Automobile sound insulation pad and preparation method thereof

Abstract

The present application relates to the technical field of sound insulation materials, in particular to a car sound insulation pad and a preparation method thereof. A car sound insulation pad comprises a sound insulation layer and a sound absorption layer, wherein the sound insulation layer comprises: 10-20 parts of a first TPU particle, 10-20 parts of a second TPU particle, 70-120 parts of a filler, 1-2 parts of a coupling agent, 5-10 parts of a plasticizer, 2-5 parts of carbon black, 1-2 parts of an antioxidant, and 1-2 parts of a lubricant; the density of the first TPU particle is 1.2-1.3 g / cm 3 , hardness 50-60 SHD; second TPU particle density 1.2-1.3g / cm 3 , hardness 60‑80 SHA; the sound-absorbing layer is a PU foam layer. PU has a similar structure to TPU and can be foamed directly on TPU without the need for pretreatment steps such as flame treatment and plasma treatment, making the treatment process simple. The resulting sound insulation pad is made of the same material (polyurethane) and can be recycled and reused as a whole, reducing resource waste and environmental pollution.

Description

Technical Field

[0001] The present application relates to the technical field of sound insulation materials, and in particular to an automobile sound insulation pad and a preparation method thereof. Background Art

[0002] The car sound insulation pad is composed of a skin layer and a PU foam layer or fiber cotton, wherein the skin layer plays a role of sound insulation, and the PU foam layer or fiber cotton plays a role of sound absorption. At present, the skin layer is mainly made of vinyl elastomer material with high barium sulfate filling. Its processing technology is to first obtain the skin layer by injection molding or vacuum forming, then pre-treat the skin layer, and finally perform PU foaming on the skin layer. Vinyl elastomer materials have a strong odor, high volatile amount of toxic and harmful organic matter, and are not recyclable. In addition, the sound absorption layer and the sound insulation layer are made of different materials, so it is very difficult to recycle them separately.

[0003] At present, the pretreatment of the surface layer includes flame treatment and plasma treatment. The applicant believes that both flame treatment and plasma treatment require special processing equipment, which is expensive, the processing process is complicated, and the bonding force between the surface layer and the PU layer is poor, which affects the service life of the sound insulation pad. Summary of the invention

[0004] In order to simplify the steps of preparing sound insulation materials and increase the service life of sound insulation pads, the present application provides a car sound insulation pad and a preparation method thereof.

[0005] In a first aspect, the present application provides a car sound insulation pad, which adopts the following technical solution.

[0006] A car sound insulation pad, comprising a sound insulation layer and a sound absorption layer, wherein the sound insulation layer comprises the following raw materials in parts by weight: 10-20 parts of first TPU particles, 10-20 parts of second TPU particles, 70-120 parts of filler, 1-2 parts of coupling agent, 5-10 parts of plasticizer, 2-5 parts of carbon black, 1-2 parts of antioxidant, and 1-2 parts of lubricant;

[0007] The first TPU particle density is 1.2-1.3 g / cm 3 , hardness 50-60 SHD;

[0008] The second TPU particle density is 1.2-1.3 g / cm 3 , hardness 60-80 SHA;

[0009] The sound absorbing layer is a PU foaming layer.

[0010] By adopting the above technical solution, TPU particles are used as the matrix of the sound insulation layer material. TPU and PU have similar structures. PU can be directly foamed on the sound insulation layer made of TPU, without the need for pretreatment steps such as flame treatment and plasma treatment. The treatment process is simple. In addition, the sound insulation layer and the sound absorption layer have strong adhesion and are not prone to delamination.

[0011] Among them, two TPU particles with different density and hardness are compounded, wherein the first TPU particles are plastic phase, which increases hardness and fluidity, and the second TPU particles are rubber phase, which increases toughness and ensures the mechanical properties of the sound insulation layer.

[0012] Finally, the sound insulation material obtained is made of the same material (polyurethane) and can be recycled and reused as a whole, reducing resource waste and environmental pollution.

[0013] Furthermore, the weight ratio of the first TPU particles to the second TPU particles is 1:1.

[0014] Furthermore, the filler is one or more of barium sulfate and calcium carbonate.

[0015] Furthermore, the filler is a microcapsule filler, and the preparation method thereof is as follows:

[0016] 1) Dissolving gelatin and gum arabic in deionized water to form a gelatin solution and a gum arabic solution respectively;

[0017] 2) mixing the gelatin solution and the gum arabic solution to obtain a mixed solution, and dispersing the filler into the mixed solution to obtain a reaction solution;

[0018] 3) Add a pH adjuster to the reaction solution until the pH value of the reaction solution is 3.8-4.2, and then react at 10-20°C for 40-50 minutes;

[0019] 4) After the reaction is completed, the system temperature is lowered to 5-10°C and maintained for 40-50 minutes to solidify and form microcapsules;

[0020] 5) Centrifuge, wash and dry to obtain microencapsulated filler.

[0021] By adopting the above technical scheme, the filler is modified by microencapsulation using gelatin and gum arabic as the wall material to obtain a microcapsule filler. In the processing of the sound insulation layer, the microcapsules can play a lubricating role. Since the surface of the microcapsules is relatively smooth, they can reduce the friction between the materials in the material matrix. For example, when the composite material is pushed forward in the screw of the injection molding machine, the microcapsules can make the material flow smoother, reduce the resistance in the processing process, reduce the energy consumption of the processing equipment, and also help to improve the molding quality of the product.

[0022] Microcapsule fillers can play a role similar to "microspheres" in the sound insulation layer. When the material is impacted by external forces, the microcapsules can absorb and disperse energy. Microcapsule fillers have a certain elasticity. Under the action of impact force, the microcapsules will deform. This deformation can buffer external forces and reduce stress concentration, thereby enhancing the toughness of TPU composite materials. In addition, the elastic effect of microcapsule fillers allows the microcapsule fillers to partially fill these shrinkage spaces when the matrix of the sound insulation layer material shrinks during cooling or curing, thereby reducing the overall shrinkage of the material and improving the stability of the product size.

[0023] In terms of sound insulation, microcapsule fillers have a certain microstructure. When sound waves propagate to the microcapsule area, the wall material and internal space of the microcapsule can scatter and reflect the sound, change the propagation direction of the sound, and gradually disperse the sound energy during the propagation process, thereby reducing the sound propagation intensity to a certain extent. In addition, gelatin and gum arabic both have a certain viscoelasticity. When sound acts on the microcapsule, the wall material will deform and vibrate due to the pressure of the sound wave. In this process, the viscoelasticity of the wall material will cause part of the sound energy to be converted into heat energy and dissipated, achieving a sound-absorbing effect.

[0024] Furthermore, the weight ratio of gelatin to gum arabic is 1:(1-2).

[0025] Furthermore, the weight ratio of the gelatin to gum arabic and to the filler is (1-3):1.

[0026] Furthermore, the gelatin is modified gelatin, and the modification method is as follows:

[0027] Under the protection of protective gas, polybutyl acrylate is added to the gelatin solution under stirring, and then an initiator, ethanol and a buffer are added to build a reaction system, and the temperature of the reaction system is controlled at 60-80°C for reaction for 3-5 hours;

[0028] After the reaction is completed, reduced pressure distillation, dialysis and freeze drying are carried out to obtain modified gelatin.

[0029] By adopting the above technical solution, polybutyl acrylate is grafted onto gelatin to improve the elasticity of gelatin and further improve the mechanical and sound insulation properties of the microcapsule filler.

[0030] Furthermore, the weight ratio of polybutyl acrylate to gelatin is (2-4):10.

[0031] In a second aspect, the present application provides a method for preparing a car sound insulation pad, using the following technical solution.

[0032] A method for preparing a car sound insulation pad comprises the following steps:

[0033] S1. Sound insulation layer processing

[0034] i. Mix the first TPU particles, the second TPU particles, the filler, the coupling agent, the plasticizer, the carbon black, the antioxidant, and the lubricant according to the ratio, and then extrude and mold to obtain a sound insulation layer material;

[0035] ii. forming the sound insulation layer material on a mold by vacuum forming or injection molding to obtain a sound insulation layer;

[0036] S2. Sound absorbing layer processing

[0037] i. Place the sound insulation layer obtained in S1 in a foaming mold,

[0038] ii. Inject PU foaming raw materials for foaming;

[0039] iii. Remove the finished product from the mold.

[0040] Furthermore, the sound insulation material obtained is in granular or sheet form; the granular sound insulation material is formed by injection molding to obtain a sound insulation layer, and the sheet sound insulation material is formed by vacuum forming to obtain a sound insulation layer.

[0041] By adopting the above technical scheme, the preparation method of the present application directly performs PU foaming on the sound insulation layer to obtain the sound absorption layer, without the need for pretreatment steps such as flame treatment and plasma treatment, and the treatment process is simple.

[0042] In summary, this application has the following beneficial effects:

[0043] Two TPU particles with different densities and hardness are compounded as the base of the sound insulation layer material, wherein the first TPU particles are hardened and the second TPU particles are toughened to ensure the mechanical properties of the sound insulation layer. TPU and PU have similar structures. PU can be directly foamed on the sound insulation layer made of TPU without the need for pretreatment steps such as flame treatment and plasma treatment, and the treatment process is simple. In addition, the sound insulation layer and the sound absorbing layer have strong adhesion and are not prone to stratification. The sound insulation material obtained is made of the same material (polyurethane) and can be recycled and reused as a whole, reducing resource waste and environmental pollution. DETAILED DESCRIPTION

[0044] The present application is further described in detail below with reference to the embodiments.

[0045] Raw materials and intermediate preparation examples

[0046] raw material

[0047] The raw materials in the examples of this application can be obtained from the market:

[0048] Coupling agent, KH550;

[0049] Plasticizer, paraffin oil;

[0050] Antioxidant, antioxidant 1010;

[0051] Lubricant, stearic acid;

[0052] Gelatin, technical grade;

[0053] Gum Arabic, technical grade;

[0054] Polybutyl acrylate, purity 99%;

[0055] Initiator, azobisisobutyronitrile;

[0056] Ethanol, analytical grade;

[0057] Buffer, phosphate buffered saline.

[0058] Preparation Example

[0059] Preparation Example 1

[0060] A modified gelatin, the preparation method of which is as follows:

[0061] 1) At 50°C, dissolve 1 kg of gelatin in water to obtain a 3% gelatin solution, and continue stirring to make the gelatin solution uniform;

[0062] 2) Nitrogen was introduced into the gelatin solution for protection. Under stirring, 0.2 kg of polybutyl acrylate was added to the gelatin solution, followed by 0.005 kg of azobisisobutyronitrile initiator and 0.001 kg of ethanol. A buffer was added to adjust the pH value to 8, and a reaction system was built. The temperature of the reaction system was controlled at 70 °C for 4 hours.

[0063] 3) The reaction product was cooled to room temperature and the solvent was removed by vacuum distillation, and then dialyzed in a dialysis bag for 36 hours. Finally, the dialyzed product was freeze-dried at -45°C and a vacuum degree of 5 Pa for 24 hours to obtain modified gelatin.

[0064] Preparation Example 2

[0065] The difference from Preparation Example 1 is that the amount of polybutyl acrylate in Preparation Example 2 is 0.4 kg.

[0066] Preparation Example 3

[0067] Different from Preparation Example 1, the amount of polybutyl acrylate in Preparation Example 3 is 0.6 kg.

[0068] Preparation Example 4

[0069] A microcapsule filler, the preparation method of which is as follows:

[0070] 1) At 50°C, dissolve 1.5 kg of gelatin in water to obtain a 3% gelatin solution, and continue stirring to make the gelatin solution uniform;

[0071] At 50°C, 1.5 kg of gum arabic was dissolved in water to obtain a 3% gum arabic solution, and the solution was stirred continuously to make it uniform.

[0072] 2) mixing the gelatin solution and the gum arabic solution to obtain a mixed solution, and dispersing 3 kg of barium sulfate filler into the mixed solution to obtain a reaction solution;

[0073] 3) Add a pH adjuster to the reaction solution to make the pH value of the reaction solution 4, and then react in an environment of 15°C for 45 minutes;

[0074] 4) After the reaction is completed, the system temperature is lowered to 8°C and maintained for 45 minutes to solidify and form microcapsules;

[0075] 5) After centrifugation, the mixture was washed with deionized water for three times and then vacuum dried at 45°C to a constant weight to obtain microcapsule filler.

[0076] Preparation Example 5

[0077] Different from Preparation Example 4, the total weight of gelatin and gum arabic in Preparation Example 5 is 3 kg, and the weight ratio of gelatin to gum arabic is 1:2.

[0078] Preparation Example 6

[0079] Different from Preparation Example 4, the total weight of gelatin and gum arabic in Preparation Example 6 is 3 kg, and the weight ratio of gelatin to gum arabic is 2:1.

[0080] Preparation Example 7

[0081] Different from Preparation Example 4, the amount of barium sulfate filler in Preparation Example 7 is 1 kg.

[0082] Preparation Examples 8-10

[0083] Different from Preparation Example 2, in Preparation Examples 8-10, the gelatin was replaced by an equal amount of modified gelatin from Preparation Examples 1-3, respectively. Example

[0084] Examples 1-3

[0085] A car sound insulation pad, the preparation method of which is as follows:

[0086] S1. Sound insulation layer processing

[0087] i. The first TPU particles, the second TPU particles, the filler, the coupling agent, the plasticizer, the carbon black, the antioxidant, and the lubricant are mixed according to the ratio in Table 1, and then extruded and granulated to obtain a sound insulation layer material at an extrusion temperature of 190°C;

[0088] ii. The sound insulation layer material is molded on the mold by an injection molding process to obtain a sound insulation layer; the injection mold temperature is 50°C and the injection molding machine screw temperature is 200°C;

[0089] S2. Sound absorbing layer processing

[0090] i. The sound insulation layer obtained by S1 is placed in a foaming mold;

[0091] ii. Inject PU foaming raw materials for foaming;

[0092] iii. Remove the finished product from the mold.

[0093] Table 1 Raw material ratio table of Examples 1-3 (kg)

[0094]

[0095] The first TPU particle density is 1.2g / cm 3 , hardness 55SHD; second TPU particle density 1.3g / cm 3 , hardness 70SHA, filler is barium sulfate.

[0096] Embodiment 4-10

[0097] Different from Example 2, in Examples 4-10, the fillers were replaced by the microcapsule fillers of Preparation Examples 4-10 in equal amounts.

[0098] Embodiment 11

[0099] Different from Example 1, in Example 11:

[0100] S1. Sound insulation layer processing

[0101] i. The first TPU particles, the second TPU particles, the filler, the coupling agent, the plasticizer, the carbon black, the antioxidant, and the lubricant are mixed according to the ratio in Table 1, and then extruded and pressed to obtain a sound insulation layer material at an extrusion temperature of 190°C;

[0102] ii. Preheat the sound insulation sheet in a preheating furnace, set the preheating furnace temperature to 185°C, and preheat the time to 1 minute;

[0103] iii. Place the preheated sheet on a blister mold and set the temperature of the blister mold to 45°C to obtain a sound insulation layer;

[0104] S2. Sound absorbing layer processing

[0105] Same as Example 1.

[0106] Comparative Example

[0107] Comparative Example 1

[0108] Different from Example 1, in Comparative Example 1, an equal amount of first TPU particles are used to replace the second TPU particles.

[0109] Comparative Example 2

[0110] Different from Example 1, in Comparative Example 2, the first TPU particles were replaced by an equal amount of second TPU particles.

[0111] Performance Testing

[0112] Sound insulation layer tensile strength test: tested with a tensile testing machine, the tensile speed is 60mm / min, the results are shown in Table 2.

[0113] Test of the interlayer adhesion between the sound insulation layer and the sound absorption layer: Use a peel strength tester for testing. Fix the sample on the tester to ensure that the bonding interface between the surface sound insulation layer and the sound absorption layer is perpendicular to the direction of tension. Apply tension at a constant speed (100mm / min) until the surface layer and the foaming layer are completely separated. Record the maximum force value reached during the separation process, which is the peel strength. If the bonding force between the sound insulation layer and the sound absorption layer is strong, the sound absorption layer will rupture. The results are shown in Table 2.

[0114] Sound insulation performance test: According to GB / T 18696.-2019 "Measurement of sound absorption coefficient and acoustic impedance in acoustic impedance tubes", the sound transmission loss of the sound insulation material was tested. The thickness of the sound insulation material test sample was 2 mm. The results are shown in Table 2.

[0115] Table 2 Performance test results

[0116]

[0117] Combining Examples 1-10 with Comparative Examples 1-2 and Table 2, it can be seen that the mechanical properties and sound insulation properties of the sound insulation materials obtained in Examples 1-10 are better than those of Comparative Examples 1-2, especially the mechanical properties, which indicates that the sound insulation material obtained in the present application has better comprehensive performance in terms of mechanical properties and sound insulation properties.

[0118] Combining Example 1 with Comparative Examples 1-2 and Table 2, it can be seen that in Example 1, two TPUs with different densities and hardnesses are compounded, and in Comparative Examples 1 and 2, single TPU particles are used. It can be seen that the tensile strength of the sound insulation material obtained in Example 1 is better than that of Comparative Examples 1-2, which indicates that two TPU particles with different densities and hardnesses are compounded as the matrix of the sound insulation layer material, wherein the first TPU particles are hardened and the second TPU particles are toughened, thereby ensuring the mechanical properties of the sound insulation layer.

[0119] In combination with Examples 1-3 and Table 2, it can be seen that the filler content will affect the sound insulation performance of the sound insulation material. The more filler content, the better the sound insulation performance of the sound insulation material. However, it can also be seen that as the filler content increases, the mechanical properties of the sound insulation material will deteriorate. This may be because there are too many fillers, the interface bonding between the filler and the material matrix deteriorates, resulting in the deterioration of the overall mechanical properties of the material.

[0120] Combining Example 2 with Example 4-10 and Table 2, it can be seen that the tensile strength, peel strength and sound insulation effect of the sound insulation material obtained in Example 4-10 are better than those in Example 2, which shows that the use of gelatin and gum arabic as wall materials to microencapsulate the filler can further improve the comprehensive performance of the mechanical properties and sound insulation effect of the sound insulation material. This may be because in terms of mechanical properties, the microcapsule filler can play a role similar to "microspheres" in the sound insulation layer. When the material is impacted by external forces, the microcapsules can absorb and disperse energy. The microcapsule filler has a certain elasticity. Under the action of impact force, the microcapsule will deform. This deformation can buffer external forces and reduce stress concentration, thereby enhancing the toughness of the TPU composite material. In terms of sound insulation effect, the microcapsule filler has a certain microstructure. When the sound wave propagates to the microcapsule area, the wall material and internal space of the microcapsule can scatter and reflect the sound, change the propagation direction of the sound, and gradually disperse the sound energy during the propagation process, thereby reducing the sound propagation intensity to a certain extent. In addition, gelatin and gum arabic have a certain degree of viscoelasticity. When sound acts on the microcapsules, the wall material will deform and vibrate due to the pressure of the sound waves. In this process, the viscoelasticity of the wall material will convert part of the sound energy into heat energy and dissipate it, achieving a sound-absorbing effect.

[0121] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A car sound insulation pad, comprising a sound insulation layer and a sound absorption layer, characterized in that: The sound insulation layer comprises the following raw materials in parts by weight: 10-20 parts of first TPU particles, 10-20 parts of second TPU particles, 70-120 parts of filler, 1-2 parts of coupling agent, 5-10 parts of plasticizer, 2-5 parts of carbon black, 1-2 parts of antioxidant, and 1-2 parts of lubricant; The first TPU particle density is 1.2-1.3 g / cm 3 , hardness 50-60 SHD; The second TPU particle density is 1.2-1.3 g / cm 3 , hardness 60-80 SHA; The sound absorbing layer is a PU foam layer; The filler is a microcapsule filler, and the preparation method thereof is as follows: 1) Dissolve gelatin and gum arabic in deionized water to form a gelatin solution and a gum arabic solution respectively; 2) mixing the gelatin solution and the gum arabic solution to obtain a mixed solution, and dispersing the filler into the mixed solution to obtain a reaction solution; 3) Add a pH adjuster to the reaction solution to make the pH value of the reaction solution 3.8-4.2, and then react at 10-20°C for 40-50 minutes; 4) After the reaction is completed, the system temperature is lowered to 5-10°C and maintained for 40-50 minutes to solidify and form microcapsules; Centrifugation, washing and drying to obtain microcapsule filler; The gelatin is modified gelatin, and the modification method is as follows: Under the protection of protective gas, polybutyl acrylate is added to the gelatin solution under stirring, and then azobisisobutyronitrile initiator, ethanol and phosphate buffer are added, the pH value is adjusted to 8, a reaction system is built, and the temperature of the reaction system is controlled at 60-80°C for reaction for 3-5 hours; After the reaction is completed, reduced pressure distillation, dialysis and freeze drying are carried out to obtain modified gelatin.

2. The car sound insulation pad according to claim 1, characterized in that: The weight ratio of the first TPU particles to the second TPU particles is 1:

1.

3. The car sound insulation pad according to claim 1, characterized in that: The filler is one or more of barium sulfate and calcium carbonate.

4. The automobile sound insulation pad according to claim 1, characterized in that: The weight ratio of gelatin to gum arabic is 1:(1-2).

5. The automobile sound insulation pad according to claim 1, characterized in that: The weight ratio of the gelatin to gum arabic and to the filler is (1-3):

1.

6. The automobile sound insulation pad according to claim 1, characterized in that: The weight ratio of polybutyl acrylate to gelatin is (2-4):

10.

7. A method for preparing a car sound insulation pad as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Sound insulation layer processing i. Mix the first TPU particles, the second TPU particles, the filler, the coupling agent, the plasticizer, the carbon black, the antioxidant, and the lubricant according to the ratio, and then extrude and mold to obtain a sound insulation layer material; ii. forming the sound insulation layer material on a mold by vacuum forming or injection molding to obtain a sound insulation layer; S2. Sound absorbing layer processing i. Place the sound insulation layer obtained in S1 in a foaming mold, ii. Inject PU foaming raw materials for foaming; iii. Remove the finished product from the mold.

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