Sound insulation and noise reduction automobile foot mat and preparation process thereof

Abstract

The invention relates to the technical field of sound insulation materials, and discloses a sound insulation and noise reduction automobile foot mat and a preparation process thereof. Comprising the following operation steps: step 1, sequentially heating and melting thermoplastic elastomers, injecting the thermoplastic elastomers into a mold, and maintaining the pressure for 15-25 seconds to obtain a base layer; step 2, (1) banburying modified melamine and ethylene propylene diene monomer, adding a foaming agent, a foaming promoter and a vulcanizing agent, and continuously banburying and mixing to obtain a rubber compound; (2) blade-coating the rubber compound on the surface of the base layer, and obtaining a sound absorption layer through a foaming process; step 3: (1) banburying and mixing the sound insulation material for 10-15 minutes, taking out and calendering to obtain a sound insulation layer; (2) coating the surface of the sound absorption layer with a hot melt adhesive, then coating the sound absorption layer with a sound insulation layer, and carrying out hot pressing treatment at 80-90 DEG C for 8-15 minutes to obtain a prefabricated automobile foot mat; and 4, a protective layer is attached to the surface of the prefabricated automobile foot mat in a hot-pressing mode, trimming machining is conducted, and the sound insulation and noise reduction automobile foot mat is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of sound insulation materials, and specifically to a sound insulation and noise reduction automotive floor mat and its preparation process. Background Technique

[0002] Nowadays, the market share of automobiles has been gradually increasing. Many automobile engines are located below the driver's cab, and the radiated noise directly enters the cab through the vehicle body floor and the floor mat. Among them, the medium and high-frequency noise generated by the electric drive system of electric vehicles and the medium and low-frequency noise generated by the friction between the tires and the road surface are more easily perceived by the vehicle occupants, thus seriously affecting the interior noise level and the driving experience of users. At present, the sound absorption performance of the floor mats used in automobiles is acceptable, but the sound insulation performance is poor, so it still affects the comfortable environment inside the vehicle. Therefore, automobile users will choose some automotive floor mats with sound insulation and noise reduction functions as an auxiliary to improve the comfort of the vehicle during driving.

[0003] In summary, it is of great significance to prepare an automotive floor mat with sound insulation and noise reduction functions. Summary of the Invention

[0004] The purpose of the present invention is to provide a sound insulation and noise reduction automotive floor mat and its preparation process to solve the problems raised in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A preparation process for a sound insulation and noise reduction automotive floor mat includes the following operating steps:

[0007] Step 1: Heat and melt polyolefin particles in sequence, inject them into a mold, and keep the pressure for 15 - 25 seconds to obtain a base layer.

[0008] Step 2: (1) Knead modified melamine and ethylene propylene diene monomer rubber at 120 - 125 °C for 10 - 12 minutes, add a foaming agent, a foaming aid, and a vulcanizing agent, and continue to knead and mix for 10 - 20 minutes to obtain a rubber kneaded compound; (2) Scrape and coat the rubber kneaded compound on the surface of the base layer, and obtain a sound absorption layer through a foaming process.

[0009] Step 3: (1) Knead and mix the sound insulation material for 10 - 15 minutes, take it out and calender it to obtain a sound insulation layer; (2) Coat a layer of hot melt adhesive on the surface of the sound absorption layer, cover it with a layer of sound insulation layer, and perform hot pressing treatment at 80 - 90 °C for 8 - 15 minutes to obtain a prefabricated automotive floor mat.

[0010] Step 4: Hot press and bond a protective layer on the surface of the prefabricated automotive floor mat, and trim and process it to obtain a sound insulation and noise reduction automotive floor mat.

[0011] Preferably, the thickness of the base layer is 1 - 2 mm; the thickness of the sound absorption layer is 8 - 12 mm; the thickness of the sound insulation layer is 2 - 5 mm; the thickness of the protective layer is 0.1 - 0.5 mm.

[0012] Preferably, the raw materials of the rubber compound include the following components: by mass, 70 - 75 parts of ethylene propylene diene monomer rubber, 5 - 6 parts of modified melamine, 12 - 15 parts of foaming agent, 3 - 4 parts of foaming aid, 1.5 - 2 parts of vulcanizing agent; the raw materials of the sound insulation material include butyl rubber, modified lignin, and ethylene - vinyl acetate copolymer with a mass ratio of 3:(0.1 - 0.3):(1 - 2).

[0013] Preferably, the raw materials of the polyolefin particles include one or more of polypropylene, polyethylene, and ethylene - octene copolymer; the protective layer is one of TPU film, PET film, and PE film; the hot melt adhesive is EVA hot melt adhesive, and the coating amount is 20 - 30 g / m 2 。

[0014] Preferably, the preparation method of the modified melamine is as follows: (1) Add nano - zinc oxide to an ethanol - aqueous solution, ultrasonically disperse it, heat it to 60 - 70 °C, and dropwise add a silane coupling agent KH570 - ethanol - aqueous solution, react for 1 - 2 hours to obtain modified nano - zinc oxide; (2) Add 4 - hydroxystyrene and trimethylol melamine to deionized water, heat it to 80 - 90 °C, uniformly mix for 1 - 2 hours, add a Lewis catalyst, and react for 1 - 2 hours to obtain vinyl - melamine; (3) Add the modified nano - zinc oxide to toluene and ultrasonically disperse it to obtain a mixed solution; add butadiene, vinyl - melamine, and BPO initiator to toluene and uniformly mix, under a nitrogen atmosphere, heat it to 60 - 70 °C, react for 1 - 2 hours, add the modified nano - zinc oxide and uniformly mix, continue to react for 3 - 5 hours, cool to room temperature, wash, dry, and pulverize to obtain modified melamine.

[0015] Preferably, the mass ratio of the nano - zinc oxide to the silane coupling agent KH570 is 1:(0.2 - 0.5); the molar ratio of 4 - hydroxystyrene to trimethylol melamine is 1:1; the raw materials of the modified melamine include the following components: by mass, 3 - 4 parts of vinyl - melamine, 0.7 - 1.2 parts of butadiene, 0.5 - 0.8 parts of modified nano - zinc oxide, 0.1 - 0.3 parts of BPO initiator, and 20 - 30 parts of toluene.

[0016] Preferably, the preparation method of the modified lignin is as follows: Add silane coupling agent KH570 and silane coupling agent Si69 into an ethanol aqueous solution, mix uniformly to obtain a mixed solution of silane coupling agents; Grind alkali lignin through a 60-120 mesh sieve, add it into the ethanol aqueous solution, disperse it by ultrasonic wave, add the mixed solution of silane coupling agents, react at 60-70 °C for 2-3 hours, wash and dry to obtain the modified lignin.

[0017] Preferably, the silane coupling agent KH570 accounts for 15-20 wt% of the mixed solution of silane coupling agents, and the silane coupling agent Si69 accounts for 5-10 wt% of the mixed solution of silane coupling agents; The mass ratio of the alkali lignin to the mixed solution of silane coupling agents is 1:(2-3).

[0018] Preferably, the temperature of the heating and melting is 200-230 °C; The pressure for injecting into the mold is 70-80 MPa, the temperature of the mold is 30-40 °C, and the pressure for holding pressure is 50-60 MPa; The temperature of the foaming process is 160-180 °C, the pressure is 0.2-0.5 MPa, and the time is 8-12 minutes; In step 3, the temperature of the kneading and mixing is 120-140 °C, and the time is 10-15 minutes; The pressure for hot pressing and laminating is 0.2-0.4 MPa, and the temperature is 60-80 °C.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] In this solution, the sound-insulating and noise-reducing car foot mat mainly includes: a base layer, a sound-absorbing layer, a sound-insulating layer, and a protective layer; Among them, for the sound-absorbing layer, first knead and mix melamine, ethylene propylene diene monomer (EPDM), a foaming agent, a foaming aid, and a vulcanizing agent, and then lay it on the surface of the base layer. Through the foaming process, a sound-absorbing layer with a porous structure is obtained.

[0021] In order to improve the bonding force between the sound-insulating layer and the sound-absorbing layer, in the solution, EVA is used as a hot melt adhesive, which has good compatibility with the EVA part in the sound-insulating layer, thereby improving the bonding force between the two; The base layer is made of a polyolefin material with good compatibility with ethylene propylene diene monomer (EPDM); The protective layer uses a TPU film with waterproof, dustproof and certain wear resistance.

[0022] Among them, melamine itself has a certain sound-absorbing ability. The porous characteristics in its structure can make sound waves continuously reflect and refract in the pores, thereby consuming sound energy; Ethylene propylene diene monomer (EPDM) has elasticity, relatively high hardness and heat resistance, making it not easy to deform and damage; It can make the material vibrate when receiving sound wave impact, further dissipating the sound energy; After the two are combined and foamed, the formed complex porous structure and elastic system can improve the absorption effect on sound waves of different frequencies, effectively reduce the noise inside the vehicle, and improve the quiet and comfortable degree inside the vehicle.

[0023] However, the compatibility between melamine and ethylene propylene diene monomer (EPDM) is poor, which will reduce the effect of the sound absorption layer. Therefore, in the solution, trimethylol melamine and 4-hydroxystyrene are reacted under certain conditions to obtain vinyl-melamine. Then it is copolymerized with butadiene to obtain modified melamine. The modified melamine contains butadiene segments, and these segments are similar to EPDM in structure and properties, and can be better compatible with EPDM. During the mixing process, the two are easy to penetrate and entangle with each other to form a uniform mixing system. During the foaming process, they can also act synergistically to make the foaming structure more stable and uniform, which is beneficial to the improvement of sound absorption performance.

[0024] In order to further improve the effect of the sound absorption layer, in the solution, nano-zinc oxide is introduced into the modified melamine. Nano-zinc oxide has a special crystal structure and surface characteristics, which has a certain scattering and absorption effect on sound waves. In the EPDM foaming system, it also has the functions of vulcanization, reinforcement and compatibility, making the cell structure more uniform and delicate, increasing the propagation path and scattering degree of sound waves inside the material, so as to improve the sound absorption effect.

[0025] In the solution, the sound insulation layer is obtained by mixing butyl rubber, modified lignin and EVA through mixing in an internal mixer, taking out and calendering. It is connected with the sound absorption layer through hot pressing treatment with hot melt adhesive.

[0026] Among them, butyl rubber has good damping characteristics. When sound waves propagate to butyl rubber, the internal friction of its molecular chains will hinder the propagation of sound waves, causing the sound wave energy to decay, thus achieving the effect of sound insulation. Lignin has a porous structure, increasing the propagation path of sound waves inside the material, thereby improving the sound absorption performance of the material and helping to reduce noise. EVA itself has a certain sound insulation performance and good flexibility. The synergistic effect with butyl rubber and modified lignin can further optimize the acoustic performance of the sound insulation layer and improve the sound insulation effect on sound waves of different frequencies.

[0027] In the solution, lignin itself has a certain rigidity and strength. In order to improve the interaction between lignin and butyl rubber and EVA, two different silane coupling agents are introduced on its surface to make it better combine with butyl rubber and EVA, playing a role in sealing and sound insulation, and making the sound insulation layer not easily deformed or damaged when subjected to external forces, ensuring the structural integrity of the sound insulation layer, and then maintaining a good sound insulation effect. Specific Embodiments

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0029] In the following specific embodiments, "parts" refers to parts by mass. In this embodiment, it should be noted that there are no special restrictions on the manufacturers from which the raw materials involved in the present invention are purchased. Exemplarily, they include: the ethylene-octene copolymer has a model number of 8999 and is purchased from Dongguan Yucheng Plastic Co., Ltd.; the ethylene propylene diene monomer rubber has a product number of 3720P and is purchased from Dongguan Nabichuan Plastic Co., Ltd.; the TPU film has a model number of 558300NAT035 and is purchased from Dongguan Suguang Plastic Raw Materials Co., Ltd.; the CAS number of azodicarbonamide (foaming agent) is 123-77-3; the CAS number of zinc stearate (foaming aid) is 557-05-1; the CAS number of sulfur (vulcanizing agent) is 7704-34-9; the product number of the isoprene-isobutyl copolymer (butyl rubber) is JS5002 and is purchased from Hubei Jusheng Technology Co., Ltd.; the EVA (ethylene-vinyl acetate copolymer) has a model number of GB and is purchased from Wuhan Xinxin Jiali Biotechnology Co., Ltd.; the product number of alkali lignin is 471003 and is purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the CAS number of silane coupling agent KH570 is 2530-85-0; the specification of silane coupling agent Si69 is 25KG and is purchased from Jinan Huanzheng Chemical Co., Ltd.; the CAS number of 4-hydroxystyrene is 2628-17-3; the product number of trimethylolmelamine is YK4547 and is purchased from Hubei Yongkuo Technology Co., Ltd.; the product number of nano-zinc oxide is GH60002, with a specification of 90nm, and is purchased from Shanghai Hansi Chemical Co., Ltd.; the CAS number of butadiene is 106-99-0; the CAS number of BPO initiator is 94-36-0.

[0030] The preparation method of modified melamine is as follows: (1) Weigh nano-zinc oxide and silane coupling agent KH570 according to a mass ratio of 1:0.3; add nano-zinc oxide to an ethanol aqueous solution (concentration 75 wt%) and disperse it by ultrasonic wave, heat it to 70 °C, dropwise add the silane coupling agent KH570-ethanol aqueous solution, and react for 2 hours to obtain modified nano-zinc oxide; (2) Weigh 4-hydroxystyrene and trimethylolmelamine according to a molar ratio of 1:1; add 4-hydroxystyrene and trimethylolmelamine to deionized water, heat it to 85 °C and mix evenly for 2 hours, add 0.01 part of Lewis catalyst (aluminum trichloride), and react for 2 hours to obtain vinyl-melamine; (3) Add 0.5 part of modified nano-zinc oxide to 10 parts of toluene and disperse it by ultrasonic wave to obtain a mixed solution; add 1 part of butadiene, 3.2 parts of vinyl-melamine, and 0.02 part of BPO initiator to 20 parts of toluene and mix evenly. Under a nitrogen atmosphere, heat it to 70 °C, react for 2 hours, add the mixed solution, mix evenly, continue to react for 4 hours, cool to room temperature, wash, dry, and pulverize to obtain modified melamine.

[0031] The preparation method of modified lignin is as follows: Add silane coupling agent KH570 and silane coupling agent Si69 into the ethanol aqueous solution, mix evenly to obtain a mixed solution of silane coupling agents; Grind the alkali lignin through an 80-mesh sieve, add it into the ethanol aqueous solution, disperse it ultrasonically, add the mixed solution of silane coupling agents, react at 70 °C for 2 hours, wash, and dry to obtain modified lignin;

[0032] Among them, silane coupling agent KH570 accounts for 15 wt% of the mixed solution of silane coupling agents, and silane coupling agent Si69 accounts for 10 wt% of the mixed solution of silane coupling agents; The mass ratio of the alkali lignin to the mixed solution of silane coupling agents is 1:2.5.

[0033] Example 1: The preparation process of a sound-insulating and noise-reducing automotive floor mat;

[0034] Step 1: Heat and melt the ethylene-octene copolymer at 220 °C, inject it into a mold at 35 °C under a pressure of 70 MPa, and keep the pressure at 55 MPa for 15 seconds to obtain a base layer with a thickness of 1 mm;

[0035] Step 2: (1) Knead 5 parts of modified melamine and 75 parts of ethylene propylene diene monomer (EPDM) at 125 °C for 10 minutes; Add 15 parts of foaming agent, 4 parts of foaming aid, and 1.8 parts of vulcanizing agent, and continue to knead and mix for 13 minutes to obtain a rubber compound; (2) Spread the rubber compound on the surface of the base layer, set the temperature at 172 °C, and foam at a pressure of 0.4 MPa for 10 minutes to obtain a sound-absorbing layer with a thickness of 8 mm;

[0036] Step 3: (1) Weigh butyl rubber, modified lignin, and EVA according to a mass ratio of 3:0.1:1 as the sound-insulating material; Knead and mix the sound-insulating material at 125 °C for 15 minutes, take it out and calender it to obtain a sound-insulating layer with a thickness of 2 mm; (2) Coat the surface of the sound-absorbing layer with hot melt adhesive (EVA hot melt adhesive, coating amount is 25 g / m 2 ) and then cover the sound-insulating layer, and perform hot pressing treatment at 85 °C for 12 minutes to obtain a prefabricated automotive floor mat;

[0037] Step 4: On the surface of the prefabricated automotive floor mat, set the temperature at 80 °C and the pressure at 0.3 MPa to hot press and bond a protective layer (TPU film) with a thickness of 0.3 mm, and then trim and process to obtain a sound-insulating and noise-reducing automotive floor mat.

[0038] Example 2: The preparation process of a sound-insulating and noise-reducing automotive floor mat, including the following operating steps;

[0039] Step 1: Heat and melt the ethylene-octene copolymer at 220 °C, inject it into a mold at 35 °C under a pressure of 70 MPa, and keep the pressure at 55 MPa for 15 seconds to obtain a base layer with a thickness of 2 mm;

[0040] Step 2: (1) Knead 5 parts of modified melamine and 75 parts of ethylene propylene diene monomer (EPDM) at 125°C for 10 minutes; add 15 parts of blowing agent, 4 parts of blowing aid, and 1.8 parts of vulcanizing agent, and continue to knead and mix for 13 minutes to obtain a rubber compound; (2) Spread the rubber compound on the surface of the base layer, set the temperature at 172°C, and foam at a pressure of 0.4 MPa for 10 minutes to obtain a sound-absorbing layer with a thickness of 12 mm;

[0041] Step 3: (1) Weigh butyl rubber, modified lignin, and EVA according to a mass ratio of 3:0.1:1 as the sound insulation material; knead and mix the sound insulation material at 125°C for 15 minutes, take it out and calender it to obtain a sound insulation layer with a thickness of 5 mm; (2) Coat the surface of the sound-absorbing layer with hot melt adhesive (EVA hot melt adhesive, coating amount is 25 g / m 2 ), then cover it with the sound insulation layer, and perform hot pressing treatment at 85°C for 12 minutes to obtain a prefabricated automotive floor mat;

[0042] Step 4: On the surface of the prefabricated automotive floor mat, set the temperature at 80°C and the pressure at 0.3 MPa to hot press and bond a protective layer (TPU film) with a thickness of 0.3 mm, and then trim and process it to obtain a sound-insulating and noise-reducing automotive floor mat.

[0043] Example 3: A preparation process of a sound-insulating and noise-reducing automotive floor mat, including the following operation steps;

[0044] Step 1: Heat and melt ethylene-octene copolymer at 220°C, inject it into a mold at 35°C under a pressure of 70 MPa, and hold the pressure at 55 MPa for 15 seconds to obtain a base layer with a thickness of 1.5 mm;

[0045] Step 2: (1) Knead 5 parts of modified melamine and 75 parts of ethylene propylene diene monomer (EPDM) at 125°C for 10 minutes; add 15 parts of blowing agent, 4 parts of blowing aid, and 1.8 parts of vulcanizing agent, and continue to knead and mix for 13 minutes to obtain a rubber compound; (2) Spread the rubber compound on the surface of the base layer, set the temperature at 172°C, and foam at a pressure of 0.4 MPa for 10 minutes to obtain a sound-absorbing layer with a thickness of 10 mm;

[0046] Step 3: (1) Weigh butyl rubber, modified lignin, and EVA according to a mass ratio of 3:0.1:1 as the sound insulation material; knead and mix the sound insulation material at 125°C for 15 minutes, take it out and calender it to obtain a sound insulation layer with a thickness of 2.5 mm; (2) Coat the surface of the sound-absorbing layer with hot melt adhesive (EVA hot melt adhesive, coating amount is 25 g / m 2 ), then cover it with the sound insulation layer, and perform hot pressing treatment at 85°C for 12 minutes to obtain a prefabricated automotive floor mat;

[0047] Step 4: Set the temperature to 80°C and the pressure to 0.3 MPa on the surface of the prefabricated automotive floor mat, and hot-press and bond a protective layer (TPU film) with a thickness of 0.3 mm, then trim and process to obtain a sound-insulating and noise-reducing automotive floor mat.

[0048] Comparative Example 1 is based on Example 2, the difference being that modified melamine is not added to the rubber compound.

[0049] Step 1: Heat and melt ethylene-octene copolymer at 220°C, inject it into a mold at 35°C under a pressure of 70 MPa, and hold the pressure at 55 MPa for 15 seconds to obtain a base layer with a thickness of 2 mm.

[0050] Step 2: (1) Knead 75 parts of ethylene propylene diene monomer (EPDM) at 125°C for 10 minutes; add 15 parts of foaming agent, 4 parts of foaming aid, and 1.8 parts of vulcanizing agent, and continue to knead and mix for 13 minutes to obtain a rubber compound; (2) Spread the rubber compound on the surface of the base layer, set the temperature to 172°C, and foam at a pressure of 0.4 MPa for 10 minutes to obtain a sound-absorbing layer with a thickness of 12 mm.

[0051] Step 3: (1) Weigh butyl rubber, modified lignin, and EVA according to a mass ratio of 3:0.1:1 as the sound-insulating material; knead and mix the sound-insulating material at 125°C for 15 minutes, take it out and calender to obtain a sound-insulating layer with a thickness of 5 mm; (2) Coat hot melt adhesive (EVA hot melt adhesive, coating amount is 25 g / m 2 ) on the surface of the sound-absorbing layer, then cover the sound-insulating layer, and perform hot-press treatment at 85°C for 12 minutes to obtain a prefabricated automotive floor mat.

[0052] Step 4: Set the temperature to 80°C and the pressure to 0.3 MPa on the surface of the prefabricated automotive floor mat, and hot-press and bond a protective layer (TPU film) with a thickness of 0.3 mm, then trim and process to obtain a sound-insulating and noise-reducing automotive floor mat.

[0053] Comparative Example 2 is based on Example 2, the difference being that in the modified lignin, silane coupling agent Si69 is introduced alone.

[0054] Step 1: Heat and melt ethylene-octene copolymer at 220°C, inject it into a mold at 35°C under a pressure of 70 MPa, and hold the pressure at 55 MPa for 15 seconds to obtain a base layer with a thickness of 2 mm.

[0055] Step 2: (1) Knead 5 parts of modified melamine and 75 parts of ethylene propylene diene monomer (EPDM) at 125°C for 10 minutes; add 15 parts of foaming agent, 4 parts of foaming aid, and 1.8 parts of vulcanizing agent, and continue to knead and mix for 13 minutes to obtain a rubber compound; (2) Spread the rubber compound on the surface of the base layer, set the temperature to 172°C, and foam at a pressure of 0.4 MPa for 10 minutes to obtain a sound-absorbing layer with a thickness of 12 mm.

[0056] Step 3: (1) Add silane coupling agent Si69 into an ethanol aqueous solution, mix evenly to obtain a mixed solution of silane coupling agent; Grind alkali lignin through an 80-mesh sieve, add it into the ethanol aqueous solution, disperse it by ultrasonic wave, add the mixed solution of silane coupling agent, react at 70 °C for 2 hours, wash and dry to obtain modified lignin; The silane coupling agent Si69 accounts for 10 wt% of the mixed solution of silane coupling agent; The mass ratio of alkali lignin to the mixed solution of silane coupling agent is 1:2.5;

[0057] (2) Weigh butyl rubber, modified lignin, and EVA according to a mass ratio of 3:0.1:1 as a sound insulation material; Knead and mix the sound insulation material at 125 °C for 15 minutes, take it out and calender to obtain a sound insulation layer with a thickness of 5 mm; (3) Coat the surface of the sound absorption layer with hot melt adhesive (EVA hot melt adhesive, coating amount is 25 g / m 2 ) and then cover with the sound insulation layer, and perform hot pressing treatment at 85 °C for 12 minutes to obtain a prefabricated automotive foot mat;

[0058] Step 4: On the surface of the prefabricated automotive foot mat, set the temperature at 80 °C and the pressure at 0.3 MPa to hot press and laminate a protective layer (TPU film) with a thickness of 0.3 mm, and trim and process to obtain a sound insulation and noise reduction automotive foot mat.

[0059] Comparative Example 3 is based on Example 2, the difference is that butadiene is not introduced into unmodified melamine;

[0060] Step 1: Heat and melt ethylene-octene copolymer at 220 °C, inject it into a mold at 35 °C under a pressure of 70 MPa, and hold the pressure at 55 MPa for 15 seconds to obtain a base layer with a thickness of 2 mm;

[0061] Step 2: (1) Weigh nano-zinc oxide and silane coupling agent KH570 according to a mass ratio of 1:0.3; Add nano-zinc oxide into an ethanol aqueous solution (concentration 75 wt%) and disperse it by ultrasonic wave, heat up to 70 °C, dropwise add the silane coupling agent KH570-ethanol aqueous solution, and react for 2 hours to obtain modified nano-zinc oxide; (2) Weigh 4-hydroxystyrene and trimethylol melamine according to a molar ratio of 1:1; Add 4-hydroxystyrene and trimethylol melamine into deionized water, heat up to 85 °C and mix evenly for 2 hours, add 0.01 part of Lewis catalyst (aluminum trichloride), and react for 2 hours to obtain vinyl-melamine; (3) Add 0.5 part of modified nano-zinc oxide into 10 parts of toluene and disperse it by ultrasonic wave to obtain a mixed solution; Add 3.2 parts of vinyl-melamine and 0.02 part of BPO initiator into 20 parts of toluene and mix evenly, under a nitrogen atmosphere, heat up to 70 °C, react for 2 hours, add the mixed solution, mix evenly, continue to react for 4 hours, cool to room temperature, wash and dry, and pulverize to obtain modified melamine;

[0062] (4) Knead 5 parts of modified melamine and 75 parts of ethylene propylene diene monomer (EPDM) at 125 °C for 10 minutes; add 15 parts of foaming agent, 4 parts of foaming aid, and 1.8 parts of vulcanizing agent, and continue to knead and mix for 13 minutes to obtain a rubber compound; (5) Scraping and coating the rubber compound on the surface of the base layer, setting the temperature at 172 °C and the pressure at 0.4 MPa for foaming for 10 minutes to obtain a sound-absorbing layer with a thickness of 12 mm;

[0063] Step 3: (1) Weigh butyl rubber, modified lignin, and EVA according to a mass ratio of 3:0.1:1 as the sound insulation material; knead and mix the sound insulation material at 125 °C for 15 minutes, take it out and calender it to obtain a sound insulation layer with a thickness of 5 mm; (2) Coat hot melt adhesive (EVA hot melt adhesive, coating amount is 25 g / m 2 ) on the surface of the sound-absorbing layer, cover the sound insulation layer, and perform hot pressing treatment at 85 °C for 12 minutes to obtain a prefabricated automotive foot mat;

[0064] Step 4: On the surface of the prefabricated automotive foot mat, set the temperature at 80 °C and the pressure at 0.3 MPa for hot pressing and laminating a protective layer (TPU film) with a thickness of 0.3 mm, and trim and process to obtain a sound-insulating and noise-reducing automotive foot mat.

[0065] Comparative Example 4 is based on Example 2, the difference is that modified nano-zinc oxide is not introduced into the modified melamine;

[0066] Step 1: Heat and melt ethylene-octene copolymer at 220 °C, inject it into a mold at 35 °C under a pressure of 70 MPa, and hold the pressure at 55 MPa for 15 seconds to obtain a base layer with a thickness of 2 mm;

[0067] Step 2: (1) Weigh 4-hydroxystyrene and trimethylol melamine according to a molar ratio of 1:1; add 4-hydroxystyrene and trimethylol melamine to deionized water, heat to 85 °C and mix evenly for 2 hours, add 0.01 part of Lewis catalyst (aluminum trichloride), and react for 2 hours to obtain vinyl-melamine; (2) Add 0.5 part of modified nano-zinc oxide to 10 parts of toluene and disperse it by ultrasonic wave to obtain a mixed solution; add 1 part of butadiene, 3.2 parts of vinyl-melamine, and 0.02 part of BPO initiator to 20 parts of toluene and mix evenly, under a nitrogen atmosphere, heat to 70 °C, react for 6 hours, cool to room temperature, wash, dry, and pulverize to obtain modified melamine;

[0068] (3) Knead 5 parts of modified melamine and 75 parts of ethylene propylene diene monomer (EPDM) at 125 °C for 10 minutes; add 15 parts of blowing agent, 4 parts of blowing aid, and 1.8 parts of vulcanizing agent, and continue to knead and mix for 13 minutes to obtain a rubber compound; (4) Spread the rubber compound on the surface of the base layer, set the temperature at 172 °C, and foam at a pressure of 0.4 MPa for 10 minutes to obtain a sound-absorbing layer with a thickness of 12 mm;

[0069] Step 3: (1) Weigh butyl rubber, modified lignin, and EVA according to a mass ratio of 3:0.1:1 as the sound insulation material; knead and mix the sound insulation material at 125 °C for 15 minutes, take it out and calender to obtain a sound insulation layer with a thickness of 5 mm; (2) Coat the surface of the sound-absorbing layer with hot melt adhesive (EVA hot melt adhesive, coating amount is 25 g / m 2 ), then cover with the sound insulation layer, and perform hot pressing treatment at 85 °C for 12 minutes to obtain a prefabricated automotive foot mat;

[0070] Step 4: On the surface of the prefabricated automotive foot mat, set the temperature at 80 °C and the pressure at 0.3 MPa to hot press and bond a protective layer (TPU film) with a thickness of 0.3 mm, and trim and process to obtain a sound-insulating and noise-reducing automotive foot mat.

[0071] Detection test: Detect the vehicles equipped with Examples 1-3 and Comparative Examples 1-4 during actual vehicle road tests at a constant speed of 120 km / h on the test track road surface, and respectively detect the sound pressure levels (dB) at the driver's position in the vehicle under low-frequency noise of 400 Hz and high-frequency noise of 1500 Hz.

[0072]

[0073]

[0074] Table 1

[0075] Comparative Example 1 is based on Example 2, the difference is that modified melamine is not added to the rubber compound; resulting in a decline in the performance of the sound-insulating and noise-reducing automotive foot mat; Comparative Example 2 is based on Example 2, the difference is that in the modified lignin, silane coupling agent Si69 is introduced alone; the impact on the sound-insulating and noise-reducing automotive foot mat is relatively small; Comparative Example 3 is based on Example 2, the difference is that butadiene is introduced into the unmodified melamine; resulting in a decrease in the compatibility between the modified melamine and EPDM, thus leading to a decline in the performance of the sound-insulating and noise-reducing automotive foot mat; Comparative Example 4 is based on Example 2, the difference is that modified nano-zinc oxide is not introduced into the modified melamine; because nano-zinc oxide has a certain scattering and absorption effect on sound waves; in the EPDM foaming system, it makes the cell structure more uniform and delicate, thus leading to a decline in the performance of the sound-insulating and noise-reducing automotive foot mat in Comparative Example 4.

[0076] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, in all respects, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention.

Claims

1. A preparation process for a sound-insulating and noise-reducing car floor mat, characterized in that: It includes the following operation steps: Step 1: Heat and melt the polyolefin particles in sequence, inject them into a mold, and keep the pressure for 15 - 25 seconds to obtain a base layer; Step 2: (1) Knead the modified melamine and ethylene propylene diene monomer (EPDM) at 120 - 125 °C for 10 - 12 minutes, add a blowing agent, a blowing aid, and a vulcanizing agent, and continue to knead and mix for 10 - 20 minutes to obtain a rubber compound; (2) Scrape and coat the rubber compound on the surface of the base layer, and obtain a sound-absorbing layer through a foaming process; Step 3: (1) Knead and mix the sound insulation material for 10 - 15 minutes, take it out and calender it to obtain a sound insulation layer; (2) Coat a layer of hot melt adhesive on the surface of the sound-absorbing layer, cover it with a layer of sound insulation layer, and perform hot pressing treatment at 80 - 90 °C for 8 - 15 minutes to obtain a prefabricated automotive foot mat; Step 4: Thermally press and bond a protective layer on the surface of the prefabricated automotive foot mat, and trim and process it to obtain an automotive foot mat with sound insulation and noise reduction.

2. The preparation process of a sound-insulating and noise-reducing car floor mat according to claim 1, characterized in that: The thickness of the base layer is 1 - 2 mm; the thickness of the sound-absorbing layer is 8 - 12 mm; the thickness of the sound insulation layer is 2 - 5 mm; the thickness of the protective layer is 0.1 - 0.5 mm.

3. The preparation process of a sound-insulating and noise-reducing car floor mat according to claim 1, characterized in that: The raw materials of the rubber compound include the following components: by mass, 70 - 75 parts of ethylene propylene diene monomer (EPDM), 5 - 6 parts of modified melamine, 12 - 15 parts of blowing agent, 3 - 4 parts of blowing aid, 1.5 - 2 parts of vulcanizing agent; the raw materials of the sound insulation material include butyl rubber, modified lignin, and ethylene vinyl acetate copolymer with a mass ratio of 3:(0.1 - 0.3):(1 - 2).

4. The preparation process of a sound-insulating and noise-reducing car floor mat according to claim 1, characterized in that: The raw materials of the polyolefin particles include one or more of polypropylene, polyethylene, and ethylene-octene copolymer; the protective layer is one of TPU film, PET film, and PE film; the hot melt adhesive is EVA hot melt adhesive, and the coating amount is 20-30 g / m 2 .

5. The preparation process of a sound-insulating and noise-reducing car floor mat according to claim 1, characterized in that: The preparation method of the modified melamine is: (1) Add nano-zinc oxide to an ethanol aqueous solution and disperse it by ultrasonic wave, heat it up to 60 - 70 °C, dropwise add a silane coupling agent KH570-ethanol aqueous solution, and react for 1 - 2 hours to obtain modified nano-zinc oxide; (2) Add 4-hydroxystyrene and trimethylol melamine to deionized water, heat it up to 80 - 90 °C and mix evenly for 1 - 2 hours, add a Lewis catalyst, and react for 1 - 2 hours to obtain vinyl-melamine; (3) Add the modified nano-zinc oxide to toluene and disperse it by ultrasonic wave to obtain a mixed solution; add butadiene, vinyl-melamine, and a BPO initiator to toluene and mix evenly, under a nitrogen atmosphere, heat it up to 60 - 70 °C, react for 1 - 2 hours, add the modified nano-zinc oxide and mix evenly, continue to react for 3 - 5 hours, cool it to room temperature, wash, dry, and crush it to obtain the modified melamine.

6. The preparation process of a sound-insulating and noise-reducing automotive floor mat according to claim 5, characterized in that: The mass ratio of the nano-zinc oxide to the silane coupling agent KH570 is 1:(0.2 - 0.5); the molar ratio of the 4-hydroxystyrene to the trimethylol melamine is 1:1; the raw materials of the modified melamine include the following components: by mass, 3 - 4 parts of vinyl-melamine, 0.7 - 1.2 parts of butadiene, 0.5 - 0.8 parts of modified nano-zinc oxide, 0.1 - 0.3 parts of BPO initiator, and 20 - 30 parts of toluene.

7. The preparation process of a sound-insulating and noise-reducing automotive floor mat according to claim 3, characterized in that: The preparation method of the modified lignin is as follows: Add silane coupling agent KH570 and silane coupling agent Si69 into an ethanol aqueous solution, and mix evenly to obtain a mixed solution of silane coupling agents; Grind the alkali lignin through a 60-120 mesh sieve, add it into the ethanol aqueous solution, disperse it by ultrasonic wave, add the mixed solution of silane coupling agents, react at 60-70 °C for 2-3 hours, wash and dry to obtain the modified lignin.

8. The preparation process of a sound-insulating and noise-reducing automotive floor mat according to claim 7, characterized in that: The silane coupling agent KH570 accounts for 15-20 wt% of the mixed solution of silane coupling agents, and the silane coupling agent Si69 accounts for 5-10 wt% of the mixed solution of silane coupling agents; The mass ratio of the alkali lignin to the mixed solution of silane coupling agents is 1:(2-3).

9. The preparation process of a sound-insulating and noise-reducing car foot mat according to claim 1, characterized in that: The temperature of the heating and melting is 200-230 °C; The pressure for injecting into the mold is 70-80 MPa, the temperature of the mold is 30-40 °C, and the pressure for holding the pressure is 50-60 MPa; The temperature of the foaming process is 160-180 °C, the pressure is 0.2-0.5 MPa, and the time is 8-12 minutes; In step 3, the temperature of the internal mixer mixing is 120-140 °C, and the time is 10-15 minutes; The pressure of the hot pressing and laminating is 0.2-0.4 MPa, and the temperature is 60-80 °C.

10. A sound-insulating and noise-reducing car foot mat is prepared by the preparation process of the sound-insulating and noise-reducing car foot mat according to any one of claims 1-9.

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