COMPOSITE ARTICLES WITH NATURAL FIBER INNER LAYER AND INJECTION-MOLDED OUTER LAYER

Abstract

A composite article (10) comprising: an inner layer (20) comprising a natural fiber; and an outer layer (22) injection-molded onto the inner layer (20), the outer layer (22) forming an outer surface over the inner layer (20), wherein the inner layer (20) comprises an outer side (26) and an inner side (28), wherein the outer layer (22) is injection-molded to the outer side (26) of the inner layer (20), wherein the composite article (10) further comprises a structure (30) injection-molded to the inner side (28) of the inner layer (20), wherein the structure (30) is formed from a polymer and comprises structural elements (32) separated by a hollow space (36), wherein the outer layer (22) forms a continuous surface over the inner layer (20), wherein the structural elements (32) are connected to one another by a honeycomb or hexagonal structure.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a composite article having a base layer made of a natural fiber and an injection-molded layer formed on the base layer. INTRODUCTION

[0002] Surfaces in automotive interiors can be formed in a variety of ways. Some examples use injection-molded surfaces. While such injection-molded surfaces can be formed with an aesthetically pleasing "Class A" finish, a minimum thickness is often required to achieve a desired stiffness.

[0003] In other examples, a mat may be provided with a natural fiber as the base material, but such a material may not have a sufficiently pleasing aesthetic surface, and additional structure may be required to ensure sufficient strength. To achieve a more desirable appearance, a skin may be placed over the mat to provide a sufficiently aesthetic surface, and one or more structural elements may be attached to a backing of the mat to increase stability. The resulting interior surface part has a certain thickness and complexity.

[0004] DE 10 2017 131 048 A1 relates to a method for producing a plastic component having at least one visible side with a painted surface at least on the visible side, wherein at least one insert, preferably containing reinforcing fibers and / or foamed, is inserted into an injection molding tool.

[0005] DE 10 2015 224 952 A1 relates to a method for producing an injection-molded component comprising a thermoplastic fiber-plastic composite. The thermoplastic fiber-plastic composite comprises a plastic matrix embedding a reinforcing fiber, which becomes more deformable as the temperature increases. The presentation "Dr. W. Klusmeier, N. Bogdanov: Use of natural fibers in the interior of a car - status and development, FNR, Wolfsburg, October 11, 2012" also refers to the use of natural fibers in the interior of a car. DESCRIPTION

[0006] The object of the invention is to provide a more stable composite article. This object is achieved by the subject matter according to claim 1. Further developments can be found in the subclaims.

[0007] The present disclosure provides a composite article including a natural fiber inner layer and an injection-molded layer overmolded over the inner layer to create an aesthetically pleasing surface. The combination of the natural fiber-containing inner layer and the injection-molded outer layer can also provide sufficient rigidity so that the entire composite article can be thinner than previous vehicle interior panels.

[0008] In one example, which may be combined or separated with other examples provided herein, a composite article includes an inner layer made of a natural fiber and an outer layer molded onto the inner layer. The outer layer forms an exterior surface over the inner layer.

[0009] In another example, which may be combined or separated from other examples provided herein, an unclaimed method of forming a composite article is provided. The method includes providing a base layer comprising a natural fiber. The method also includes providing a first tool and a second tool, the first and second tools configured to cooperate to form a cavity therebetween, and the first tool forming an injection molding channel therein. The method includes inserting the base layer into the cavity between the first and second tools and pressing the base layer into a desired shape. The method further includes flowing a liquid polymeric material through the injection molding channel of the first tool and onto a surface of the base layer to form an injection molded layer of the polymeric material on the base layer.

[0010] Optionally, additional features may be provided, including, but not limited to, the following: the outer surface or exterior of the injection-molded layer has a Class A finish; the natural fiber comprises hemp, jute, and / or kenaf; the outer layer (or injection-molded layer) comprises a polymer, such as polypropylene, polyetheretherketone (PEEK), and / or thermoplastic olefin (TPO); wherein the inner layer (or base layer) further comprises a polymer; wherein the inner layer (or base layer) is provided as a mat formed from a blend of about 50% by weight of a polymer and about 50% by weight of a natural fiber.-% of the natural fiber; wherein the inner layer (or base layer) is formed from a mat of the natural fiber and a polymeric spray coating disposed on the mat; wherein the outer layer (or injection-molded layer) is injection-molded to an outer surface of the inner layer (or base layer); a structure injection-molded to an inner surface of the inner layer (or base layer); wherein the structure is formed from a polymer and comprises structural elements separated by a cavity; the outer layer (or injection-molded layer) forming a continuous surface over the inner layer (or base layer); wherein the composite article forms a portion of the interior of a motor vehicle; wherein the composite article is a door bolster or a door card pocket; wherein the method further comprises compressing the injection-molded layer and the base layer together to reduce a thickness of the base layer.

[0011] The outer layer (or injection-molded layer) may have a thickness in the range of approximately 1.0 mm to approximately 2.5 mm, and the inner layer (or base layer) may have a thickness in the range of approximately 1.2 mm to approximately 2.5 mm. In some examples, the outer layer has a thickness of approximately 1.0 mm and the inner layer has a thickness of approximately 1.2 mm, resulting in a total part thickness of 2.2 mm.

[0012] The foregoing features and advantages, as well as other features and advantages of the present disclosure, will become apparent from the following detailed description when taken in conjunction with the accompanying figures and appended claims. BRIEF DESCRIPTION OF THE CHARACTERS

[0013] The figures described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. The components in the figures are not necessarily scalable, but emphasis is placed on illustrating the principles of this disclosure. In the figures: Fig. 1 is a perspective view of a vehicle door having a composite article according to the principles of the present disclosure; Fig. 2 is a cross-sectional view of the assembled article of Fig. 1, according to the principles of the present disclosure; Fig. 3 is a perspective view of a back of another variation of the Fig. 1-2 according to the principles of the present disclosure; Fig. 4 is a cross-sectional view of the variation of the Fig. 3 according to the principles of the present disclosure; Fig. 5 is a block diagram illustrating a method of making a composite article according to the principles of the present disclosure; Fig. 6 is a schematic side sectional view showing illustrations of steps of the Fig. 5 according to the principles of the present disclosure; Fig. 7 is a schematic side sectional view showing illustrations of additional steps of the Fig. 5 according to the principles of the present disclosure; and Fig. Figure 8 is a schematic side sectional view showing further additional steps of the Fig. 5 according to the principles of the present disclosure. DETAILED DESCRIPTION

[0014] The following description is merely exemplary in nature and is not intended to limit the present disclosure or its application or uses.

[0015] Referring to the figures, wherein like reference numerals refer to like elements, Fig. 1 shows a vehicle door 10 including a door pad 12 attached thereto. A map pocket 14 is also attached to the door 10 or formed integrally with an additional interior structure 16 of the door 10.

[0016] With reference now to Fig. 2, with further reference to Fig. 1, the door pad 12 is formed from a composite article 18. Although the composite article 18 is molded into the door pad 12, it should be understood that the composite article 18 may also be molded into the map pocket 14, other vehicle interior trim, or any other desired article.

[0017] The composite article 10 includes an inner layer or base layer 20. The base layer 20 is made of a natural fiber. For example, the base layer 20 may include hemp, jute, and / or kenaf, or any other desired natural fiber. The base layer 20 may also include a polymer. In some examples, the base layer 20 is a thermoplastic formed from a mat formed from a blend of about 50% of a natural fiber and about 50% of a polymer. In other examples, the base layer 20 is a thermoset layer formed from a natural fiber mat with a polymeric spray coating on the mat.

[0018] The composite article 10 also includes an outer layer 22 that is molded onto the inner or base layer 20. The outer layer 22 forms an outer surface 24 over the inner layer 20, which preferably has a Class A finish. The Class A finish of the outer surface 24 provides an aesthetically pleasing appearance to the vehicle interior. The injection-molded outer layer 22 is preferably formed from a polymer such as polypropylene, polyetheretherketone (PEEK), or thermoplastic olefin (TPO), or mixtures thereof. The inner layer 20 has an outer surface 26 and an inner surface 28. The outer layer 22 is injection-molded on and over the outer surface 26 of the inner layer 20. In the illustrated example, the outer layer 22 forms a continuous surface 24 over the inner layer 20 that adheres to the inner layer 20.

[0019] The composite article 18 with the two layers 20, 22 made of the materials described above results in a panel with sufficient rigidity that still has an aesthetically pleasing outer surface 24, without the composite article 18 having excessive thickness. For example, the outer layer 22 can have a thickness t1 in the range of about 1.0 mm to about 2.5 mm, and the inner layer 20 can have a thickness t2 in the range of about 1.2 mm to about 2.5 mm. Thus, the total thickness u of the composite article 18 can be in the range of about 2.2 mm to about 5 mm. Therefore, the total thickness u at the lower end of this range is thinner than other vehicle interior panels commonly used in the industry.

[0020] With reference to the Fig. 3-4 shows a variant of the back of the composite article. To distinguish each previously Fig. 1-2 shown element with a primary symbol or ' because the elements are the same as previously shown, but an additional structure on the back of the composite article 18' of the Fig. 3-4. Thus, the composite article 18' optionally includes a structure 30 injection-molded onto the inner side 28' of the inner layer 20' of the composite article 18'.

[0021] Like the outer layer 22', the structure 30 may be formed of a polymer such as polypropylene, polyetheretherketone (PEEK), or thermoplastic olefin (TPO). The structure 30 may provide additional structural support for the composite article 18'. In the illustrated example, the structure 30 includes a plurality of structural elements 32 that contact and adhere to the inner surface 28' of the base layer 20', and the structural elements 32 are interconnected by a honeycomb or hexagonal structure 34. The structural elements 32 are separated by a cavity 36 therebetween, such that in this example the structural elements 32 do not form a continuous surface over the inner surface 28' of the base layer 20'. However, it should be understood that in other examples, the structure 30 could be formed similarly to the outer layer 22' such that it could form a continuous surface over the base layer 20'.

[0022] With reference to the Fig. 5-8, steps for carrying out an exemplary method for forming the composite article 18, 18' are shown. In Fig. 5 shows a block diagram of the steps of the exemplary method 40, and in Fig. 6-8 are illustrations of elements, including optional elements, of the method 40.

[0023] The method 40 includes a step 42 for providing the base layer 20, 20', which includes the natural fiber material. The base layer 20, 20' can be provided with an initial thickness t0. In some variations, the initial thickness t0 can range from about 12 to about 15 mm.

[0024] As described above, the base layer 20, 20' may include a thermoplastic or thermosetting mat. In a thermoplastic variant, the mat may be formed from a blend of about 50% natural fiber and about 50% polymer. In a thermosetting variant, a polymeric spray coating may be applied to a natural fiber mat.

[0025] The method 40 also includes a step 44 for providing a first tool 46 and a second tool 48, wherein the first and second tools 46, 48 are configured to cooperate and form a cavity 50 therebetween. The first tool 46 has an injection molding channel 52 formed therein, which is used to form the molded outer layer 22, 22'. The second tool 48 may also have a channel (not shown) for injection molding to form the Fig. 3-4. Before inserting the base layer 20, 20' into the tools 46, 48, one or more heating elements 56 can be used to heat the base layer 20, 20'. For example, non-contact infrared heat can be used to heat the base layer blank 20, 20'.

[0026] With reference to Fig. 7, the method 40 further includes a step 54 of inserting the base layer 20, 20' between the first and second tools 46, 48 into the cavity 50 and pressing the base layer 20, 20' into a desired shape. The method 40 includes a step 58 of flowing a liquid polymeric material 60 through the injection molding channel 52 of the first tool 46 and onto a surface 26, 26' of the base layer 20, 20' to form an injection-molded layer 22, 22' of the polymeric material on the base layer 20, 20'. The liquid polymeric material 60 cures and forms the injection-molded layer 22, 22', which adheres to the surface 26, 26' of the base layer 20, 20'.

[0027] The method 40 may further include compressing the injection-molded layer 22, 22' and the base layer 20, 20' to reduce a thickness of each of the layers 20, 20', 22, 22'. For example, the base layer 20, 20' may be compressed from the initial thickness t0 to a resulting thickness t2, and the injection-molded layer 22, 22' may be compressed to a thickness of t1 before or during cooling of the overmolded material 60. The method 40 may optionally also include forming a Class A surface on an outer side 24, 24' of the injection-molded layer 22, 22'.

[0028] With reference now to Fig. 8, the tools 46, 48 can then be separated, and the finished composite article 18, 18' can be ejected from the tools 46, 48. Excess material 60 can be trimmed after the composite article 18, 18' has been ejected. The composite article 18, 18' can then already have a finished Class A surface, except that the outer surface of the composite article 18, 18' can be polished to remove the excess material 60 from the composite article 18, 18'.

[0029] Although in the Fig. 5-8, the method 40 may, if desired, further comprise injection molding a structure 30 on the inner side 28' of the inner layer 20', as described above with respect to the Fig. 3-4, by passing molten material through a channel formed within the second tool 48.

[0030] Although this is in the Fig.5-8 may be used to form the composite article 18, 18', it is to be understood that alternative methods of forming the composite article 18, 18' may be used without exceeding the spirit and scope of the present disclosure.

[0031] The description of the disclosure is merely exemplary in nature, and variations that do not depart from the gist of the disclosure are intended to be within the scope of the disclosure. Such variations should not be considered a departure from the spirit and scope of the disclosure.

Claims

[1] A composite article (10) comprising: an inner layer (20) comprising a natural fiber; and an outer layer (22) injection-molded onto the inner layer (20), the outer layer (22) forming an outer surface over the inner layer (20), wherein the inner layer (20) comprises an outer side (26) and an inner side (28), wherein the outer layer (22) is injection-molded to the outer side (26) of the inner layer (20), wherein the composite article (10) further comprises a structure (30) injection-molded to the inner side (28) of the inner layer (20), wherein the structure (30) is formed from a polymer and comprises structural elements (32) separated by a hollow space (36), wherein the outer layer (22) forms a continuous surface over the inner layer (20), wherein the structural elements (32) are connected to one another by a honeycomb or hexagonal structure. [2] The composite article (10) of claim 1, wherein the outer surface has a Class A finish, wherein the outer layer (22) comprises a polymer, preferably selected from the group consisting of polypropylene, polyetheretherketone (PEEK), and thermoplastic olefin (TPO), and the natural fiber comprises at least one selected from the group consisting of hemp, jute, and kenaf, wherein the inner layer further comprises a polymer. [3] The composite article (10) of any preceding claim, wherein the inner layer (20) is a mat formed from a mixture of about 50% by weight of a polymer and about 50% by weight of the natural fiber, the outer layer (22) having a thickness in the range of about 1.0 mm to about 2.5 mm, and the inner layer having a thickness in the range of about 1.2 mm to about 2.5 mm. [4] The composite article (10) of claim 1 or claim 2, wherein the inner layer (20) is formed from a mat of the natural fiber and a polymeric spray coating disposed on the mat, the outer layer (22) having a thickness in the range of about 1.0 mm to about 2.5 mm and the inner layer having a thickness in the range of about 1.2 mm to about 2.5 mm. [5] The composite article (10) according to any one of the preceding claims, which forms a portion of the interior of a motor vehicle, preferably a portion of a door pad or a door card pocket.

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