Acoustic composite for automotive applications

Abstract

The present invention relates to an acoustic composite of nonwoven material injected with polymeric film material for automotive applications and a corresponding method of forming that provides a relatively broad range of airflow resistance and acoustic performance. This airflow resistance and / or acoustic performance can be conveniently adjusted by material selection and production methods.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 337,767, filed May 3, 2022, the teachings of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to nonwoven acoustic composites infused with polymeric film materials for automotive applications and corresponding methods of formation, which provide a relatively wide range of airflow resistance and acoustic performance. Such airflow resistance and / or acoustic performance can be conveniently adjusted through material selection and production methods. Background Art

[0004] Adjusting and optimizing airflow resistance and acoustic performance within an automobile interior remains an evolving field. More specifically, there remains a continuing need to suppress the transmission of noise generated from the exterior of the vehicle into the interior of the vehicle. To achieve this goal, various efforts have been made to develop multi-layer laminates derived from nonwoven-type materials to address these issues. Summary of the invention

[0005] A method for forming an acoustic composite, the method comprising: providing a layered precursor structure having: an upper nonwoven layer having a thickness of 1.0 mil to 200.0 mils and a basis weight of 10 g / m 2 Up to 200g / m 2 ; Polymer film layer having a thickness of 0.1 mil to 40.0 mils and a basis weight of 10 g / m 2 Up to 90g / m 2 The lower nonwoven absorbent layer has a thickness of 75.0 mils to 4000.0 mils and a basis weight of 100 g / m 2 Up to 3000g / m 2 The layered precursor structure may then be heated and pressurized and formed into the acoustic composite, wherein the acoustic composite exhibits an airflow resistance in Rayls (MKS) in the range of 800 to 10,000.

[0006] A layered precursor structure suitable for forming an acoustic composite for an automobile, the layered precursor structure comprising: an upper nonwoven layer having a thickness of 1.0 mil to 200.0 mils and a basis weight of 10 g / m 2 Up to 200g / m 2 ; A polymer film layer having a thickness of 0.1 mil to 10.0 mils and a basis weight of 10 g / m 2 Up to 90g / m 2and a lower nonwoven fiber absorbent layer having a thickness of 75.0 mils to 4000.0 mils and a basis weight of 100 g / m 2 Up to 3000g / m 2 .

[0007] A method for forming an acoustic composite, the method comprising: providing a layered precursor structure having: an upper nonwoven layer having a thickness in the range of 55.0 mils to 800.0 mils and a basis weight of 400 g / m 2 Up to 2000g / m 2 ; A polymer film layer having a thickness of 0.1 mil to 40.0 mils and a basis weight of 10 g / m 2 Up to 90g / m 2 ; a middle nonwoven layer having a thickness of 1.0 mils to 200.0 mils and a basis weight of 10 g / m 2 Up to 200g / m 2 and a lower nonwoven fiber absorbent layer having a thickness of 75.0 mils to 4000.0 mils and a basis weight of 100 g / m 2 Up to 3000g / m 2 ; and heating and pressurizing the layered precursor structure and forming the acoustic composite, wherein the acoustic composite exhibits an airflow resistance in Rayls (MKS) in the range of 800 to 10,000.

[0008] A method for forming an acoustic composite, the method comprising: providing a three-layer precursor having a thickness in the range of 55.0 mils to 800.0 mils and a basis weight of 400 g / m 2 Up to 2000g / m 2 The upper nonwoven layer has a thickness of 0.1 mil to 40.0 mils and a basis weight of 10 g / m 2 Up to 90g / m 2 The polymer film layer has a thickness of 1.0 mil to 200.0 mils and a basis weight of 10 g / m 2 Up to 200g / m 2 The intermediate nonwoven layer is provided; and the three-layer structure is heated and pressed to form a three-layer composite. Then, a thickness of 75.0 mils to 4000.0 mils and a basis weight of 100 g / m 2 Up to 3000g / m 2 A lower nonwoven fibrous absorbent layer is formed by attaching the lower nonwoven fibrous absorbent layer to the middle layer of the three-layer composite, thereby forming the acoustic composite, wherein the acoustic composite exhibits an airflow resistance in Rayls (MKS) in the range of 800 to 10,000.

[0009] A layered precursor structure suitable for forming an acoustic composite for an automobile, the layered precursor structure comprising: an upper nonwoven layer having a thickness in the range of 55.0 mils to 800.0 mils and a basis weight of 400 g / m 2 Up to 2000g / m 2 ; A polymer film layer having a thickness of 0.1 mil to 40.0 mils and a basis weight of 10 g / m 2 Up to 90g / m 2 and an intermediate nonwoven layer having a thickness of 1.0 mil to 200.0 mils and a basis weight of 10 g / m 2 Up to 200g / m 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A first example of a precursor layered structure of a nonwoven / polymer film assembly that is subsequently heated and pressed into a composite for automotive applications herein is shown.

[0011] Figure 2 A second example of a precursor nonwoven material / polymer film assembly that is subsequently heated and pressed into a composite for automotive applications herein is shown. DETAILED DESCRIPTION

[0012] The present invention is directed to a nonwoven acoustic composite selectively infused with a molten polymeric film material. Thus, the acoustic composite referred to in the present invention may be understood as a nonwoven material in which all or part of the nonwoven material is infused with a molten polymeric film material. The polymeric film material is preferably infused into the nonwoven material only by applying heat and pressure, as described herein.

[0013] The infused nonwoven material thus formed can now provide selected airflow resistance and acoustic properties. More specifically, the infused nonwoven material has the nonwoven fibers coated with a polymer film, so that the composite produced retains openings and porosity within and outside the nonwoven fibers, making it suitable for providing a composite for automotive acoustic applications with desired airflow resistance and acoustic properties.

[0014] Figure 1A first example of a precursor layered structure of a nonwoven material / polymer film assembly 10 is shown, which is then heated and pressed into a composite for automotive applications herein. As shown, preferably starting with an upper nonwoven layer 12, a polymer film layer 14, and a lower nonwoven absorbent layer 16. The thickness of the upper nonwoven layer 12 is preferably 1.0 mil to 200.0 mils, including all values ​​and increments therein. For example, 1.0 mil to 100.0 mils, or 1.0 mil to 50.0 mils or 1.0 mil to 25.0 mils or 1.0 mil to 15.0 mils. 1 mil here refers to 0.001 inch. The basis weight of the upper nonwoven layer is also preferably 10 g / m 2 Up to 200g / m 2 The range includes all individual values ​​and increments therein. For example, a particularly preferred range is 10 g / m 2 Up to 60g / m 2 or 10g / m 2 Up to 25g / m 2 .

[0015] The upper nonwoven layer 12 may preferably be selected from polymeric materials in fiber form, such as aromatic polyesters (e.g., poly(ethylene terephthalate) or PET), polyamides, cotton, cellulose, polyacrylic acid, polyacrylonitrile, aromatic polyamides, and / or olefin fibers. Such nonwoven fibers may also be produced using recycled or regenerated polymers. In addition, the fibers in the nonwoven layer 12 may preferably include monocomponent fibers or bicomponent fibers. The nonwoven material in the layer 12 may also preferably be needle-punched fibers, air laid fibers, spunbond fibers, spunlace fibers, wet laid fibers, and / or carded fibers.

[0016] The thickness of the polymer film layer 14 is preferably 0.1 mil to 40.0 mil, including all values ​​and increments therein. For example, 0.1 mil to 20.0 mils, or 0.1 mil to 10.0 mils, or 0.1 mil to 5.0 mils, or 0.1 mil to 2.0 mils. In addition, the basis weight of the polymer film material is preferably 10 g / m 2 Up to 90g / m 2 range, including all values ​​and increments therein, such as 10g / m 2 Up to 50g / m 2 , or 10g / m 2 Up to 25g / m 2. The polymer film layer is preferably selected from thermoplastic polymer materials, which refer to polymer resins that can be repeatedly heated and made to flow. Such thermoplastic polymer materials preferably include polyethylene, polypropylene, polyester, polyamide, poly(vinyl chloride), cellulose acetate, polyethylene-vinyl acetate copolymers, acrylic polymers and polyurethanes. More preferably, in terms of polyethylene, the polymer film is preferably selected from low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and even polyethylene films prepared with metallocene catalysts (m-PE). Copolymers of ethylene and acrylic acid (EAA resins) may also be included. According to ISO1133 (2011) standard, the melt flow index (MFI) of the polymer film thus selected is preferably between 0.5 g / 10 min and 5.0 g / 10 min, including all values ​​and increments therein.

[0017] The polymer film can also be a film with perforations or a closed film without perforations. In addition, the film layer can also be a multilayer polymer film material, for example a three-layer polymer film, wherein the melting points of the upper polymer film and the lower polymer film are relatively lower than the melting point of the polymer film of the central layer.

[0018] The nonwoven absorbent layer 16 preferably has a thickness in the range of 75.0 mils to 4000.0 mils (including all individual values ​​and increments therein) and a basis weight of 100 g / m 2 Up to 3000g / m 2 The polymer material of the fibrous absorbent layer 16 is preferably selected from aromatic polyesters (such as poly(ethylene terephthalate) or PET), polyamides, cotton, cellulose, polyacrylic acid, polyacrylonitrile, aromatic polyamides and / or olefin fibers. In addition, the fibers in the nonwoven fibrous absorbent layer 16 may include monocomponent fibers or bicomponent fibers. The nonwoven material in the layer 16 may also be needle-punched fibers, air-laid fibers, spunbond fibers, spunlace fibers, wet-laid fibers and / or carded fibers.

[0019] In addition, it is worth noting that the melting point of the polymer used for both the nonwoven layer 12 and the nonwoven layer 16 is preferably higher than the melting point of the film layer 14. For example, the polymer used to form both the nonwoven layer 12 and the nonwoven layer 16 can be a non-melting polymer (e.g., aromatic polyamide) and / or in the range of 80°C to 300°C. A particularly preferred melting range is 180°C to 265°C. In a particularly preferred embodiment, the melting point of the polymer used for the nonwoven layers 12, 16 is at least 10°C to 20°C higher than the melting point of the polymer film layer 14.

[0020] The nonwoven material / polymer film precursor assembly 10 is then heated and pressurized, wherein the polymer film layer melts and flows into the upper nonwoven layer 12 and the lower nonwoven fibrous absorbent layer 16, which are preferably not melted. The pressure used is preferably in the range of 0.5 psi to 150 psi, including all values ​​and increments therein. For example, the pressure can be in the range of 0.5 psi to 100 psi, or 0.5 psi to 100.0 psi, or 0.5 psi to 90.0 psi, or 0.5 psi to 80 psi. With, for example, the nonwoven layer 12 ( Figure 1 ) etc. can preferably be in the range of 275°F to 400°F. The tool can include, for example, a roll having the above surface temperature and capable of providing the above pressure required for the nonwoven material / polymer film assembly.

[0021] During this process, the polymer resin in the film layer 14 is melted and infused into all or part of the nonwoven fibers in the upper nonwoven layer 12 and / or the nonwoven fiber absorbent layer 16. The resulting product can provide the ability to provide selected and adjustable airflow resistance and acoustic performance in the final product. This performance can be characterized in Rayls (MKS), and this performance is preferably in the range of 800 Rayls to 10,000 Rayls (MKS), including all values ​​and increments therein. More preferably, the Rayl value is in the range of 3000 Rayls to 9000 Rayls (MKS).

[0022] Thus, an acoustic layer can now be provided for automotive applications which can be tailored to provide selected targeted acoustic properties by selecting nonwoven and polymer film materials and then applying heat and pressure in a mold to achieve such targeted performance. The lower surface 18 of the nonwoven / polymer film assembly 10 can then be adhered to the interior surface of the vehicle sheet metal.

[0023] Figure 2 A second example of a nonwoven material / polymer film precursor assembly is shown, which is subsequently heated and pressed into a composite for an automotive application. In this example, a nonwoven upper fiber layer 20 that can be described as relatively dense is used. This fiber layer 20 is characterized by a thickness preferably between 55.0 mils and 800.0 mils, including all individual values ​​and ranges therein. For example, the thickness of the fiber layer 20 can range from 115.0 mils to 400.0 mils. In addition, the basis weight of the fiber layer 20 is preferably 400 g / m 2 Up to 2000g / m 2 For example, the basis weight of the fiber layer 20 may be 800 g / m 2 Up to 1500g / m 2 within the range.

[0024] Figure 2 The polymer film layer 14 in the Figure 1 Similarly, Figure 2 The nonwoven layer 12 in the Figure 1 As described above, but now in what can be described as an intermediate nonwoven layer, because the nonwoven layer is located below the polymer film layer 14. In addition, Figure 2 The lower nonwoven fiber absorbent layer 16 in the Figure 1 described.

[0025] Therefore, with Figure 1 The situation is similar to that in Figure 2 , the melting point of the polymer used for the relatively dense upper nonwoven fiber layer 20 and the nonwoven layer 12 is higher than the melting point of the polymer film layer 14. Similarly, the melting point of the lower nonwoven fiber layer 16 is preferably higher than the melting point of the polymer film layer 14. Therefore, the polymer used for the nonwoven layer 20, the nonwoven layer 12 and the lower nonwoven fiber layer 16 can be a non-melting polymer (such as aromatic polyamide) and / or range between 80°C and 300°C. A particularly preferred melting range is 180°C to 265°C. In a particularly preferred embodiment, Figure 2 The melting points of the polymers used in the nonwoven layers 20 , 12 , 16 shown in FIG. 1 are all at least 10° C. to 20° C. higher than the melting point of the polymer film layer 14 .

[0026] It should now be noted that for any nonwoven layer described herein, e.g. Figure 1 and / or Figure 2 The thickness of the nonwoven layers 12, 16 and / or 20 shown in FIG. 1 is preferably measured according to DIN EN ISO 9073-2 entitled "Textiles - Test methods for nonwovens - Part 2: Determination of thickness".

[0027] Then in the mold Figure 2 The above nonwoven material / polymer film precursor assembly in is heated and pressurized, wherein the polymer film layer 14 has melted and now flows into the upper dense nonwoven fiber layer 20 and the lower nonwoven fiber layer 12, which are preferably not melted. The pressure used is also preferably in the range of 0.5psi to 150psi, including all values ​​and increments therein. For example, once again, the pressure can be in the range of 0.5psi to 100psi, or 0.5psi to 100.0psi, or 0.5psi to 90.0psi, or 0.5psi to 80psi. With, for example, the nonwoven layer 20 ( Figure 2) The surface temperature of the tool in contact may preferably be in the range of 275°F to 450°F, more preferably in the range of 370°F to 400°F. The tool may also include, for example, a roll having the above surface temperature and capable of providing the above pressure requirements to the nonwoven material / polymer film assembly.

[0028] and Figure 1 Similar to the situation in FIG. 1 , the application of heat and pressure causes the polymer resin in the film 14 to melt and now infuse into all or part of the upper dense nonwoven fiber layer 20 and / or nonwoven layer 12. Figure 2 .

[0029] It is also worth noting that from Figure 2 There are two preferred ways to form an acoustic composite from the precursor layers shown. In a preferred embodiment as described above, all of the layers shown can be formed into an acoustic composite by heating and pressurizing. Alternatively, the three-layer precursor of the nonwoven fiber layer 20, the polymer film layer 14, and the nonwoven fiber layer 12 can also be first heated and pressurized under a pressure range of 0.2psi to 10.0psi. Then, the lower nonwoven fiber layer 16 can be attached separately by additional heating. The attachment of the lower nonwoven fiber layer 16 can include adding a binder powder coating or a hot melt adhesive to the surface of the lower nonwoven fiber layer 16, and then heating to attach the nonwoven fiber layer 16 to the previously heated and pressurized nonwoven layer 20, the polymer film 14, and the nonwoven layer 12. The pressure here is preferably 0.5psi to 80.0psi.

[0030] The products obtained by any of the above methods can achieve selected adjustable airflow resistance and acoustic performance in the final product. This can be characterized by Rayls (MKS), which preferably ranges from 800 Rayls to 10,000 Rayls, including all values ​​and increments therein. More preferably, the Rayl value is in the range of 3000 Rayls to 900 Rayls (MKS). In this regard, Figure 2 The lower surface 22 of the nonwoven material / polymer film assembly shown in FIG. 1 may also be adhered to the inner surface of the vehicle sheet metal.

[0031] With regard to the representative acoustic composite production process herein, the upper nonwoven layer 12 is applied to the polymer film layer 14, which is applied to the lower nonwoven fiber absorber layer 16. The polymer film layer itself is preferably selected from a multilayer film, the melting points of the upper and lower layers of which are lower than the melting point of the middle layer. Then, the layer is preferably passed and preliminarily pressed in a hot contact surface with a surface temperature in the range of 350°F to 400°F for about 1.0 seconds to 20 seconds, even more preferably 10.0 seconds to 15.0 seconds. The purpose of doing so is preferably to melt the film layer and attach it to the nonwoven layers above and below the polymer film layer. Then, it can be cut into a certain size as needed, placed in a heated press plate, and pressed at a pressure of 1.0psi to 100psi and a temperature of 275°F to 450°F. Finally, the composite produced in this way is preferably placed in a cold mold, molded and cooled. The pressure of this step is also preferably 1.0psi and 100psi. The Rayl value (MKS) of the composite produced in this way is in the range of 800 and 10,000.

[0032] It should now be understood that the present invention can produce a relatively low cost acoustic layer for automobiles and provides adjustable acoustic performance measurements. By adjusting the thickness and basis weight of the nonwoven material and polymer film material and the heating and pressure profiles during the molding process, it is now possible to adjust the final product to the desired acoustic performance level. In addition, it should be noted that in the same mold, by applying different pressures to the starting nonwoven material / polymer film assembly, such as by adjusting the mold gap, etc., different airflow characteristics can be produced on the final molded composite, thereby developing different acoustic properties in the same molded composite part. Therefore, it can be understood that the composite produced herein can be formed so that it can be used as an acoustic absorber or play a role in transmission loss applications.

Claims

1. A method for forming an acoustic composite, the method comprising: a. Providing a layered structure having a thickness of 1.0 mil to 200.0 mils and a basis weight of 10 g / m 2 Up to 200g / m 2 The upper nonwoven layer has a thickness of 0.1 mil to 40.0 mils and a basis weight of 10 g / m 2 Up to 90g / m 2 A polymer film layer having a thickness of 75.0 mils to 4000.0 mils and a basis weight of 100 g / m 2 Up to 3000g / m 2 a lower nonwoven absorbent layer; b. Applying heat and pressure to the layered structure and forming the acoustic composite, wherein the acoustic composite exhibits an airflow resistance in Rayls (MKS) ranging from 800 to 10,000.

2. The method according to claim 1, characterized in that The upper nonwoven layer has a melting point, the polymer film layer has a melting point, and the lower nonwoven fiber absorbent layer has a melting point, and the melting points of the upper nonwoven layer and the lower nonwoven fiber absorbent layer are both greater than the melting point of the polymer film layer.

3. The method according to claim 1, characterized in that: The polymer film layer is a multi-layer material having an upper polymer film layer, a central polymer film layer and a lower polymer film layer.

4. A layered structure suitable for forming an acoustic composite for an automobile, the layered structure comprising: a. Thickness of 1.0mil to 200.0mils and basis weight of 10g / m 2 Up to 200g / m 2 an upper nonwoven layer; b. Thickness is 0.1mil to 10.0mils and basis weight is 10g / m 2 Up to 90g / m 2 A polymer film layer; and c. Thickness of 75.0 mils to 4000.0 mils and basis weight of 100 g / m 2 Up to 3000g / m 2 The lower nonwoven fiber absorbent body layer.

5. A method for forming an acoustic composite, the method comprising: a. Providing a layered precursor structure having an upper nonwoven layer having a thickness in the range of 55.0 mils to 800.0 mils and a basis weight of 400 g / m 2 Up to 2000g / m 2 ; A polymer film layer having a thickness of 0.1 mil to 40.0 mils and a basis weight of 10 g / m 2 Up to 90g / m 2 The intermediate nonwoven layer has a thickness of 1.0 mil to 200.0 mils and a basis weight of 10 g / m 2 Up to 200g / m 2 and a lower nonwoven fiber absorbent layer having a thickness of 75.0 mils to 4000.0 mils and a basis weight of 100 g / m 2 Up to 3000g / m 2 ;as well as b. applying heat and pressure to the layered structure and forming the acoustic composite, wherein the acoustic composite exhibits an airflow resistance in Rayls (MKS) in the range of 800 to 10,000.

6. The method according to claim 5, characterized in that The upper nonwoven layer, the middle nonwoven layer and the lower nonwoven layer each have a melting point, the polymer film layer has a melting point, and the melting points of the upper nonwoven layer, the middle nonwoven layer and the lower nonwoven layer are all higher than the melting point of the polymer film layer.

7. The method according to claim 5, characterized in that The polymer film layer is a multi-layer material having an upper polymer film layer, a central polymer film layer and a lower polymer film layer.

8. A method for forming an acoustic composite, the method comprising: a. Providing a three-layer precursor, the three-layer precursor having: an upper nonwoven layer, the thickness of the upper nonwoven layer is in the range of 55.0 mils to 800.0 mils and a basis weight of 400 g / m 2 Up to 2000g / m 2 ; A polymer film layer having a thickness of 0.1 mil to 40.0 mils and a basis weight of 10 g / m 2 Up to 90g / m 2 ; and an intermediate nonwoven layer having a thickness of 1.0 mil to 200.0 mils and a basis weight of 10 g / m 2 Up to 200g / m 2 ; b. heating and pressurizing the three-layer structure and forming a three-layer composite; and c. Providing a lower nonwoven fibrous absorbent layer having a thickness of 75.0 mils to 4000.0 mils and a basis weight of 100 g / m 2 Up to 3000g / m 2 , and attaching the lower nonwoven fibrous absorbent layer to the middle layer of the three-layer composite and forming the acoustic composite, wherein the acoustic composite exhibits an airflow resistance in Rayls (MKS) between 800 and 10,000.

9. A layered precursor structure suitable for forming an automotive acoustic composite, the layered precursor structure comprising: a. Thickness in the range of 55.0 mils to 800.0 mils and basis weight of 400 g / m 2 Up to 2000g / m 2 an upper nonwoven layer; b. Thickness of 0.1mil to 40.0mils and basis weight of 10g / m 2 Up to 90g / m 2 A polymer film layer; and c. Thickness of 1.0 mil to 200.0 mils and basis weight of 10 g / m 2 Up to 200g / m 2 The middle nonwoven layer.

10. The layered precursor structure of claim 9 further comprising a lower nonwoven fibrous absorbent layer attached to the middle nonwoven layer, the lower nonwoven fibrous absorbent layer having a thickness of 75.0 mils to 4000.0 mils and a basis weight of 100 g / m 2 Up to 3000g / m 2 .

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