Automotive interior carpet and preparation method thereof

Abstract

The invention discloses an automobile interior carpet and a preparation method thereof, and relates to the technical field of automobile interiors, the automobile interior carpet comprises a backing layer, the backing layer is prepared from a thermoplastic elastomer composition, and the thermoplastic elastomer composition comprises the following components in parts by weight: 20-50 parts of thermoplastic elastomer matrix resin; 10 to 30 parts of plasticizing oil; 0.5 to 10 parts of a functionalized star cyclodextrin modifier; 20-60 parts of an inorganic filler; the functionalized star cyclodextrin modifier has a core-shell structure, and takes beta-cyclodextrin or a beta-cyclodextrin derivative as a core and a grafted polyacrylate flexible polymer chain as a shell. By introducing the modifier with a core-shell structure, adsorbing high-temperature volatile matters by utilizing a cavity of the core structure, and dissipating vibration energy in cooperation with the movement of the flexible chain segment of the shell layer, the synergistic effect of low odor, low VOC emission and excellent damping performance is realized, the problem that environmental protection and sound insulation of a traditional carpet are difficult to consider at the same time is solved, and the driving and riding comfort is improved.

Description

Technical Field

[0001] This invention relates to the field of automotive interior technology, specifically to an automotive interior carpet and its preparation method. Background Technology

[0002] Currently, the backing layer of automotive interior carpets is mainly constructed using thermoplastic elastomer materials. By physically blending the base resin, plasticizer oil, and inorganic fillers, and then molding it through extrusion and calendering processes, it is finally laminated with the surface layer to achieve coverage and sound insulation of the bottom of the car interior. Under normal usage scenarios, this material system based on physical blending can meet the basic mechanical support and shielding functions, and is the mainstream solution in current automotive interior manufacturing.

[0003] However, with increasing consumer demands for in-vehicle air quality and quietness, elastomer carpet systems based on single physical blends have revealed a series of problems in related technologies. At high temperatures, the small molecular components within the material are prone to intensified thermal motion, leading to increased release of volatile organic compounds and unpleasant odors inside the vehicle. Simultaneously, the damping energy dissipation capacity of existing materials often fails to remain stable across a wide temperature range. Faced with the complex mechanical vibrations generated by vehicle operation, the materials struggle to effectively convert and dissipate vibration energy, limiting their sound insulation and noise reduction effects. Furthermore, small molecule additives added to improve processing performance pose a risk of migrating to the surface during long-term use, causing the material surface to become sticky or foggy. Current technologies struggle to balance low odor, high damping, and long-term stability, necessitating significant improvements. Summary of the Invention

[0004] The purpose of this invention is to provide an automotive interior carpet and its preparation method, thereby solving the problems existing in the background art.

[0005] To address the aforementioned technical problems, the present invention provides an automotive interior carpet, comprising a backing layer made of a thermoplastic elastomer composition, wherein the thermoplastic elastomer composition comprises the following components by weight: (A) 20-50 parts of thermoplastic elastomer matrix resin; (B) 10-30 parts of plasticizer oil; (C) 0.5–10 parts of functionalized star-shaped cyclodextrin modifier; (D) 20-60 parts of inorganic filler; the functionalized star-shaped cyclodextrin modifier has a core-shell structure, with β-cyclodextrin or β-cyclodextrin derivatives as the core and grafted polyacrylate flexible polymer chains as the shell; the preparation process of the functionalized star-shaped cyclodextrin modifier includes: (i) Esterification modification: β-cyclodextrin was dissolved in an aprotic polar solvent, and esterification reaction was carried out by adding a haloacylation reagent dropwise in the presence of an acid-binding agent at low temperature. After post-treatment, a multifunctional macromolecular initiator was obtained. (ii) Graft polymerization: Multifunctional macromolecular initiators, acrylate monomers, transition metal catalysts and ligands are dissolved in an organic solvent. The mass ratio of monomers to solvent is controlled. After deoxygenation, an atom transfer radical polymerization reaction is initiated under heating conditions, so that flexible polymer chains grow in situ on the surface of cyclodextrin. After the reaction is completed, the functionalized star-shaped cyclodextrin modifier is obtained by quenching, purification and drying.

[0006] Preferably, the preparation step of the multifunctional macromolecular initiator in step (i) is as follows: β-cyclodextrin, which has been vacuum dried, is dissolved in N,N-dimethylacetamide or N,N-dimethylformamide, and an acid-binding agent, triethylamine or pyridine, is added. The system is ultrasonically vibrated to obtain a clear solution. The reaction system is placed in an ice-water bath at 0–5°C, and 2-bromo-2-methylpropionyl bromide is slowly added dropwise through a constant-pressure dropping funnel under magnetic stirring and nitrogen protection, with the addition time controlled to be completed within 1–2 hours. After the addition is completed, the ice-water bath is removed, and the system is allowed to naturally warm to room temperature and continue... The reaction was stirred for 12–24 hours. After the reaction was completed, the reaction solution was concentrated to 20%–30% of its original volume by rotary evaporation at 40–50°C. The concentrate was then poured into 10–20 times its volume of ice water or methanol / water mixed solvent to precipitate the solid. The solid was collected by filtration and washed 2–3 times with anhydrous ethanol. Finally, it was dried to constant weight in a vacuum oven at 40–50°C to obtain the multifunctional macromolecular initiator CD-Br. The molar ratio of β-cyclodextrin, 2-bromo-2-methylpropionyl bromide and the acid-binding agent was 1:(18–25):(18–25).

[0007] Preferably, the graft polymerization step in step (ii) specifically involves: sequentially adding the multifunctional macromolecular initiator CD-Br obtained in step (i), n-butyl acrylate monomer, ligand pentamethyldiethylenetriamine, and solvent anisole to a reaction vessel; ultrasonically dispersing for 3–5 minutes to homogenize the system, wherein the mass ratio of n-butyl acrylate monomer to solvent anisole is 1:(0.5–2.0); adding the catalyst cuprous bromide to the system; immediately sealing the reaction vessel; performing a freeze-evacuation-thawing cycle 3–5 times to completely remove dissolved oxygen from the system; subsequently, placing the reaction system in a constant temperature oil bath at 60–80°C under inert gas protection; and magnetically stirring and polymerizing for 6–12 hours; after the polymerization reaction is completed, ... The reaction flask was rapidly cooled in liquid nitrogen or ice water to terminate the reaction. Tetrahydrofuran was added to dilute the reaction solution, and the solution was filtered through a neutral alumina chromatography column to adsorb and remove the copper salt catalyst. The filtrate after column chromatography was concentrated by rotary evaporation. The concentrate was added dropwise to excess cold methanol to precipitate the precipitate. After standing and separating the layers, the upper clear liquid was discarded, and the lower viscous substance was dried under vacuum at 40-60°C to obtain a star polymer with polybutyl acrylate as the arm, i.e., a functionalized star cyclodextrin modifier. The molar ratio of the initiating group in the multifunctional macromolecular initiator CD-Br, the polybutyl acrylate monomer, the catalyst cuprous bromide, and the ligand pentamethyldiethylenetriamine was 1:(50-200):(0.5-1.5):(0.5-1.5).

[0008] Preferably, the thermoplastic elastomer matrix resin is selected from one or more of styrene-ethylene / butene-styrene block copolymer, styrene-ethylene / propylene-styrene block copolymer, or thermoplastic polyolefin; the inorganic filler is selected from one or more of calcium carbonate, talc, barium sulfate, or wollastonite, and the particle size of the inorganic filler is 13-18 μm.

[0009] Preferably, the polymer chain ends of the functionalized star-shaped cyclodextrin modifier are further introduced with a compatible anchoring segment. This introduction step is carried out when the atom transfer radical polymerization reaction reaches a monomer conversion rate of 80% to 90%, by adding a second monomer, glycidyl methacrylate or dodecyl methacrylate, to the reaction system, and continuing the reaction at a constant temperature of 60 to 80°C for 1 to 3 hours, so that the polymer chain ends undergo block copolymerization to generate end-group structures containing epoxy groups or long-chain alkyl groups.

[0010] A method for preparing automotive interior carpet is also provided, characterized by comprising the following steps: (1) Premixing: The thermoplastic elastomer matrix resin, plasticizer oil, functionalized star cyclodextrin modifier and inorganic filler are put into a high-speed mixer according to the formula amount. The mixture is stirred at high speed of 500-800 rpm for 3-5 minutes. The plasticizer oil is fully impregnated with the resin and filler by frictional heat to obtain a dry and flowing premix. (2) Melt extrusion: The premixed material is added to the main feed port of the twin-screw extruder and melt-blended under the shearing and conveying action of the screw; the barrel temperature of the extruder is set to gradient heating, with a temperature range of 160℃~210℃ from the feeding section to the die head, and the screw speed is 200~400rpm. A vacuum devolatilization device is installed in the exhaust section of the extruder, and the vacuum degree is controlled at -0.06MPa~-0.08MPa to remove volatile small molecules. (3) Calendering: The melt extruded from the extruder head is directly fed into a three-roll calender. The roller temperature is controlled at 60-80℃. After calendering, densification, cooling and shaping, it is cut to obtain the backing layer of the automotive interior carpet. (4) Composite: The backing layer is combined with the tufted carpet surface or non-woven fabric surface layer through flame bonding or hot melt adhesive bonding process to obtain the finished car interior carpet.

[0011] Compared with the prior art, the present invention has the following beneficial effects: By constructing a special micro-encapsulation structure in the thermoplastic elastomer matrix, and utilizing the unique cavity effect of this structure as a molecular trap, it is possible to effectively adsorb and lock in small molecules that may be free in the matrix resin and plasticizing system. This restricts the free diffusion and escape of volatile components under heating conditions, blocking the odor generation path at the source and ensuring that the material maintains an extremely low gas emission level even in high-temperature environments, thereby ensuring a healthy and clean air environment inside the vehicle.

[0012] The introduced flexible polymer segments exhibit high elasticity at room temperature. When excited by external mechanical vibration, these segments can generate internal friction through internal micro-movements, efficiently converting mechanical energy into heat energy and dissipating it. This gives the carpet backing excellent damping and shock absorption characteristics, enabling it to effectively isolate low-frequency noise transmitted from the chassis and road vibrations. Furthermore, it has good interfacial compatibility, avoiding mechanical property degradation caused by phase separation and ensuring the toughness and fatigue resistance of the material during use.

[0013] The dispersion state of inorganic fillers in organic matrix is ​​improved, forming a multi-dimensional physical network structure. This not only enhances the overall mechanical strength of the material, but also further improves the sound wave energy loss efficiency through the internal friction of network nodes. The material system exhibits suitable fluidity during processing and excellent anti-migration ability after molding. It achieves a good balance between processability and finished product performance, overcoming the contradiction between environmental protection indicators and acoustic performance that is difficult to achieve with traditional materials. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a comparative analysis chart of VOC emission levels according to the present invention. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0016] To verify the technical effect of the automotive interior carpet and its preparation method of the present invention, the present invention will be further described in detail below with reference to specific embodiments. The present invention solves the contradiction between VOC release and insufficient damping performance of traditional TPE carpets at high temperatures by introducing a special modifier with a core-shell structure at the microscopic molecular level. The following embodiments are intended to demonstrate the specific effects of different component ratios and process parameters on the performance of the final product within the scope defined by the claims. Example 1

[0017] This embodiment provides an automotive interior carpet, including a backing layer made of a thermoplastic elastomer composition. By weight, the thermoplastic elastomer composition comprises the following components: (A) 35 parts of a styrene-ethylene / butene-styrene block copolymer as the thermoplastic elastomer matrix resin; (B) 20 parts of naphthenic oil as a plasticizing oil; (C) 5 parts of a functionalized star-shaped cyclodextrin modifier; and (D) 40 parts of calcium carbonate with a particle size of 15 μm as an inorganic filler. The functionalized star-shaped cyclodextrin modifier has a core-shell structure, with β-cyclodextrin as the core and grafted polyacrylate flexible polymer chains as the shell. The preparation process of the functionalized star-shaped cyclodextrin modifier strictly follows the steps defined in the claims: (i) in the esterification modification stage, β-cyclodextrin that has been vacuum dried is dissolved in N,N-dimethylacetamide, and triethylamine, an acid-binding agent, is added. The mixture is ultrasonically vibrated to obtain a clear solution. The reaction system is placed in an ice-water bath at 0°C, and 2-bromo-2-methylpropionyl bromide is added dropwise under nitrogen protection. The dropwise addition time is controlled at 1.5 hours. Then, the mixture is naturally heated to room temperature and stirred for 18 hours. After concentration, precipitation, washing and drying, a multifunctional macromolecular initiator CD-Br is obtained, wherein the molar ratio of β-cyclodextrin, 2-bromo-2-methylpropionyl bromide and the acid-binding agent is set to 1:21:21; (ii) in the graft polymerization stage, in the reaction volume... The multifunctional macromolecular initiator CD-Br, n-butyl acrylate monomer, pentamethyldiethylenetriamine ligand, and anisole solvent were added to the reactor, wherein the mass ratio of n-butyl acrylate monomer to anisole solvent was 1:1; cuprous bromide catalyst was added, and after deoxygenation through a freeze-evacuation-thawing cycle, the reaction was carried out in a constant temperature oil bath at 70°C for 8 hours; wherein the molar ratio of initiating group, monomer, catalyst, and ligand was 1:100:1:1; when the atom transfer radical polymerization reaction reached a monomer conversion rate of 85%, a second monomer, glycidyl methacrylate, was added to the reaction system, and the reaction was continued for 2 hours to introduce an epoxy group anchoring segment; the final product was purified and dried to obtain a functionalized star-shaped cyclodextrin modifier; The preparation method of the car interior carpet includes: (1) mixing the above components in a high-speed mixer at 600 rpm for 4 minutes; (2) feeding the premix into a twin-screw extruder, setting the barrel temperature gradient to 160°C to 210°C, the screw speed to 300 rpm, and the vacuum degree to -0.07 MPa; (3) calendering the extruded melt into shape using a 70°C three-roll calender; and (4) hot-melt bonding it with a tufted carpet surface. The automotive interior carpet prepared in this embodiment utilizes the β-cyclodextrin cavity structure of the functionalized star-shaped cyclodextrin modifier, which can effectively adsorb small molecule volatiles released by the matrix resin and plasticizer oil at high temperatures. At the same time, the grafted flexible long chain of n-butyl acrylate is in a highly elastic state at room temperature, dissipating vibrational energy through chain segment movement. Due to the introduction of glycidyl methacrylate as an anchoring segment, the compatibility between the modifier and the SEBS matrix is ​​improved, avoiding the decrease in mechanical properties caused by phase separation. Example 2

[0018] This embodiment provides an automotive interior carpet, including a backing layer made of a thermoplastic elastomer composition. By weight, the thermoplastic elastomer composition comprises the following components: (A) 50 parts of styrene-ethylene / propylene-styrene block copolymer (SEPS) as the thermoplastic elastomer matrix resin; (B) 30 parts of paraffin oil as the plasticizer; (C) 10 parts of functionalized star-shaped cyclodextrin modifier; and (D) 20 parts of talc with a particle size of 13 μm as an inorganic filler. The preparation process of the functionalized star-shaped cyclodextrin modifier is as follows: (i) In the esterification modification, N,N-dimethylformamide is selected as the solvent and pyridine is selected as the acid-binding agent. The reaction temperature is controlled at 5℃ and the reaction is carried out at room temperature for 24 hours. The molar ratio of β-cyclodextrin, 2-bromo-2-methylpropionyl bromide and acid-binding agent is 1:25:25 to obtain a highly substituted, multifunctional macromolecular initiator CD-Br; (ii) In the graft polymerization, the mass ratio of n-butyl acrylate monomer to anisole solvent is 1:2.0, the polymerization temperature is 80℃, and the reaction time is 12 hours. The molar ratio of initiating group, monomer, catalyst, and ligand is 1:200:1.5:1.5 to grow longer polymer arms. When the monomer conversion rate reaches 90%, the second monomer, dodecyl methacrylate, is added, and the reaction continues for 3 hours to enhance the physical entanglement with the high-oil-content matrix using long-chain alkyl groups. In the preparation process, the premixing speed is adjusted to 800 rpm for 5 minutes; the extruder screw speed is 400 rpm, and the vacuum degree is -0.08 MPa to address potential volatiles from the high oil content; the calender roll temperature is 80℃. This embodiment aims to maximize the carpet's VOC adsorption capacity and damping effect by increasing the content of functionalized star-shaped cyclodextrin modifier to 10 parts and combining it with a long-chain structure with high grafting density. The long-chain polybutyl acrylate arms provide a larger free volume and friction sites, enabling the carpet to exhibit excellent shock absorption and noise reduction performance over a wide temperature range, making it particularly suitable for luxury vehicles with high requirements for quietness.

[0019] Example 3 This example provides an automotive interior carpet, including a backing layer. The backing layer is prepared from a thermoplastic elastomer composition, which, by weight, comprises the following components: (A) 20 parts of thermoplastic polyolefin (TPO) as the thermoplastic elastomer matrix resin; (B) 10 parts of naphthenic oil as the plasticizing oil; (C) 0.5 parts of functionalized star-shaped cyclodextrin modifier; (D) 60 parts of barium sulfate with a particle size of 18 μm as an inorganic filler. The preparation process of the functionalized star-shaped cyclodextrin modifier is as follows: (i) In the esterification modification, the molar ratio of β-cyclodextrin, 2-bromo-2-methylpropionyl bromide and acid-binding agent is 1:18:18, and the reaction is carried out at room temperature for 12 hours; (ii) In the graft polymerization, the mass ratio of n-butyl acrylate monomer to solvent anisole is 1:0.5, the polymerization temperature is 60℃, and the reaction time is 6 hours; the molar ratio of initiating group, monomer, catalyst and ligand is 1:50:0.5:0.5; when the monomer conversion rate is 80%, glycidyl methacrylate is added for end-capping reaction for 1 hour; in the preparation process, the premixing speed is 500 rpm and the mixing time is 3 minutes; the extruder screw speed is 200 rpm and the vacuum degree is -0.06 MPa; the calender roll temperature is 60℃; This embodiment demonstrates a technical solution under conditions of high filler content and low modifier content. Although the amount of functionalized star-shaped cyclodextrin modifier added is low, its unique star-shaped topology can still play a role similar to that of an interface modifier, improving the dispersibility of high proportion of inorganic fillers in the TPO matrix. At the same time, by utilizing the high density characteristics of barium sulfate in combination with the molecular damping of the modifier, basic acoustic isolation performance is maintained while reducing costs, making it suitable for interior carpet applications in economy vehicles.

[0020] Example 4 This example provides an automotive interior carpet, including a backing layer made of a thermoplastic elastomer composition. By weight, the thermoplastic elastomer composition includes the following components: (A) 40 parts of a mixture of SEBS and TPO (mass ratio 1:1) as the thermoplastic elastomer matrix resin; (B) 25 parts of plasticizing oil; (C) 8 parts of a functionalized star-shaped cyclodextrin modifier; and (D) 30 parts of wollastonite as an inorganic filler. The preparation process of the functionalized star-shaped cyclodextrin modifier is as follows: (i) the esterification modification parameters are set to a molar ratio of β-cyclodextrin, 2-bromo-2-methylpropionyl bromide and acid-binding agent of 1:22:22; (ii) in the graft polymerization, the polymerization temperature is 75℃ and the reaction time is 10 hours; the molar ratio of initiating group, monomer, catalyst and ligand is 1:150:1.2:1.2; when the monomer conversion rate is 88%, dodecyl methacrylate is added and reacted for 1.5 hours; the preparation process parameters are between those of Example 1 and Example 2, and the highest extrusion temperature is 200℃; This embodiment uses a mixed resin matrix, utilizing the polyacrylate arms and dodecyl methacrylate end groups on the outer layer of the functionalized star-shaped cyclodextrin modifier to effectively compatibilize the interface between the SEBS and TPO phases. The needle-like structure of wollastonite and the spherical structure of the star-shaped modifier form a multi-dimensional physical network in the matrix, which not only improves the tensile strength of the material, but also further dissipates sound wave energy through the internal friction of the network nodes, achieving a synergistic improvement in mechanical and acoustic properties.

[0021] Example 5 This example provides an automotive interior carpet, including a backing layer made of a thermoplastic elastomer composition. By weight, the thermoplastic elastomer composition includes the following components: (A) 45 parts of SEBS; (B) 15 parts of plasticizing oil; (C) 3 parts of functionalized star-shaped cyclodextrin modifier; (D) 37 parts of calcium carbonate. The preparation process of the functionalized star-shaped cyclodextrin modifier is as follows: (i) esterification modification molar ratio 1:20:20; (ii) in the graft polymerization, the molar ratio of initiating group, monomer, catalyst and ligand is 1:80:0.8:0.8, the polymerization temperature is 65℃, and the reaction time is 9 hours; glycidyl methacrylate is added at a conversion rate of 82% and reacted for 2.5 hours; the preparation process is carried out in accordance with the scope of claim 6. This embodiment aims to verify the comprehensive performance under a medium ratio; the functionalized star-shaped cyclodextrin modifier, with an addition of 3 parts, is able to form an effective VOC capture network; by controlling the degree of polymerization (monomer ratio 1:80), the modifier arm length is moderate, which not only ensures dispersion and flowability in the matrix and prevents excessive viscosity during processing, but also provides sufficient flexible segments for damping energy dissipation; this formulation achieves a good balance between processing flowability, odor level and production cost.

[0022] Comparative Example 1 provides a conventional thermoplastic elastomer carpet with a formulation that is basically the same as that of Example 1, except that: no functionalized star-shaped cyclodextrin modifier is added, but an equal amount (5 parts) of ordinary unmodified β-cyclodextrin powder is added directly; the preparation process is the same as that of Example 1.

[0023] Comparative Example 2 provides a modified carpet with a formulation that is essentially the same as that of Example 1, except that an equal amount (5 parts) of linear n-butyl polyacrylate is used instead of the functionalized star-shaped cyclodextrin modifier. This comparative example aims to examine the performance differences in the absence of the cyclodextrin core structure.

[0024] To objectively evaluate the performance of the automotive interior carpet of the present invention, the carpet backing materials prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests. The test standards are as follows: 1. VOC content test: The emission of benzene, toluene, and formaldehyde (μg / g) was tested using the VDA278 standard; 2. Odor rating: The odor rating was determined by a professional odor evaluation team using the VDA270C3 standard (80℃, 2 hours) (Level 1: Odorless - Level 6: Unbearable); 3. Damping performance: The loss factor (tanδ) was tested at 25℃ and 10Hz using a dynamic thermomechanical analyzer (DMA); 4. Tensile properties: The elongation at break (%) was tested using the ASTM D412 standard.

[0025] The test results are summarized in the table below: The comparative analysis of the above tables and experimental data shows that: Examples 1 to 5 all exhibited significantly better low VOC characteristics and high damping performance than the comparative examples; in particular, Example 2, due to the presence of more functionalized star-shaped cyclodextrin modifier and a longer flexible polymer arm, had the lowest VOC content, an odor level of 2.0, and a loss factor as high as 0.42, indicating that the core structure of the modifier effectively locked in small molecule volatiles, while the shell structure effectively converted mechanical vibration energy. Compared with Comparative Example 1, after adding the functionalized star-shaped cyclodextrin modifier, the VOC content in Example 1 decreased by orders of magnitude, and the elongation at break increased from 350% to 650%. This indicates that directly adding unmodified β-cyclodextrin, due to its poor compatibility with the organic matrix, not only makes it difficult to disperse evenly and exert its adsorption effect, but also becomes a stress concentration point, causing the material to become brittle. In contrast, the star-shaped modifier of the present invention achieves molecular-level fusion of the adsorbent and the matrix through in-situ grafting technology, taking into account both deodorization and toughening. Compared with Comparative Example 2, Example 1 showed significantly better VOC removal performance, indicating that although linear polyacrylate can provide a certain damping effect, it lacks the cavity structure of cyclodextrin and cannot actively capture harmful small molecules. In addition, the star-shaped topology has lower viscosity and better anti-migration properties in the melt compared with the linear structure, which helps to maintain the long-term stability of material properties. In summary, the automotive interior carpet and its preparation method of the present invention, by constructing a functionalized star-shaped cyclodextrin modifier with a core-shell structure, cleverly combines the encapsulation function of cyclodextrin with the viscoelasticity and compatibility of polyacrylate, effectively solving the technical problems of strong odor and poor sound insulation in automotive interior carpets without sacrificing mechanical strength, and has good prospects for industrial application.

[0026] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A car interior carpet, characterized in that, Includes a backing layer, which is prepared from a thermoplastic elastomer composition, which, by weight, comprises the following components: (A) 20-50 parts of thermoplastic elastomer matrix resin; (B) 10-30 parts of plasticizer oil; (C) 0.5–10 parts of functionalized star-shaped cyclodextrin modifier; (D) 20-60 parts of inorganic filler; the functionalized star-shaped cyclodextrin modifier has a core-shell structure, with β-cyclodextrin or β-cyclodextrin derivatives as the core and grafted polyacrylate flexible polymer chains as the shell. The preparation process of functionalized star-shaped cyclodextrin modifiers includes: (i) Esterification modification: β-cyclodextrin was dissolved in an aprotic polar solvent, and esterification reaction was carried out by adding a haloacylation reagent dropwise in the presence of an acid-binding agent at low temperature. After post-treatment, a multifunctional macromolecular initiator was obtained. (ii) Graft polymerization: Multifunctional macromolecular initiators, acrylate monomers, transition metal catalysts and ligands are dissolved in an organic solvent. The mass ratio of monomers to solvent is controlled. After deoxygenation, an atom transfer radical polymerization reaction is initiated under heating conditions, so that flexible polymer chains grow in situ on the surface of cyclodextrin. After the reaction is completed, the functionalized star-shaped cyclodextrin modifier is obtained by quenching, purification and drying.

2. The automotive interior carpet according to claim 1, characterized in that, The preparation steps of the multifunctional macromolecular initiator in step (i) are as follows: β-cyclodextrin, which has been vacuum dried, is dissolved in N,N-dimethylacetamide or N,N-dimethylformamide, and triethylamine or pyridine, an acid-binding agent, is added. The system is ultrasonically vibrated to obtain a clear solution. The reaction system is placed in an ice-water bath at 0–5°C. Under magnetic stirring and nitrogen protection, 2-bromo-2-methylpropionyl bromide is slowly added dropwise through a constant-pressure dropping funnel, and the addition time is controlled to be completed within 1–2 hours. After the addition is completed, the ice-water bath is removed, and the mixture is allowed to naturally warm to room temperature while stirring continues. The reaction was carried out for 12–24 hours. After the reaction was completed, the reaction solution was concentrated to 20%–30% of its original volume by rotary evaporation at 40–50 °C. The concentrate was then poured into 10–20 times its volume of ice water or methanol / water mixed solvent to precipitate the solid. The solid was collected by filtration and washed 2–3 times with anhydrous ethanol. Finally, it was dried to constant weight in a vacuum oven at 40–50 °C to obtain the multifunctional macromolecular initiator CD-Br. The molar ratio of β-cyclodextrin, 2-bromo-2-methylpropionyl bromide and the acid-binding agent was 1:(18–25):(18–25).

3. The automotive interior carpet according to claim 2, characterized in that, The graft polymerization step in step (ii) is as follows: The multifunctional macromolecular initiator CD-Br, n-butyl acrylate monomer, ligand pentamethyldiethylenetriamine, and solvent anisole are added sequentially to the reaction vessel. The mixture is ultrasonically dispersed for 3–5 minutes to homogenize the system, wherein the mass ratio of n-butyl acrylate monomer to anisole is 1:(0.5–2.0). Cuprous bromide catalyst is added to the system, and the reaction vessel is immediately sealed. A freeze-evacuation-thawing cycle is performed 3–5 times to completely remove dissolved oxygen from the system. Subsequently, the reaction system is placed in a constant-temperature oil bath at 60–80°C under inert gas protection and polymerized with magnetic stirring for 6–12 hours. After the polymerization reaction is complete, the reaction vessel is... The reaction was terminated by rapidly cooling the bottle in liquid nitrogen or ice water. Tetrahydrofuran was added to dilute the reaction solution, and the solution was filtered through a neutral alumina chromatography column to adsorb and remove the copper salt catalyst. The filtrate after column chromatography was concentrated by rotary evaporation. The concentrate was added dropwise to excess cold methanol to precipitate the product. After standing and separating the layers, the upper clear liquid was discarded, and the lower viscous substance was dried under vacuum at 40-60°C to obtain a star polymer with polybutyl acrylate as the arm, i.e., a functionalized star cyclodextrin modifier. The molar ratio of the initiating group in the multifunctional macromolecular initiator CD-Br, the polybutyl acrylate monomer, the catalyst cuprous bromide, and the ligand pentamethyldiethylenetriamine was 1:(50-200):(0.5-1.5):(0.5-1.5).

4. The automotive interior carpet according to claim 1, characterized in that, The thermoplastic elastomer matrix resin is selected from one or more of styrene-ethylene / butene-styrene block copolymer, styrene-ethylene / propylene-styrene block copolymer, or thermoplastic polyolefin; the inorganic filler is selected from one or more of calcium carbonate, talc, barium sulfate, or wollastonite, and the particle size of the inorganic filler is 13-18 μm.

5. The automotive interior carpet according to claim 1, characterized in that, The polymer chain ends of the functionalized star-shaped cyclodextrin modifier are also introduced with a compatibility anchoring segment. This introduction step is to add a second monomer, glycidyl methacrylate or dodecyl methacrylate, to the reaction system when the monomer conversion rate reaches 80% to 90% in the atom transfer radical polymerization reaction, and continue to react at a constant temperature of 60 to 80°C for 1 to 3 hours, so that the polymer chain ends undergo block copolymerization to generate end-group structures containing epoxy groups or long-chain alkyl groups.

6. A method for preparing an automotive interior carpet according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Premixing: The thermoplastic elastomer matrix resin, plasticizer oil, functionalized star cyclodextrin modifier and inorganic filler are put into a high-speed mixer according to the formula amount. The mixture is stirred at high speed of 500-800 rpm for 3-5 minutes. The plasticizer oil is fully impregnated with the resin and filler by frictional heat to obtain a dry and flowing premix. (2) Melt extrusion: The premixed material is added to the main feed port of the twin-screw extruder and melt-blended under the shearing and conveying action of the screw; the barrel temperature of the extruder is set to gradient heating, with a temperature range of 160℃~210℃ from the feeding section to the die head, and the screw speed is 200~400rpm. A vacuum devolatilization device is installed in the exhaust section of the extruder, and the vacuum degree is controlled at -0.06MPa~-0.08MPa to remove volatile small molecules. (3) Calendering: The melt extruded from the extruder head is directly fed into a three-roll calender. The roller temperature is controlled at 60-80℃. After calendering, densification, cooling and shaping, it is cut to obtain the backing layer of the automotive interior carpet. (4) Composite: The backing layer is combined with the tufted carpet surface or non-woven fabric surface layer through flame bonding or hot melt adhesive bonding process to obtain the finished car interior carpet.

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