CN111976247B - Composite material sound insulation pad, and preparation method and application thereof - Google Patents

Composite material sound insulation pad, and preparation method and application thereof Download PDF

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Publication number
CN111976247B
CN111976247B CN201910424854.5A CN201910424854A CN111976247B CN 111976247 B CN111976247 B CN 111976247B CN 201910424854 A CN201910424854 A CN 201910424854A CN 111976247 B CN111976247 B CN 111976247B
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sound
layer
sound insulation
foaming
composite
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CN111976247A (en
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刘晓军
王懿
徐杰
王蕾
李怡璞
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SAIC Motor Corp Ltd
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SAIC Motor Corp Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
    • B32B3/02—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by features of form at particular places, e.g. in edge regions
    • B32B3/08—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by features of form at particular places, e.g. in edge regions characterised by added members at particular parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/06—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the heating method
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/10—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/10—Properties of the layers or laminate having particular acoustical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/10—Properties of the layers or laminate having particular acoustical properties
    • B32B2307/102—Insulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2605/00—Vehicles
    • B32B2605/08—Cars

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)

Abstract

The invention provides a composite material sound insulation pad, a preparation method and application thereof, wherein the sound insulation pad comprises the following components: the sound insulation layer and the composite sound absorption layer are thermally compounded on one surface of the sound insulation layer; the non-boundary area of the composite sound absorption layer is a sound absorption cotton layer, and the boundary area of the composite sound absorption layer is a polymer foaming layer for composite edge sealing. Compare in traditional sound insulation pad, this application sound insulation pad puigging's key region for inhaling the cotton cover of sound, can greatly promote sound insulation pad's sound-absorbing capacity, have better absorption to new energy automobile's high frequency sound to reduce noise reverberation time in the car. Simultaneously, this application give sound insulation and fill up with polymer foaming layer banding, guaranteed that give sound insulation and fill up the accurate and stable of thickness size of hot composite boundary department like key punchhole department to guarantee the cooperation of giving sound insulation and filling up with peripheral part, especially X to the interference value, can promote whole car front bulkhead in give sound insulation and fill up inhale the sound insulation ability, do benefit to the application.

Description

Composite material sound insulation pad, and preparation method and application thereof
Technical Field
The invention relates to the technical field of design and manufacture of automobile NVH acoustic package parts, in particular to a composite material sound insulation pad, and a preparation method and application thereof.
Background
In the automobile front wall plate, the sound insulation pad is arranged on the inner side of a metal plate between an engine compartment and a passenger compartment and is an important NVH (Noise, vibration, harshness) acoustic package part for isolating engine compartment Noise. The part is generally formed by compounding a sound insulation layer and a sound absorption layer, and forms a double-layer wall sound insulation structure with a metal plate. The sound insulation layer is generally made of high-density EVA (ethylene vinyl acetate) sheet or hard cotton felt material, which is also called as heavy layer; the sound-absorbing layer is made of low-density PU (polyurethane) foam material or loose sound-absorbing cotton. A large amount of sound absorption test data show that the sound absorption performance of the sound absorption cotton is obviously higher than that of the low-density PU foam material. In addition, the sound-absorbing cotton has obvious advantages in the aspect of processing high-frequency squeaking of the motor. Therefore, the sound-absorbing cotton material is generally regarded and widely applied in the design and manufacturing process of the automobile sound-insulating pad by virtue of the excellent sound-absorbing performance.
The sound insulation pad in the automobile front wall plate is a part with a complex three-dimensional shape curved surface, wherein the sound insulation layer can be conveniently formed through a hot pressing process or a vacuum adsorption forming process, but the sound insulation cotton is difficult to form. In order to maintain the sound-absorbing property of the sound-absorbing cotton, the sound-absorbing cotton must be kept fluffy, so the sound-absorbing cotton itself has little rigidity, and its molding must be attached to the soundproof layer. At present, two manufacturing methods are used for forming the sound insulation pad by compounding the sound insulation layer and the sound absorption cotton, and only the key points of the two processes are summarized below.
The first method is to fix the sound-absorbing cotton to the sound-insulating layer by adopting a manual installation method; the process mainly comprises 3 steps: 1. forming a sound insulation layer; 2. blanking sound-absorbing cotton; 3. and manually compounding the sound insulation layer obtained in the last two steps and the sound absorption cotton semi-finished product. During compounding, the outer contours of the two layers of materials and all hole sites in the middle need to be aligned and overlapped together, and then the two layers of materials are fixed together at the edges of the outer contours and the hole sites in a manual glue spraying mode, or a manual ultrasonic welding gun or a manual nail gun mode. For the manufacture of the front-wall sound insulation pad as an example, the circumference of the outer contour of the part is about 5m, dozens of hole positions are arranged on the part, and nearly hundreds of composite fixing points need to be arranged manually in the composite process. Therefore, the method of manual composite installation has the fatal defect of extremely low production efficiency. With the great increase of the sales volume of new energy vehicles and the like in recent years, the process is no longer suitable for fast-paced mass production and is gradually eliminated.
The second is a thermal compounding process currently replacing the first process described above; the sound-absorbing cotton boundary is compounded to the sound-insulating layer by adopting a hot edge sealing die through electric heating. This process also has mainly 3 steps: 1. forming a sound insulation layer; 2. paving a flat sound-absorbing cotton material on the formed sound-insulating layer; 3. and (3) punching the outline boundaries and the middle hole positions of the sound insulation layer and the sound absorption cotton by using a punching thermal compound die, and simultaneously heating and compounding the two layers of materials in the boundary areas. The key of the process is that in the step 3, a blanking knife edge is heated by adopting a resistor, a thermocouple is arranged near the knife edge for temperature monitoring, and a pressure plate is also arranged in an upper die. In the punching and edge sealing compounding process, the pressure plate firstly fixes the sound-absorbing cotton area which does not need edge sealing compounding along with the molded surface in the punching hot knife edge, then the heated punching knife edge is matched in place, and under the action of pressure and heat, the punching and the heat compounding of the sound-insulating layer, the shape boundary of the sound-absorbing cotton and the hole site boundary area are realized.
However, this method of thermal compounding also has drawbacks: the thermal composite boundary is easily pressed to be thin, the sound absorption performance loss of the sound absorption cotton is large, the sound absorption cotton cannot be in compression interference fit with peripheral parts, the sealing effect is obviously weakened, and the sound absorption and insulation performance of the sound insulation pad is seriously lost.
Disclosure of Invention
In view of this, the present application provides a composite sound insulation pad, a method for manufacturing the same, and an application thereof.
The invention provides a composite material sound insulation pad, comprising: the sound insulation layer and the composite sound absorption layer are thermally compounded on one surface of the sound insulation layer; the non-boundary area of the composite sound absorption layer is a sound absorption cotton layer, and the boundary area of the composite sound absorption layer is a polymer foaming layer for composite edge sealing.
Preferably, the composite acoustic insulator mat has a plurality of vias; the polymer foam layer for the composite edge seal comprises: a first foaming layer positioned in the boundary area of the appearance of the composite sound absorption layer and a second foaming layer positioned in the boundary area of a plurality of hole sites.
Preferably, the composite sound insulation pad is a sound insulation pad in a front wall panel of an automobile, and the sound insulation layer correspondingly covers a ventilating panel area, a front wall panel area facing an engine/motor and a pedal area;
the composite sound absorbing layer is thermally compounded on the front wall plate on the back of the sound insulating layer and is opposite to the area of the engine/motor.
Preferably, the ventilating board area and the pedal area on the back of the sound insulation layer are both compounded with sound absorption polymer foaming layers;
the sound-absorbing polymer foaming layer is made of the same material as the first foaming layer and the second foaming layer.
Preferably, the sound-absorbing polymer foam layer is integrally formed with the first foam layer and the second foam layer by foam molding.
Preferably, the material of the sound insulation layer is one or more of EVA and EPDM; the polymer foaming layer for the composite edge sealing is made of foaming PU.
The invention provides a preparation method of a composite material sound insulation pad, which comprises the following steps:
s1, providing a formed sound insulation layer;
s2, placing the sound-absorbing cotton raw material sheet on the upper surface of the sound-insulating layer formed in the step S1, taking an electric heating punching die as an upper die, and punching and thermally compounding after die assembly;
s3, placing the sound insulation layer compounded with the sound absorption cotton in the step S2 on a lower die of a foaming die, closing the die by taking an electrothermal punching die as an upper die, and prepressing and attaching the sound absorption cotton along with the molded surface of the sound insulation layer, wherein a punching hot knife of the upper die of the foaming die is biased towards the inner side of the edge sealing of the sound absorption cotton by a certain width;
and S4, injecting a polymer foaming material into the foaming mold after the mold closing in the step S3 for foaming and compounding to obtain the composite material sound insulation pad with the edge sealed by the polymer foaming layer.
Preferably, a material pressing plate is attached to an upper die of the foaming die, and when the die is closed in step S3, the material pressing plate is used for pre-pressing and attaching the sound-absorbing cotton along with the molded surface of the sound insulation layer; the offset width value in the step S3 is 5-10mm, and the interference value between the pressure plate and the sound-absorbing cotton is 5-8 mm.
Preferably, when the foam is compounded, the temperature in the cavity of the foam mold is lower than the melting point of the sound-absorbing cotton.
The invention provides application of the composite material sound insulation pad in a new energy automobile.
Compared with the prior art, in the sound insulation pad provided by the embodiment of the invention, the key area on the back surface of the thick layer is covered by the sound absorption cotton, and the polymer foaming layer is adopted for carrying out composite edge sealing. Compare in traditional sound insulation pad, this application sound insulation pad puigging's key region for inhaling the cotton cover of sound, can greatly promote sound insulation pad's sound-absorbing capacity, have better absorption to new energy automobile's high frequency sound to reduce noise reverberation time in the car. Simultaneously, this application give sound insulation and fill up with polymer foaming layer banding, guaranteed that give sound insulation and fill up the accurate and stable of thickness size of hot composite boundary department like key punchhole department to guarantee the cooperation of giving sound insulation and filling up with peripheral part, especially X to the interference value, can promote whole car front bulkhead in give sound insulation and fill up inhale the sound insulation ability, do benefit to the application.
In addition, the average thickness of the sound insulation pad is smaller than that of a sound insulation pad attached with sound-absorbing cotton on the inner side of a traditional heavy layer, and the space in the X direction can be saved by 20mm-30mm, so that the space of a passenger compartment is increased. Compare in the sound insulation pad on traditional polyurethane foaming + thick heavy layer + sound absorption cotton layer, this application can effectively reduce polyurethane foaming's use, realizes that the stick falls originally by a wide margin.
Drawings
FIG. 1 is a schematic structural view of a critical area of an acoustic insulator mat according to an embodiment of the present invention;
FIG. 2 is a schematic view of an acoustic pad inside a dash panel according to an embodiment of the present disclosure;
FIG. 3 is a cross-sectional view of a foaming die at an acoustic insulator mat component through hole in accordance with certain embodiments of the present invention;
FIG. 4 is a sound insulation test chart of the novel sound insulation mat and the conventional sound insulation mat after molding in example 1 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a composite material sound insulation pad, comprising: the sound insulation layer and the composite sound absorption layer are thermally compounded on one surface of the sound insulation layer; the non-boundary area of the composite sound absorption layer is a sound absorption cotton layer, and the boundary area of the composite sound absorption layer is a polymer foaming layer for composite edge sealing.
The composite material sound insulation pad has excellent sound absorption and insulation capacity and low cost, and is beneficial to application in the front wall plate of an automobile.
The composite material sound insulation pad provided by the embodiment of the invention is of a two-layer structure and is mainly formed by compounding a sound insulation layer and a composite sound absorption layer through a thermal compounding process. The acoustic insulator mat of the present invention includes an acoustic insulator layer, also referred to as a heavy layer.
Wherein, the sound insulation layer is made of high-density EVA sheet or hard cotton felt material; in the embodiment of the invention, the sound insulation layer may be made of EVA, or may be a thick sound insulation material of the same type as EPDM (ethylene propylene diene monomer). Some embodiments of the invention preferably employ a thick heavy layer of EVA; the soundproof layer can be conveniently formed through a hot pressing process or a vacuum adsorption forming process. In the embodiment of the present invention, the areal density of the soundproof layer may be 1.6 to 8kg/m 2 (ii) a The thickness of the soundproof layer ranges from 1mm to 5mm. In particular, the acoustic barrier may be EVA with a thickness of 2mm, i.e. EVA with an areal density of 3200 gsm.
The sound insulating mat of the present invention comprises: the thermal recombination is in the compound sound absorbing layer of puigging one side, compound sound absorbing layer non-border area is for inhaling the cotton layer of sound, compound sound absorbing layer border area is for the polymer foaming layer that is used for compound banding.
In the embodiment of the invention, the key area on one side of the thick and heavy layer of the sound insulation pad is covered by the sound absorption cotton, namely the sound absorption cotton layer; other non-critical areas are filled with polymer foam. In the embodiment of the invention, the key area of the sound insulation layer is covered by the sound absorption cotton, so that the sound absorption capability of the sound insulation pad can be greatly improved.
Wherein, the key area mainly refers to the area with higher sound absorption requirement when in use. The sound-absorbing cotton mainly refers to loose cotton type fiber materials with sound-absorbing function, and the components of the sound-absorbing cotton are organic. For example, the sound-absorbing cotton may be a porous sound-absorbing material such as PET sound-absorbing cotton, PP (polypropylene) + PET (polyethylene terephthalate) bi-component sound-absorbing cotton, or cotton wool. Fig. 1 is a schematic structural view of a key area of a soundproof pad according to an embodiment of the present invention, in fig. 1, 1 is a soundproof layer, and 2 is a sound-absorbing cotton layer in a composite soundproof layer. Inhale the shaping on cotton layer of sound and depend on the puigging, mainly will inhale cotton raw and other materials sheet of sound and carry out hot pressing complex with the puigging. In the embodiment of the present invention, the areal density of the raw material of the sound-absorbing cotton layer is generally: the density is more than or equal to 400gsm and less than or equal to 600gsm; the thickness of the sound absorption cotton layer is less than or equal to 40mm and is less than or equal to 15 mm.
For the sound insulation pad of the front wall of an automobile and the like, sound-absorbing cotton with excellent sound-absorbing performance is quite fluffy, when the edge is punched and sealed to the surface of the sound insulation layer, the edge is sealed at the position of an opening with the length of 5-10mm due to the higher temperature of a knife edge, which means that a circle of edge pressing with the size of 5-10mm is formed at the position of the opening. And, the banding problem is also true at the thermal composite appearance boundary of the sound-absorbing cotton and the sound-insulating layer. Therefore, after the sound insulation pad is installed on a real vehicle, the sound insulation pad and peripheral parts are difficult to form an interference design and great leakage is caused; if too much leakage occurs, it can cause the entire front wall acoustic insulator to fail, and can also reduce the average thickness of the acoustic insulator, which can also negatively impact acoustic performance.
According to the embodiment of the invention, the polymer foaming layer and the sound-absorbing cotton layer are subjected to edge sealing and compounding to form the composite sound-absorbing layer; namely, the boundary area of the composite sound absorption layer is a polymer foaming layer which is mainly used for composite edge sealing. At the boundary of the area covered by the sound absorption cotton on the thick and heavy layer of the sound insulation pad, the embodiment of the invention adopts polymer foaming filling, which ensures the thickness and the size of the thermal composite boundary of the sound insulation pad, such as a key through hole, to be accurate and stable, thereby ensuring the matching of the sound insulation pad and peripheral parts, particularly the interference value in the X direction (from the vehicle head to the vehicle tail), and improving the sound absorption and insulation capability of the whole sound insulation pad.
The polymer foaming layer for composite edge sealing is made of a foaming polymer foaming material, and is formed by compounding a foaming process and sound-absorbing cotton to form a composite sound-absorbing layer with uniform thickness on one surface of the thick and heavy layer. The polymer foaming layer is mainly made of foaming PU, and can also be made of other similar materials with liquid foaming molding performance. The invention preferably adopts the polyurethane foaming layer to compound the edge sealing, the polyurethane foaming and the sound-absorbing cotton can be effectively combined together, and particularly the polyurethane foaming and the sound-absorbing cotton can be mutually matched at the thermal compound boundary. Specifically, the density of the polyurethane foam layer is generally 60 to 70kg/m 3 : the width (Y-direction length) may be 5mm to 10mm.
In a specific embodiment of the present invention, the composite acoustic insulator mat has a plurality of vias; namely, the sound insulation layer and the composite sound absorption layer are correspondingly provided with a plurality of through holes. Via holes are also known as metallization holes; in the double-sided board and the multilayer board-shaped parts, in order to communicate the printed wires among the layers, a common hole, namely a through hole, is drilled at the intersection of the wires which need to be communicated among the layers. For example, there are tens of holes on the automobile front wall sound-proof pad, including some key through holes. The metal plate is provided with holes, and the sound insulation pad is also provided with holes. Enclose before the car on the panel beating, have a lot of trompils, including the via hole of footboard mounting hole, main line pencil, air conditioner fresh air inlet, air conditioner expansion valve trompil, steering column trompil, corresponding, enclose before and give sound insulation and fill up also need cooperate the trompil to dodge relevant part. The opening hole causes deterioration of airtightness of the automobile, and therefore, the part passing through the opening hole must be fitted with the soundproof pad to secure the airtightness.
For the sound insulation pad with the through holes, the boundary area of the composite sound absorption layer comprises an exterior boundary area and a hole site boundary area; the polymer foam layer for the composite edge seal comprises: the first foaming layer is positioned in the exterior boundary area of the composite sound absorbing layer, and the second foaming layer is positioned in the boundary area of the plurality of hole sites. Generally, the first foamed layer and the second foamed layer are made of the same material, for example, both are polyurethane foamed layers, and can be integrally foamed and molded.
The embodiment of the invention particularly provides an inner sound insulation pad of an automobile front wall panel, namely the composite material sound insulation pad is applied as the inner sound insulation pad of the automobile front wall panel. The sound insulation pad in the automobile front wall plate is a part with a complex three-dimensional curved surface, and can be called as the front wall plate inner sound insulation pad, the front wall sound insulation pad and the like for short; typically, the circumference of the outer profile of the part is about 5m, and there are tens of holes in the part.
The embodiment of the invention provides an inner sound insulation pad of an automobile front wall plate, which comprises: the sound insulation layer and the composite sound absorption layer are thermally compounded on the back surface of the sound insulation layer; the sound insulation layer correspondingly covers the ventilating plate area, the front wall plate area facing the engine/motor and the pedal area;
the composite sound absorption layer is thermally compounded on the front wall plate of the sound insulation layer just opposite to the engine/motor area, the non-boundary area of the composite sound absorption layer is a sound absorption cotton layer, and the boundary area of the composite sound absorption layer is a polymer foaming layer for composite edge sealing.
Referring to fig. 2, fig. 2 is a schematic view of an acoustic pad in a dash panel according to an embodiment of the present invention. Wherein the soundproof layer includes: a cowl area, a dash area facing the engine/motor area (i.e., a center tunnel area), a pedal area consisting of a pedal area-left and a pedal area-right. The materials, the forming and the like of the sound insulation layer are as described above, and are not described in detail herein.
On the back of the sound insulation layer, the middle front wall plate is mainly made of sound absorption cotton serving as a sound absorption material in the area facing the engine/motor, and the sound absorption cotton is formed by foaming polyurethane and other polymers and compounding thick layers at all key through holes.
The key area (about the middle third) of the front wall sound insulation pad provided by the embodiment of the invention is covered by the sound absorption cotton layer, and the sound absorption capability of the sound insulation pad can be greatly improved corresponding to the sound absorption cotton layer, so that high-frequency sound of a new energy automobile can be better absorbed, and the noise reverberation time in the automobile can be reduced. The invention can solve the problem that the large-area edge pressing part formed after the sound-absorbing cotton is formed is not enough in thickness by sealing the edge through the polymer foaming process corresponding to the polymer foaming layer for composite sealing, and can ensure the accurate and stable thickness dimension of the key through hole of the sound-insulating pad, thereby ensuring the matching of the sound-insulating pad and peripheral parts, particularly the interference value in the X direction, improving the sound absorption and insulation capability of the sound-insulating pad in the whole front dash panel, and also solving the sound insulation problem of high-frequency noise of a motor of a new energy vehicle.
The sound-absorbing cotton layer and the polymer foaming layer for composite edge sealing are made of the same materials, the same thicknesses and the like; wherein the polymer foam layer comprises: a first foaming layer positioned in the boundary area of the appearance of the composite sound absorption layer and a second foaming layer positioned in the boundary area of a plurality of hole sites.
In a preferred embodiment of the present invention, the sound absorbing polymer foam layer is combined with both the ventilating board area and the foothold area on the back of the sound insulation layer. The sound-absorbing polymer foam layer is a low-density polymer foam layer which mainly has a large area relative to the boundary and has the sound-absorbing effect. Specifically, the sound-absorbing polymer foaming layer is made of the same material as the first foaming layer and the second foaming layer; the sound-absorbing polymer foaming layer, the first foaming layer and the second foaming layer are integrally foamed and molded.
Wherein the lower portion of the sound insulating mat in the dash panel extends to a region where a driver and a passenger can step on the sound insulating mat when the driver and the passenger are seated, and the region is a high-perception region where the feet of the driver and the passenger step on the sound insulating mat. Although the sound-absorbing cotton has the advantage of excellent sound-absorbing performance, the sound-absorbing cotton is quite fluffy and soft, and the supporting strength of the sound-absorbing cotton is lower than that of a PU (polyurethane) foam material. In this area, if the sound-absorbing cotton is used as the sound-absorbing material on the back of the sound-insulating pad, the bad feeling that the feet of the driver and passengers are soft when stepping on the pad is easily caused. In some embodiments of the invention, the sound absorption and insulation performance of the sound insulation pad is ensured and the support performance of the pedal area is improved by filling foaming materials such as PU and the like in the pedal area, so that the problem that the pedal area is soft due to the sound insulation pad formed by all sound absorption cotton is solved.
In the embodiment of the invention, low-density polymer foams such as PU and the like are adopted as sound-absorbing materials in the pedal area, the left channel area, the middle channel area, the right back surface and the ventilating plate area, the middle front wall plate is opposite to the engine/motor area, sound-absorbing cotton is adopted as the sound-absorbing material, and the outer boundary and the via hole boundary of the whole sound-insulating pad and the boundary of the sound-absorbing cotton adjacent to the foaming layer covering area are subjected to composite edge sealing by adopting foaming polymers.
The non-critical area and the through hole of the sound insulation pad of the embodiment of the invention are filled with polyurethane foam, and the polyurethane foam and the sound absorption cotton can be effectively combined together, especially the polyurethane foam and the sound absorption cotton are matched at the junction and the through hole. Compared with the traditional sound insulation pad with polyurethane foaming, a thick and heavy layer and a sound absorption cotton layer, the sound insulation pad can effectively reduce the use of polyurethane foaming, and realize that the cost of a single piece is greatly reduced. The sound insulation pad is of a two-layer structure; the average thickness of the sound insulation pad is smaller than that of the sound insulation pad with sound absorption cotton attached to the inner side of the traditional thick and heavy layer, and the space in the X direction is saved by 20-30 mm, so that the space of a passenger compartment is enlarged.
The embodiment of the invention provides a preparation method of the composite material sound insulation pad, which comprises the following steps:
s1, providing a formed sound insulation layer;
s2, placing the sound-absorbing cotton raw material sheet on the upper surface of the sound-insulating layer formed in the step S1, using an electrothermal punching die as an upper die, closing the die, punching and thermally compounding;
s3, placing the sound insulation layer compounded with the sound absorption cotton in the step S2 on a lower die of a foaming die, closing the die by taking an electric heating punching die as an upper die, and prepressing and attaching the sound absorption cotton along with the molded surface of the sound insulation layer, wherein a punching hot knife of the upper die of the foaming die is biased towards the inner side of the edge sealing of the sound absorption cotton by a certain width;
and S4, injecting a polymer foaming material into the foaming mold after the mold is closed for foaming and compounding to obtain the composite material sound insulation pad with the edge sealed by the polymer foaming layer.
The embodiment of the invention provides a formed sound insulation layer; the sound insulation layer may be formed by a conventional hot pressing process or a vacuum adsorption process. Taking the EVA sound insulation layer as an example, the material EVA of the sound insulation layer can be heated and then sent to an EVA plastic suction forming die, and the designed molded surface can be formed by EVA through pressure maintaining and cooling setting.
The embodiment of the invention adopts the technical scheme that the sound insulation layer is firstly compounded with the sound absorption cotton: specifically, the sound-absorbing cotton raw material sheet can be placed on the upper surface of the EVA sound-insulating layer formed by plastic suction, the upper die is an electrothermal punching die, the outer boundary of the part and the inner hole site of the part are punched by die assembly, and the sound-absorbing cotton-compounded sound-insulating layer is obtained by thermal compounding. When the sound insulation layer and the sound absorption cotton are thermally compounded, a knife edge needs to be arranged on an upper die of the absorption die, and the key through hole punching is completed through the technology of punching the upper die of the absorption die. Wherein the temperature of the thermal compounding of the sound insulation layer and the sound absorption cotton is generally controlled at 120 ℃.
According to the embodiment of the invention, after the EVA sound insulation layer and the sound absorption cotton are thermally compounded, the cooled EVA compounded with the sound absorption cotton is placed on the lower die of the foaming die, is attached to the molded surface of the die and is well positioned; the electrothermal punching die is used as an upper die, and then an upper die (support) moves towards a lower die to close the die. In the mould closing process, the sound-absorbing cotton is pre-pressed and attached along with the molded surface of the sound-insulating layer, and meanwhile, the punching hot knife of the upper mould of the foaming mould is biased to the inner side of the edge sealing of the sound-absorbing cotton by a certain width to complete mould closing.
The embodiment of the invention researches a polyurethane foaming and sound absorption cotton edge sealing compound mode and a related die after EVA and sound absorption cotton are molded. After the lower die formed by adsorption and the upper die compounded by hot punching and edge sealing are combined to form one set of die, the lower die is pressed on the fluffy sound-absorbing cotton in the form of a hot punching and cutting upper die pressing plate on the other set of foaming die. The upper die of the foaming die is additionally provided with a material pressing plate (also called a material sealing plate), and when the foaming die is closed, the part of the material pressing plate suspended on the upper die frame firstly contacts the sound-absorbing cotton, so that the material pressing plate performs prepressing and laminating on the sound-absorbing cotton along with the molded surface of the sound insulation layer.
And the interface of the pressure plate and the punching hot knife is not superposed with the outer contour of the part and the edge surface of the inner hole site, but is biased to the inner side of the heat-sealing edge of the sound-absorbing cotton by a certain width. For avoiding pressing the cotton quilt compression of inhaling of the cotton volume of sound that the flitch wall thickness is too thick to lead to bigger area, avoid pressing the flitch overlength simultaneously to lead to inhaling the cotton volume of sound bigger than, more avoid pressing the flitch overlength to lead to inhaling when the cotton compression of sound is not enough, polyurethane foaming raw and other materials spill over to inhale the cotton surface of sound and lead to the product shaping failure, the design of pressing the flitch is also crucial.
Preferably, the offset width value of the pressure plate of the upper die of the foaming die to the inner side of the heat-sealing edge of the sound-absorbing cotton is 5-10 mm. At the through hole, in the prior art, the fragile sound absorption cotton is subjected to edge sealing by the pressure plate, so that the thickness of the sound absorption cotton at the through hole is as thin as 15mm from the thickness in a design state, the sound absorption cotton is actually thinned as thin as 2mm, and sound leakage of the through hole is very easy to occur at the moment. The embodiment of the invention ingeniously avoids the through hole, carries out edge pressing at the position far away from the through hole, and then carries out PU foaming at the through hole through edge sealing by a foaming process and supplement of other areas so as to meet the requirement of accurate thickness design. After deflection, the interference value of the pressure plate and the sound-absorbing cotton is required to be within the range of 5 mm-8 mm, and corresponding adjustment can be made according to the thickness of the sound-absorbing cotton; the interference value varies according to the thickness of the sound-absorbing cotton, and is generally less than half of the thickness. In addition, the pressure plate of the upper die of the foaming die is directly connected with the upper die and does not have a structure which can move relative to the upper die.
And finally, the material sealing plate isolates sound-absorbing cotton, polymer foaming materials are injected into the foaming mould after the mould is closed, foaming and compounding are carried out, so that the formed polymer foaming layer is compounded with the sound-absorbing cotton edge sealing, and the polymer foaming layer can be filled in other non-critical areas in a foaming manner, and the novel sound-insulating pad formed by foaming and compounding the sound-absorbing cotton and the polymer is obtained.
In the embodiment of the present invention, the polymer foam is preferably a polyurethane foam, and may be other liquid similar polymer foam. Fig. 3 is a cross-sectional view of the foaming mold at the through hole of the sound insulation pad part according to the embodiment of the present invention, in fig. 3, 1 is a heavy layer, 2 is a sound-absorbing cotton layer after hot press molding, 3 is an upper mold material sealing plate, and 4 is a polymer foaming layer.
The width of the traditional pressure plate is larger than 10mm, and the traditional pressure plate is designed to be attached to EVA in a zero mode so as to avoid flash. Through a plurality of experimental researches, the width of the material pressing plate 3 in the figure 3 can be smaller than 5mm, and meanwhile, the design state only interferes with the sound absorption cotton by 5-8mm, so that the sound absorption cotton is not completely compressed, and the thickness of the boundary of PU and the sound absorption cotton can be further optimized. In the embodiment of the invention, the thermal composite boundary of the sound-absorbing cotton and the EVA is covered again by PU foaming to optimize the performance of the sound-insulating pad part.
The embodiment of the invention can adjust the pressure maintaining time and temperature of foaming compounding to finish the final product. In the embodiment of the invention, when the foaming is compounded, the temperature in the foaming mold cavity is lower than the melting point of the sound absorption cotton. For example, the melting point of the sound-absorbing cotton is 100-120 ℃, and the temperature of the foaming mold cavity can be controlled to be 65-75 ℃. The mould temperature is lower when foaming, does not have very big influence to the cotton thickness of inhaling the sound, and cotton thickness is inhaled in guarantee that can furthest to promote the sound-absorbing capacity of part.
The composite material sound insulation pad manufactured in the embodiment of the invention can be a sound insulation pad in a front wall board shown in fig. 1, wherein PU foam is adopted as sound absorption materials in a pedal area, a left channel area, a middle channel area, a pedal area, a right back surface and a ventilation board area, sound absorption cotton is adopted as the sound absorption materials in the middle front wall board, the area right facing an engine/motor, and the outer boundary, the via hole boundary and the boundary adjacent to the PU coverage area of the sound absorption cotton are subjected to composite edge sealing by PU. The sound insulation pad is tested in a reverberation room and a sound insulation room, the sound insulation performance of the sound insulation pad in a full frequency band is far better than that of the traditional scheme, and the sound insulation pad can be completely popularized and implemented on new energy vehicle types. Therefore, the invention also provides the application of the composite material sound insulation pad in the new energy automobile.
For further understanding of the present application, the composite acoustic insulator mat provided herein, its method of manufacture and use are specifically described below in conjunction with the examples.
Example 1
Firstly, heating the EVA of the sound insulation layer material, then conveying the heated material to an EVA plastic suction forming die, and keeping pressure, cooling and shaping to form a designed molded surface (such as the molded surface of the sound insulation pad in the front wall plate shown in figure 1) by EVA molding, so as to obtain the EVA sound insulation layer with the thickness of 2mm, namely the EVA with the surface density of 3200 gsm.
And secondly, placing the sound-absorbing cotton raw material sheet (comprising PP and PET, the surface density of 400gsm and the thickness of 25 mm) on the upper surface of the EVA which is formed by plastic suction, wherein the middle third of the sound-absorbing cotton raw material sheet is provided with an electrothermal punching die, closing the die to punch out the outer boundary and the inner hole site of the part, and thermally compounding to obtain the sound-absorbing cotton compounded sound insulation layer. When the sound insulation layer and the sound absorption cotton are thermally compounded, a knife edge is added on the upper die of the adsorption die, and the key through hole punching is completed through the process of punching the upper die of the adsorption die. Critical vias are for example: air conditioner fresh air inlet (200mm 100mm), air conditioner expansion valve (90 x 140mm), main pencil through-hole (120 x 100mm).
Thirdly, placing the formed EVA and the sound absorption cotton, namely the cooled EVA sound insulation layer compounded with the sound absorption cotton, into a lower mold of a foaming forming mold according to the molded surface, and attaching and positioning the EVA sound insulation layer and the sound absorption cotton to the molded surface of the mold; then, the upper die frame moves towards the lower die, the part of the sealing plate suspended on the upper die frame is firstly contacted with the sound-absorbing cotton, and the sealing plate is used for prepressing and attaching the sound-absorbing cotton along with the formed EVA molded surface. And the interface of the pressure plate and the punching hot knife, the outer contour of the part and the edge surface of the inner hole site are not superposed, the pressure plate and the punching hot knife are offset towards the inner side of the heat sealing edge of the sound-absorbing cotton by the width of 5mm, and the interference value of the pressure plate and the sound-absorbing cotton is 5-8mm, so that the die closing is completed.
And fourthly, after the upper die of the PU foaming die is closed, the sealing plate isolates the sound-absorbing cotton, and PU material is injected from the pouring gate for foaming and compounding. And the temperature of the foaming mold cavity is controlled to be 65-75 ℃, the pressure maintaining time is 120s, so that the formed PU foaming layer is compounded with the sound absorbing cotton in edge sealing mode, and foams are filled in a left foot area, a middle channel area, a right foot area, a back surface and a ventilating plate area, and the outer boundary of the whole sound insulating pad, the boundary of the through hole and the boundary adjacent to the sound absorbing cotton and the PU covering area are all edge-sealed PU foaming layers. The density of the PU foamed layer in each region was 65kg/m 3 (ii) a The PU foaming layer in the edge sealing area is slightly pressed with sound absorbing cotton and is effectively compounded together.
And fifthly, finishing the foaming process to obtain the novel sound insulation pad formed by foaming and compounding the sound absorption cotton and the PU. Opening the mold and taking out the sound insulation pad part.
Carry out the contrast test with the sound insulation performance of novel sound insulation pad after the shaping and the sound insulation pad EVA + PU scheme of tradition, the material scheme of tradition EVA + PU is: EVA with the thickness of 2mm, namely EVA with the surface density of 3200gsm, and the density of a PU foaming layer is 65Kg/m 3 The thickness is as above. Traditional PU foaming layer corresponds and covers whole puigging, through the foaming shaping of mould closing, goes up the die-cut completion of EVA + PU after the mould area will be moulded simultaneously to the edge of a knife.
The novel sound insulation pad and the traditional scheme are both used for a new energy certain vehicle type (an electric vehicle with more high-frequency noise or an electric plug-in hybrid vehicle), and a sound insulation curve pair obtained by testing in a reverberation room-sound insulation room is shown in fig. 4. As can be seen from FIG. 4, the sound insulation performance of the novel sound insulation pad of the invention is far superior to that of the traditional scheme, even 10-20dB improvement. In the new energy vehicle model, the high-frequency noise of the motor accounts for a large proportion, so that the novel sound insulation pad has strong absorption capacity on the high-frequency noise and is beneficial to being widely applied to the new energy vehicle model.
Furthermore, the weight of the entire acoustic insulator mat of the present invention is reduced by 500g compared to "conventional polyurethane foam + thick heavy layer" while being consistent with the conventional scheme in average thickness.
Compared with a sound insulation pad with a three-layer structure of traditional polyurethane foaming, a thick heavy layer and a sound absorption cotton layer, the sound insulation pad is at least 10mm thin. Whereas in automotive design a space of 10mm is of utmost importance for the complete vehicle. Therefore, the composite material sound insulation pad provided by the invention can improve the acoustic performance of the whole vehicle, reduce the requirement on thickness and ensure the support of a pedal area, namely the comfort of passengers.
Example 2
For new energy vehicle types with higher requirements on overall vehicle performance, the surface density of the sound-absorbing cotton adopted in the embodiment is 600g/m 2 40mm in thickness, 5Kg/m in EVA area density 2 (ii) a The molding process and the like were the same as in example 1, and a novel soundproof pad was prepared.
The cost of this material scheme is high, and it needs to be used on higher-grade vehicle models. This embodiment uses this novel sound insulating pad part, and wherein, the high areal density of EVA has increased the sound insulating properties of low frequency noise, and the high areal density inhales the sound cotton and has increased the absorption of high frequency noise.
The above description is only a preferred embodiment of the present invention, and it should be noted that various modifications to these embodiments can be implemented by those skilled in the art without departing from the technical principle of the present invention, and these modifications should be construed as the scope of the present invention.

Claims (5)

1. A composite acoustic insulator mat comprising: the sound insulation layer and the composite sound absorption layer are thermally compounded on one surface of the sound insulation layer; the non-boundary area of the composite sound absorption layer is a sound absorption cotton layer, and the boundary area of the composite sound absorption layer is a polymer foaming layer for composite edge sealing;
the composite sound insulating pad is provided with a plurality of through holes; the polymeric foam layer for a composite edge seal comprises: the first foaming layer is positioned in the exterior boundary area of the composite sound absorbing layer, and the second foaming layer is positioned in the boundary areas of the plurality of hole sites;
the composite material sound insulation pad is a sound insulation pad in a front wall panel of an automobile, and the sound insulation layer correspondingly covers a ventilating panel area, an area of the front wall panel opposite to an engine/motor area and a pedal area;
the composite sound absorbing layer is thermally compounded on the front wall plate on the back of the sound insulating layer and is opposite to the engine/motor area;
the ventilating board area and the pedal area on the back of the sound insulation layer are both compounded with sound absorption polymer foaming layers;
the sound-absorbing polymer foaming layer is made of the same material as the first foaming layer and the second foaming layer;
the sound-absorbing polymer foaming layer, the first foaming layer and the second foaming layer are integrally foamed and molded;
the sound insulation layer is made of one or more of EVA (ethylene vinyl acetate) or EPDM (ethylene-propylene-diene monomer); the polymer foaming layer for composite edge sealing is made of foaming PU with the density of 60-70 kg/m 3 。
2. A method of making the composite acoustic insulator mat of claim 1 comprising the steps of:
s1, providing a formed sound insulation layer;
s2, placing the sound-absorbing cotton raw material sheet on the upper surface of the sound-insulating layer formed in the step S1, taking an electric heating punching die as an upper die, and punching and thermally compounding after die assembly;
s3, placing the sound insulation layer compounded with the sound absorption cotton in the step S2 on a lower die of a foaming die, closing the die by taking an electrothermal punching die as an upper die, and prepressing and attaching the sound absorption cotton along with the molded surface of the sound insulation layer, wherein a punching hot knife of the upper die of the foaming die is biased towards the inner side of the edge sealing of the sound absorption cotton by a certain width;
and S4, injecting a polymer foaming material into the foaming mold after the mold closing in the step S3 for foaming and compounding to obtain the composite material sound insulation pad with the edge sealed by the polymer foaming layer.
3. The preparation method according to claim 2, wherein a material pressing plate is attached to an upper die of the foaming die, and when the die is closed in step S3, the material pressing plate is used for pre-pressing and attaching the sound-absorbing cotton along with the molded surface of the sound insulation layer; the offset width value in the step S3 is 5-10mm, and the interference value between the pressure plate and the sound-absorbing cotton is 5-8 mm.
4. The preparation method of claim 2, wherein the temperature in the foaming mold cavity is lower than the melting point of the sound-absorbing cotton during foaming and compounding.
5. Use of the composite acoustic insulator mat of claim 1 in new energy vehicles.
CN201910424854.5A 2019-05-21 2019-05-21 Composite material sound insulation pad, and preparation method and application thereof Active CN111976247B (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107428899A (en) * 2015-03-20 2017-12-01 井上株式会社 Polyurethane foam
CN107443715A (en) * 2016-05-31 2017-12-08 上海汽车集团股份有限公司 Manufacture the mould and method of vehicle noise insulation pad

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107428899A (en) * 2015-03-20 2017-12-01 井上株式会社 Polyurethane foam
CN107443715A (en) * 2016-05-31 2017-12-08 上海汽车集团股份有限公司 Manufacture the mould and method of vehicle noise insulation pad

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