubricants in the extrusion molding process, thereby avoiding the migration or volatilization of small molecule substances in the later use process, meeting the strict standards of air quality for the interior of the vehicle and providing a more healthy and comfortable driving environment for the passengers. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings;

[0039] Figure 1 It is a tensile strength comparison chart of the soundproof carpet material of the application;

[0040] Figure 2 It is a breaking elongation comparison chart of the soundproof carpet material of the application;

[0041] Figure 3 Sound transmission loss at 500Hz for the soundproofing carpet material of the present invention;

[0042] Figure 4 Loss factor for the soundproofing carpet material of the present invention;

[0043] Figure 5 Odor rating test for the material of the present invention. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0045] The embodiment part of the specification aims to elaborate a soundproofing carpet material composition, a material and its application in automotive interior decoration; the core of the technical solution is to solve the technical problems of poor interfacial bonding force, brittle mechanical properties and low damping energy consumption efficiency commonly existing in existing high-filled soundproofing materials;

[0046] In the technical concept of the present application, the hyperbranched interfacial damping modifier is not a universal additive, but a multifunctional molecular tool constructed in the specific technical environment of the present application; the term hyperbranched interfacial damping modifier specifically refers to a polymer with a spherical spatial structure, which utilizes the low melt viscosity and cavity scattering effect provided by the hyperbranched polyester core skeleton, combines the chemical anchoring effect of alkoxysilane groups on inorganic fillers, and the physical entanglement and internal friction energy dissipation effect of hydrophobic long-chain alkyl or hindered phenol groups on the resin matrix, to construct in-situ inorganic-organic strong interaction interface during processing; this design is not a simple superposition, but utilizes the synergistic effect of different functional groups in the in-situ reactive extrusion process to simultaneously achieve the chemical enhancement of the interface and the improvement of the acoustic damping performance;

[0047] The technical solutions of the present application will be clearly and completely described below with reference to specific embodiments; the experimental methods not specified in the embodiments are usually performed according to conventional conditions or according to the conditions suggested by the manufacturer; unless otherwise specified, all percentages, ratios, proportions or parts are by weight.

[0048] Example 1

[0049] The embodiment provides a sound insulation carpet material composition, in the embodiment, the preparation process of the hyperbranched interface damping modifier is as follows: step S11 is performed to construct a core skeleton: trimethylolpropane and dihydroxymethyl propionic acid are added into a reaction kettle at a molar ratio of 1:15; under the protection of nitrogen and mechanical stirring, a gradient temperature rising mode is adopted to heat to 140 DEG C for melt polycondensation reaction; vacuum dewatering is continuously performed during the reaction until the acid value of the product is reduced to 4.5 mgKOH / g, and a hydroxyl-terminated hyperbranched polyester is obtained; then, step S12 is performed to introduce a damping unit: stearic acid is added to the hydroxyl-terminated hyperbranched polyester as a long-chain fatty acid, wherein the molar ratio of the hydroxyl group of the hydroxyl-terminated hyperbranched polyester to the stearic acid is controlled to be 1:0.6; esterification reaction is performed at 150 DEG C and under negative pressure, and the by-product water is removed by using a condensing device, until no water is generated, and an intermediate is obtained; at this time, the hydrophobic long-chain alkyl group has been successfully grafted to the skeleton, for providing subsequent physical entanglement and damping friction; finally, step S13 is performed to introduce an anchoring unit: the intermediate is dissolved in anhydrous dimethylformamide (an aprotic polar solvent), cooled to 70 DEG C, and dibutyltin dilaurate is added as a catalyst, and 3-isocyanatopropyl triethoxysilane is added dropwise at a constant pressure; the molar ratio of the original hydroxyl group of the hydroxyl-terminated hyperbranched polyester to 3-isocyanatopropyl triethoxysilane is set to be 1:0.3; after the dropwise addition is completed, the reaction is kept for 3 hours, so that the isocyanate group and the remaining hydroxyl group are subjected to addition reaction; after the reaction is completed, the reaction liquid is slowly poured into 5 times the volume of anhydrous ethanol / n-hexane mixed liquid (volume ratio 1:1) for sedimentation, and the precipitate is collected by filtration; the precipitate is washed with anhydrous ethanol for 3 times, so as to completely remove the residual dimethylformamide solvent; finally, the product is placed in a vacuum oven at 80 DEG C and dried for 12 hours until the weight is constant, and the hyperbranched interface damping modifier without odor is obtained.

[0050] The soundproof carpet material composition was prepared by using the above modifier: 35 parts of polypropylene as the thermoplastic resin matrix, 60 parts of barium sulfate with a particle size of 10 μm as the inorganic soundproof filler, and 5 parts of the hyperbranched interface damping modifier were weighed by weight parts; when pre-mixed in a high-speed mixer, 0.3 parts of deionized water was added to the mixture by spraying to wet the surface of the filler to provide the trace amount of water required for hydrolysis, and a premix was obtained. Then the premix was added to a twin-screw extruder; the barrel temperature of the twin-screw extruder was set to 190°C, and the screw speed was 300 rpm; the length-diameter ratio of the twin-screw extruder was 44:1, and the strong shear closed reaction zone was set at L / D=20~30, and the vacuum exhaust zone was set at L / D=36 (vacuum degree-0.09 MPa); during the in-situ reactive extrusion process, the alkoxysilane groups of the hyperbranched interface damping modifier rapidly hydrolyzed under the action of high temperature shear in the closed reaction zone and the pre-added trace amount of water, and in-situ condensation reaction occurred with the hydroxyl groups on the surface of the barium sulfate to form a chemical bonded interface; then in the vacuum exhaust zone, the small molecule alcohol and water vapor generated by the reaction were removed in time; after cooling and granulation, the soundproof carpet material composition was obtained;

[0051] The material was made into a back coating layer with a thickness of 2.5 mm and laid on the top of the simulated automobile chassis sheet metal for testing; the results showed that the material had good flowability during processing, and the surface of the prepared carpet back coating layer was smooth; due to the chemical bonding effect of the hyperbranched interface damping modifier, the inorganic filler was tightly combined with the matrix, effectively improving the mechanical properties of the material; at the same time, the intramolecular friction of the long-chain alkyl group was utilized to improve the acoustic damping effect of the material.

[0052] Example 2

[0053] This example aims to verify the effect of the present application under high filling amount conditions;

[0054] In this example, the preparation parameters of the hyperbranched interface damping modifier were adjusted as follows: in step S11, the molar ratio of trimethylolpropane to dimethylolpropionic acid was 1:20; in step S12, the acid 3,5-di-tert-butyl-4-hydroxybenzenepropionic acid with a hindered phenol structure was selected to replace stearic acid to enhance the damping performance brought by the steric hindrance effect; the molar ratio of the hydroxyl groups of the hydroxyl-terminated hyperbranched polyester to the acid was 1:0.5; in step S13, the molar ratio of the hydroxyl groups of the hydroxyl-terminated hyperbranched polyester to 3-isocyanatopropyltriethoxysilane was 1:0.4;

[0055] The formula and preparation of the soundproof carpet material composition were adjusted as follows: the composition included 20 parts of a thermoplastic elastomer as the thermoplastic resin matrix; 75 parts of calcium carbonate as the inorganic soundproof filler, with a particle size of 5 μm; and 5 parts of the hyperbranched interface damping modifier; in the extrusion process, the barrel temperature was set to 180°C, and the screw speed was 250 rpm;

[0056] In this embodiment, although the inorganic sound insulation filler is as high as 75 parts, which usually causes the material to be extremely brittle, the obtained material still maintains good flexibility due to the high anchoring effect of the hyperbranched interfacial damping modifier and the lubricating effect of the hyperbranched structure; the hindered phenol group produces strong internal friction under the excitation of sound waves, so that the sound insulation carpet material exhibits excellent performance in low-frequency noise blocking, and is particularly suitable for the chassis sound insulation of luxury vehicles with extremely high quietness requirements.

[0057] Example 3

[0058] This embodiment aims to verify the effect of different resin matrices and lower modifier amounts.

[0059] In this embodiment, the preparation parameters of the hyperbranched interfacial damping modifier are adjusted as follows: in step S11, the molar ratio of trimethylolpropane to dimethylolpropionic acid is 1:10; in step S12, lauric acid is selected as the source of hydrophobic long chains; the molar ratio of the hydroxyl groups of the hydroxyl-terminated hyperbranched polyester to lauric acid is 1:0.8; in step S13, the molar ratio of the hydroxyl groups of the hydroxyl-terminated hyperbranched polyester to 3-isocyanatopropyl triethoxysilane is 1:0.2.

[0060] The formula and preparation of the sound insulation carpet material composition are adjusted as follows: the composition includes, by weight parts, 50 parts of ethylene-vinyl acetate copolymer as the thermoplastic resin matrix; 48 parts of mica powder as the inorganic sound insulation filler; 2 parts of the hyperbranched interfacial damping modifier; in the extrusion process, the barrel temperature is set to 150°C, and the screw rotation speed is 200 rpm.

[0061] In this embodiment, the proportion of the thermoplastic resin matrix is relatively high, and the flexibility of the material itself is good; the introduction of a small amount of the hyperbranched interfacial damping modifier mainly utilizes its chemical bonding ability on the surface of the flaky mica powder to prevent the agglomeration of the mica powder in the matrix; tests show that even at a low addition amount, the alkoxy silane group can effectively improve the dispersibility of the mica powder, and in combination with the compatibilization effect of the hydrophobic long chain group, the tensile strength of the sound insulation carpet is significantly improved, and no odor is generated.

[0062] Example 4

[0063] This embodiment aims to verify the limit of the damping performance improvement with high modifier content.

[0064] The preparation of the hyperbranched interfacial damping modifier is consistent with that of Example 1.

[0065] The formulation and preparation of the soundproof carpet material composition are adjusted as follows: the composition comprises, by weight parts, 30 parts of a mixture of polypropylene and a thermoplastic elastomer in a mass ratio of 1:1 as a thermoplastic resin matrix, 60 parts of barium sulfate, and 10 parts of a hyperbranched interfacial damping modifier; in the extrusion process, the barrel temperature is set to 200°C, and the screw rotation speed is 350 rpm;

[0066] In this embodiment, a higher content of the hyperbranched interfacial damping modifier builds a thick interfacial damping layer between the thermoplastic resin matrix and the inorganic soundproof filler; the cavity structure of the hyperbranched polyester core skeleton and the hydrophobic long-chain alkyl group jointly greatly dissipate sound wave energy; when applied to automotive interiors, the formulation shows superior sound transmission loss performance in blocking high-frequency noise from the engine compared to conventional materials.

[0067] Example 5

[0068] This embodiment aims to verify the influence of changes in process parameters on the effect of reactive extrusion;

[0069] The preparation of the hyperbranched interfacial damping modifier is consistent with that in Example 1; the formulation of the soundproof carpet material composition is consistent with that in Example 1;

[0070] In the preparation method, the parameters of step S3 are adjusted as follows: the barrel temperature of the twin-screw extruder is set to 210°C, and the screw rotation speed is 400 rpm;

[0071] Under this higher processing temperature and shear rate, the hydrolysis and condensation reaction of the alkoxysilane groups in the hyperbranched interfacial damping modifier is more complete, and the grafting rate on the surface of the inorganic soundproof filler is higher; at the same time, strong shear action promotes the hydrophobic long-chain alkyl group to be more deeply dispersed in the thermoplastic resin matrix; test results show that the soundproof carpet material prepared by this process has excellent thermal stability and is not prone to performance degradation under long-term high temperature.

[0072] Comparative Example 1

[0073] This comparative example is used to illustrate the case without adding a modifier; formulation: 35 parts of polypropylene and 65 parts of barium sulfate; preparation method: simple physical blending extrusion, with the same process parameters as in Example 1; due to the lack of a hyperbranched interfacial damping modifier, there is only weak physical bonding between the inorganic soundproof filler and the thermoplastic resin matrix.

[0074] Comparative Example 2

[0075] This comparative example is used to illustrate the case of using conventional small molecule coupling agent instead of the modifier of the present application; formulation: 35 parts of polypropylene, 60 parts of barium sulfate, 5 parts of γ-aminopropyl triethoxysilane; preparation method: same as example 1; although γ-aminopropyl triethoxysilane contains silane groups capable of reacting with fillers, it lacks the hyperbranched polyester core skeleton unique to hyperbranched interfacial damping modifiers and the hydrophobic long chain / hindered phenol structure capable of providing steric hindrance and entanglement.

[0076] Comparative Example 3

[0077] This comparative example is used to illustrate the case of using a hyperbranched polymer without silane anchoring groups; formulation: 35 parts of polypropylene, 60 parts of barium sulfate, 5 parts of hydroxyl-terminated hyperbranched polyester grafted stearic acid, without silanization reaction in step S13; preparation method: same as example 1; due to the lack of alkoxy silane groups in the modifier, it cannot form chemical bonding with inorganic sound insulation fillers, relying only on physical compatibility.

[0078] Performance testing and effect analysis

[0079] In order to verify the technical effect of the sound insulation carpet material composition of the present application, the materials prepared in the above examples and comparative examples were tested for performance; the test items included: 1. tensile strength (MPa): representing the mechanical load-bearing capacity of the material; 2. elongation at break (%): representing the flexibility of the material, reflecting the quality of interfacial bonding; 3. sound transmission loss (STL, dB): tested at a frequency of 500 Hz, representing the sound insulation performance; 4. loss factor (tan δ): tested by DMA at 25°C, representing the damping energy dissipation capacity of the material; 5. odor grade: tested according to VDA270 standard, 1-6 grade, the lower the grade, the smaller the odor.

[0080] The test results are shown in the following table:

[0081]

[0082] Result analysis:

[0083] Interfacial bonding and mechanical property analysis: comparing example 1 with comparative example 1, it can be seen that after adding the hyperbranched interfacial damping modifier, the tensile strength and elongation at break are greatly improved; in particular, the elongation at break is increased from 40% to 420%, which confirms that the alkoxy silane groups are hydrolyzed in situ during processing and form a firm chemical bond with the surface of barium sulfate, solving the two-skin phenomenon; comparing example 1 with comparative example 3, although comparative example 3 contains a hyperbranched structure, it lacks anchoring units (silane groups), resulting in limited improvement in mechanical properties, indicating that chemical bonding is a key element for improving interfacial strength.

[0084] Damping and sound insulation performance analysis: the loss factor of example 1 is significantly higher than that of comparative example 2; the small molecule coupling agent used in comparative example 2 can improve the interfacial bonding, but due to the short molecular chain, it cannot provide sufficient intramolecular friction; while the modifier of the application has a hyperbranched core + long chain / hindered phenol structure, this bulky flexible structure produces significant viscoelastic loss under the action of sound waves, thereby greatly improving the STL value; example 2 further improves the steric effect by introducing a hindered phenol group, so that it still maintains a very high STL and loss factor under high filling, proving the effectiveness of the structural design;

[0085] Process and application advantages: the odor levels of examples 1-5 are lower, better than comparative example 2 using traditional coupling agents; this is because the hyperbranched interfacial damping modifier has a large molecular weight and does not belong to volatile organic compounds, and due to its low viscosity characteristic of hyperbranched structure, it does not need to add small molecule plasticizer during processing, thereby solving the problem of odor in the car from the source.

[0086] In summary, the sound insulation carpet material composition provided by the application solves the problems of poor mechanical properties, low damping and heavy odor of high filling materials through the special molecular structure design of the hyperbranched interfacial damping modifier, realizing the chemical bonding and physical entanglement of inorganic fillers and organic matrix during in-situ reactive extrusion, and has significant technical progress.

[0087] The above is only the preferred embodiment of the application, and does not limit the application in other forms. Any person skilled in the art can use the disclosed technical content to make changes or modifications to equivalent embodiments applied to other fields, but any simple modification, equivalent change and modification made according to the technical essence of the application to the above embodiments without departing from the technical solution content of the application still belongs to the protection scope of the technical solution of the application.

Claims

1. A sound-insulating carpet material composition, characterized in that, By weight, it includes: 20-50 parts of thermoplastic resin matrix; 40-80 parts of inorganic sound-insulating filler; and 1 to 10 parts of hyperbranched interface damping modifier; Among them, the hyperbranched interface damping modifier has a hyperbranched polyester core skeleton. The terminal hydroxyl portion of the core skeleton is grafted with alkoxysilane groups through urethane bonds, and the remaining portion is grafted with hydrophobic long-chain alkyl or hindered phenolic groups through ester bonds. The alkoxysilane groups can be hydrolyzed during processing and form chemical bonds with the hydroxyl groups on the surface of the inorganic sound insulation filler. The hydrophobic long-chain alkyl or hindered phenolic groups can form physical entanglement or compatibility with the thermoplastic resin matrix.

2. The sound-insulating carpet material composition according to claim 1, characterized in that, The composition comprises, by weight: 25-40 parts of thermoplastic resin matrix; 50-75 parts of inorganic sound-insulating filler; 2-5 parts of hyperbranched interface damping modifier; The thermoplastic resin matrix is ​​selected from at least one of polypropylene, thermoplastic elastomer, or ethylene-vinyl acetate copolymer; The inorganic sound insulation filler is selected from at least one of barium sulfate, calcium carbonate or mica powder, and the particle size of the inorganic sound insulation filler is ≤15μm.

3. The sound-insulating carpet material composition according to claim 1 or 2, characterized in that, The raw materials for preparing hyperbranched interface damping modifiers include: trimethylolpropane, dimethylolpropionic acid, propyltriethoxysilane 3-isocyanate, and long-chain fatty acids or hindered phenolic acids. Among them, the alkoxysilyl group is derived from the addition reaction of 3-propyl isocyanatetriethoxysilane with the terminal hydroxyl group of the core skeleton; Hydrophobic long-chain groups originate from the esterification reaction of long-chain fatty acids with the terminal hydroxyl groups of the core skeleton; hindered phenolic groups originate from the esterification reaction of hindered phenolic acids with the terminal hydroxyl groups of the core skeleton. The long-chain fatty acid is selected from at least one of stearic acid, lauric acid, or palmitic acid.

4. The sound-insulating carpet material composition according to claim 3, characterized in that, The preparation method of the sound-insulating carpet material composition includes: Step S1: Prepare a hyperbranched interface damping modifier; Step S2: The thermoplastic resin matrix, inorganic sound insulation filler and hyperbranched interface damping modifier are premixed to obtain a premix. Step S3: The premixed material is added to a twin-screw extruder and subjected to in-situ reactive extrusion in a molten state. After cooling and granulation, a sound-insulating carpet material composition is obtained.

5. The sound-insulating carpet material composition according to claim 4, characterized in that, Step S1 specifically includes: Step S11, constructing the core framework: Trimethylolpropane and dimethylolpropionic acid are added to the reactor at a molar ratio of 1:10 to 1:

20. Under nitrogen protection and mechanical stirring, the temperature is raised to 130 to 150°C for melt polycondensation reaction. During the reaction, vacuum dehydration is continuously carried out until the acid value of the product drops below 5 mg KOH / g to obtain hydroxyl-terminated hyperbranched polyester. Step S12, introducing a damping unit: add long-chain fatty acids or acids with hindered phenolic structures to the hydroxyl-terminated hyperbranched polyester, carry out an esterification reaction at 140-160°C and under negative pressure, and remove the reaction byproduct water using a condenser or vacuum suction until no water is generated, to obtain an intermediate. Step S13, introducing the anchoring unit: Dissolve the intermediate in anhydrous aprotic polar solvent, cool to 60-80℃, add dibutyltin dilaurate as a catalyst, and add 3-propyltriethoxysilane dropwise under constant pressure. After the addition is complete, keep the reaction at the temperature for 2-4 hours to allow the isocyanate groups to undergo an addition reaction with the remaining hydroxyl groups. After the reaction is complete, remove the solvent by rotary evaporation under reduced pressure or vacuum drying to obtain the hyperbranched interface damping modifier.

6. The sound-insulating carpet material composition according to claim 5, characterized in that, In step S12, the molar ratio of the hydroxyl groups of the hydroxyl-terminated hyperbranched polyester to long-chain fatty acids or carboxylic acids with hindered phenolic structures is 1:0.4 to 0.8; in step S13, the molar ratio of the hydroxyl groups of the hydroxyl-terminated hyperbranched polyester to propyltriethoxysilane 3-isocyanate is 1:0.1 to 0.

4.

7. The sound-insulating carpet material composition according to claim 4, characterized in that, In step S3, the barrel temperature of the twin-screw extruder is set to 140–210°C, and the screw speed is 200–400 rpm. In the closed reaction section, the hydrolysis reaction is initiated by the adsorption of water on the surface of the raw material or by the addition of 0.05–0.5 parts by weight of water. In the vacuum exhaust section, the vacuum degree ≥0.08 MPa is turned on to remove reaction byproducts and small molecule volatiles. During the in-situ reactive extrusion process, the alkoxysilane groups of the hyperbranched interface damping modifier are hydrolyzed under high temperature shear and trace moisture, and undergo a condensation reaction with the hydroxyl groups on the surface of the inorganic sound insulation filler in situ to form a chemically bonded interface.

8. A sound-insulating carpet material, characterized in that, It includes a surface decorative layer and a back coating, wherein the back coating is made of a sound-insulating carpet material composition according to any one of claims 1-7.

9. The sound-insulating carpet material according to claim 8, characterized in that, The thickness of the back coating is 1.5 to 4.0 mm, and the sound transmission loss (STL) of the sound insulation carpet in the frequency range of 100 to 500 Hz is ≥25 dB.

10. The application of the sound-insulating carpet material according to claim 8 or 9 in automotive interiors, characterized in that, It is laid on top of the car chassis sheet metal to block low-frequency vibration noise from the road surface and high-frequency noise from the engine.

Images