PLASTIC COMPOSITE COMPONENT

Description

[0001] The invention relates to a plastic composite component, in particular a tube or ring in composite construction, according to the preamble of claim 1. State of the art

[0002] Today's competitive pressure forces companies to examine existing manufacturing processes and products for potential cost savings. Wherever possible, time-consuming and labor-intensive steps in the production of complex metal components are bypassed by simplifying products to enable automated manufacturing. There is also a trend to replace more expensive metal components with cheaper plastic parts. However, a problem with this is that the less expensive plastic parts very often fail to meet the required stability standards. For this reason, the plastic parts typically need to have greater wall thicknesses than their metal counterparts.

[0003] US2017 / 0204937A1 (D1) discloses an endless ribbon loop with a substantially uniform width. The ends of the endless ribbon feature interlocking splice formations. To manufacture the endless ribbon, a thermoplastic connector is attached between the exposed surfaces created by the splice formation at the ends of the endless ribbon. By definition, the exposed surfaces are those surfaces that are covered when the two ends are joined and include the end faces of the splice formation. After aligning the splice formation at both ends of the endless ribbon, a seamless and permanent connection is achieved by thermally processing the thermoplastic connector. The thermoplastic connector comprises a thermoplastic copolyester elastomer. The endless ribbon may have a top layer of polymer or thermoplastic elastomer.

[0004] WO2015 / 108074A1 (D2) describes an endless belt comprising a rubber layer with an embedded fiber fabric. A reinforcing fabric is attached to this rubber layer. The reinforcing fabric has finger-shaped projections at one end, which are arranged correspondingly at the other end. The finger-shaped projections at both ends interlock. This interlocking connection is heated and pressed using a press to achieve a permanent bond. An additional rubber layer can be applied to one or both sides of the endless belt. Applying this additional rubber layer also requires heating and pressing the endless belt to vulcanize the respective rubber layers.

[0005] WO2004 / 110738A2 (D3) discloses a method for joining two fiber composite laminates, wherein a first set of teeth is cut into the end of the first fiber composite laminate and a second set of teeth is cut into the end of the second fiber composite laminate, such that the second set is aligned interlocking with the first set of teeth. For cohesion of the two fiber composite laminates, adhesive is applied to the bond line formed by the mutual alignment of the fiber composite laminates and subsequently cured.

[0006] Components that must withstand high pressure are often reinforced with continuous fibers. For example, if pipes are subjected to high internal pressure, the majority of the fibers are wound circumferentially. However, pre-winding the pipes is time-consuming and therefore expensive. Consequently, there is a need for pipes, rings, and similar components that can withstand high pressure but can be manufactured cost-effectively. Object of the invention

[0007] Therefore, one objective of the present invention is to provide a component capable of replacing metal components. A further objective is to provide a component that can withstand high pressures. In particular, it is an objective to provide a tube or ring that can withstand the highest possible burst pressure. Description

[0008] According to the invention, the aforementioned objectives are achieved by the features of claim 1. Advantageous embodiments are defined in the dependent claims.

[0009] The invention relates to a plastic composite component, in particular a tube or ring in composite construction, with a wall comprising at least two layers, namely a first layer with a fiber fabric or woven material, wherein a butt joint is defined between two ends of the fiber fabric or woven material, and a second layer which is fully bonded to the first layer. The butt joint can be formed between two edges of different fiber fabrics or woven materials in the case of a non-round component, or between the ends of the same fiber fabric or woven material in the case of a round component, and is designed as a wedge- or finger-joint-like butt joint. The wedge- or finger-joint-like butt joint is characterized in that the two ends of the fiber semi-finished product forming the butt joints have finger-like projections that interlock.This has the advantage that the butt joint according to the invention exhibits a significantly higher tensile strength than one with a straight butt joint. The fiber fabric or woven material is used as a prefabricated semi-finished product. For the purposes of the invention, a prefabricated semi-finished product is understood to mean that the fiber fabrics or woven materials are cut and / or shaped in such a way that two edges abut each other or are very close to each other, i.e., separated from each other by a gap of 1 mm or less.

[0010] According to the invention, the plastic composite component is characterized by the fact that the continuous fibers embedded in the fiber fabric or woven fabric run at least partially perpendicular to the general direction of the butt joint between the two ends of the fiber fabric or woven fabric forming the butt joint. "Partially" means that at least 60% of the continuous fibers present in the fiber fabric or woven fabric are at least partially perpendicular to the general direction of the butt joint. Preferably, this proportion is at least 70%. More than 60% of the continuous fibers embedded in the fiber fabric or woven fabric run substantially parallel to each other and perpendicular to the general direction of the butt joint.

[0011] Advantageously, the length of the butt joint is increased by 100%, preferably by 200%, and particularly preferably by more than 300% compared to a straight butt joint. The longer the butt joint, the greater the increase in tensile strength perpendicular to the joint.

[0012] According to a particularly preferred embodiment, the semi-finished product is a fiber mat or woven fabric embedded in a plastic matrix. This has the advantage that commercially available organosheets can be used.

[0013] Advantageously, the fiber content by weight in such a semi-finished product is between 30% and 90%, preferably between 40% and 80%, and particularly preferably between 50% and 70%. Such semi-finished products are correspondingly very thin and have a low thickness.

[0014] However, it is also conceivable that the semi-finished product is a fiber mat or woven fabric arranged on a carrier material. Alternatively, the fiber mat used can also be held together by a number of weft threads in such a way that it can be cut and handled.

[0015] In terms of manufacturing, the appropriately cut fiber semi-finished product is placed in an injection mold and then overmolded. In the case of fiber semi-finished products embedded in a plastic matrix, the second layer is injection-molded onto the first layer of semi-finished product in an injection molding machine.

[0016] Fiber-reinforced fabrics or woven fabrics are advantageously used in which more than 75%, preferably more than 90%, of the continuous fibers embedded in the fabric or woven fabric run essentially parallel to each other and perpendicular to the general direction of the butt joint. The more fibers run perpendicular to the general direction of the butt joint, the greater the improvement in tensile strength.

[0017] A primary application of the fiber semi-finished products cut according to the invention is the production of tubes or rings, although the proposed wedge- or finger-joint-like butt joints can also be realized in principle with flat components. It is intended that the elasticity of the components made from the fiber semi-finished products cut according to the invention does not permit plastic deformation. A component made from the fiber semi-finished products cut according to the invention exhibits a rigid structure and high resistance to elastic deformation. At the same time, such a component cannot be bent under its own weight when unfastened.

[0018] Advantageously, the first layer, consisting of the semi-finished product, forms the outer layer of the wall of a tubular or sleeve-shaped component. This has the advantage that the fiber semi-finished product, in particular fiber-reinforced fabrics or woven fabrics already embedded in a plastic matrix, can be placed in an injection mold. It goes without saying that the fibers then run circumferentially between the two ends of the fiber-reinforced fabric or woven fabric that form the butt joint.

[0019] Advantageously, the semi-finished product has a thickness between 0.05 and 1 mm, preferably between 0.1 and 0.5 mm, and particularly preferably between 0.15 and 0.4 mm. Thicknesses between 0.2 and 0.3 mm have proven effective.

[0020] According to a preferred embodiment of the invention, an organosheet is used as the fiber semi-finished product. Organosheets are commercially available in various embodiments.

[0021] Advantageously, the tensile strength perpendicular to the butt joint is increased by at least 30 percent, preferably by at least 50 percent, and particularly preferably by at least 70 percent, compared to a component with a substantially straight butt joint. Glass, carbon, polyamide, or aramid fibers are preferably used.

[0022] Also disclosed is a method for manufacturing a plastic composite component of at least two layers, in particular a tube or ring in composite construction, comprising the following process steps: characterized by a. Providing a fiber mat or woven fabric, b. Cutting a fiber semi-finished product from the fiber mat or woven fabric, wherein two opposing ends are formed with protruding and spaced-apart fingers so that they can interlock when the fiber semi-finished product is placed in an injection mold, c. Placing the fiber semi-finished product in an injection mold such that the fingers interlock, and d. Overmolding the fiber semi-finished product with a curable plastic.

[0023] This method has the advantage of being significantly less complex than if a tube, ring or sleeve had to be wound with continuous fibers first.

[0024] In principle, instead of process steps a and b, the fiber semi-finished product can also be cut from a larger organosheet and then thermally pre-formed according to the injection mold to be used. A further plastic layer can then be injection-molded onto the organosheet placed in an injection molding device, whereby the plastic matrix of the fiber tape and the plastic to be injected must be compatible and preferably belong to the same plastic group.

[0025] Advantageously, a thermoplastic from the group consisting of polycarbonates, polyamides, polyphenylene sulfides (PPS), polysulfones, polyethylenes, polybutylene terephthalates or polyetheretherketones is used as the plastic, with polyamide 6 or polyamide 66 being preferred.

[0026] An independent aspect of the invention is the creation of the butt joint and the joining of the two layers without the use of any further element, such as a separate connecting element. This includes, among other things, the elimination of an additional adhesive.

[0027] An embodiment of the invention will now be described in more detail with reference to the following figures. It shows: Figure 1: A side view of a plastic composite component according to the invention in the form of a sleeve or a pipe section with a finger-joint or wave-shaped butt joint; Figure 2: An end view of the sleeve of Fig. 1 Figure 3: A cut and shaped thermoplastic fiber semi-finished product for use in the plastic composite component according to Fig. 1 ., which is spread apart to better illustrate the butt joint.

[0028] The Figures 1 to 3Figure 11 shows a plastic composite component 11 according to the invention in the form of a circular cylindrical tube section or a circular cylindrical sleeve 13. The sleeve 13 comprises an outer first layer 15 with a fiber fabric or woven material and a second layer 19, which is fully bonded to the first layer 15. In contrast to a wound tube, the fiber fabric or woven material has a joint 21, i.e., the continuous fibers have a fracture point in the circumferential direction. This fracture point is due to the manufacturing process, since the continuous fibers are not wound and a corresponding molded part produced, but rather a fiber semi-finished product is cut from a generally larger fiber fabric or woven material and used. A disadvantage of this technique is that a weak point of the component exists along the joint. If the component is subjected to high pressure, it will burst along the joint.

[0029] To mitigate this disadvantage, the invention proposes to form a wedge- or finger-joint-like butt joint 23 with finger-like projections 25. This has the advantage that the length of the actual butt joint is increased to several times that of a straight butt joint, which in this case would run in the longitudinal direction 25 of the sleeve. Surprisingly, this allows the tensile strength perpendicular to the general direction of the butt joint to be increased by more than 50%. In a pipe subjected to high internal pressure, this manifests itself in a significantly increased burst pressure.

[0030] If the first layer of fiber fabric or woven fabric has a certain initial thickness, then the second layer has a thickness between five and twenty times, and particularly preferably between seven and twelve times, of the first layer.

[0031] The invention relates to a plastic composite component, in particular a tube or ring in composite construction, with a wall comprising a first layer in which a semi-finished product with a fiber mat or woven fabric is inserted, wherein a butt joint is defined between two ends of the fiber mat or woven fabric. A second layer is fully bonded to the first layer. The composite component is characterized by the fact that the butt joint is designed as a wedge- or finger-joint-like butt joint. Compared to components with a straight butt joint, the component exhibits a significantly higher tensile strength. In the case of tubes, the burst pressure, measured according to DIN ISO 2758, is at least 50% higher than that of tubes with a fiber mat or woven fabric and a straight butt joint. legend

[0032] 11 Plastic composite component 13 Sleeve or pipe section 15 First layer 19 Second layer 21 Joint 23 Wedge or finger-joint-like butt joint 25 Finger-like projections 27 Longitudinal direction

Claims

1. A plastic composite component (11), in particular a tube or ring of composite construction, with a wall with a first layer (15) in which a semi-finished product with a fibre structure or fibre fabric is utilised, wherein a butt joint (21) is defined between two ends of the fibre structure or fibre fabric, and a second layer (19) which is connected to the first layer (15), wherein the butt joint (21) is formed as a wedge-like or interlocking finger-like butt joint, and at least portions of the continuous fibres embedded in the fibre structure or fibre fabric extend perpendicular to the general direction of the butt joint between the two ends of the fibre structure or fibre fabric forming the butt joint, characterized in that more than 60% of the continuous fibres embedded in the fibre structure or fibre fabric extend substantially parallel with respect to each other and perpendicular to the general direction of the butt joint.

2. The composite component as claimed in claim 1, characterized in that the length of the butt joint (21) is extended by 100%, preferably by 200% and particularly preferably by more than 300% compared with a straight butt joint.

3. The composite component as claimed in claim 1 or claim 2, characterized in that the semi-finished product is a fibre structure or fibre fabric embedded in a plastic matrix.

4. The composite component as claimed in one of claims 1 to 3, characterized in that the proportion by weight of fibres in the semi-finished product which is utilised is between 30% and 90%, preferably between 40% and 80% and particularly preferably between 50% and 70%.

5. The composite component as claimed in claim 1 or claim 2, characterized in that the semi-finished product is a fibre structure or fibre fabric disposed on a carrier material.

6. The composite component as claimed in one of claims 1 to 4, characterized in that the fibre structure which is utilised is cohered by a number of weft threads.

7. The composite component as claimed in one of claims 1 to 6, characterized in that the second layer (19) is moulded onto the first layer (15) with the semi-finished product in an injection moulding device.

8. The composite component as claimed in one of claims 1 to 7, characterized in that more than 75%, preferably more than 90% of the continuous fibres embedded in the fibre structure or fibre fabric extend substantially parallel to each other and perpendicular to the general direction of the butt joint.

9. The composite component as claimed in one of claims 1 to 8, characterized in that the plastic composite component is a tube (13) or ring.

10. The composite component as claimed in claim 8, characterized in that the first layer (15) with the semi-finished product forms the outer layer of the wall.

11. The composite component as claimed in one of claims 1 to 10, characterized in that glass fibres, aramid fibres or carbon fibres, wherein carbon fibres are preferred, are utilised as the fibres.

12. The composite component as claimed in one of claims 1 to 11, characterized in that the semi-finished product has a thickness of between 0.05 and 1 mm, preferably between 0.1 and 0.5 mm and particularly preferably between 0.15 and 0.4 mm.

13. The composite component as claimed in one of claims 1 to 12, characterized in that the semi-finished product is an organometallic sheet.

14. The composite component as claimed in one of claims 1 to 13, characterized in that the tensile strength perpendicular to the butt joint (21) is increased by at least 30 percent, preferably by at least 50 percent and particularly preferably by at least 70 percent compared with a component with a substantially straight butt joint.