Patent Application
20120034833
The invention relates to composite components made of heat-curing resins and elastomers according to the preamble of the independent claims.
The current prior art for producing composite components from a heat-curing resin with an elastomer layer consists in first producing a molding from heat-curing resin and applying the elastomer layer thereto in a new processing step. This system is currently used in the case of elastomer-coated rollers or cylinders as well as other multi-component moldings. The production and curing of the resin-based molding take place in autoclaves or hot presses at elevated temperature, wherein a reinforcing insert made of a woven fabric or fibrous materials can additionally be incorporated. In both processes the curing occurs by chemical reaction. For example, rollers, wheels, anti-slip coatings made of plastics material or elastomer articles provided with a certain inherent rigidity can be produced in this manner.
With use of plastic plates, for example in automotive construction or shipbuilding, elastomer profiled parts are fixed, for example glued on or screwed on, to the edges so as to create a seal and compensate for different coefficients of thermal expansion or so as to avoid warping and creaking in the event of resilient movements of the vehicles caused by travelling conditions.
Fiber-reinforced plastics are generally energy elastic and brittle and can therefore take on or absorb little energy in the event of an application of energy caused by vibrations, collisions, impacts or bombardment. This may lead to damage of the component, wherein sharp and jagged breaking edges occur which may cause injury. If necessary, specific measures must be taken to absorb energy and prevent damage to the component caused by resonances. Fiber-reinforced plastics are easily combustible owing to their resin content and, in the event of a fire, supply additional fuel thereto.
In WO 2006/122749 A1 the applicant has already described composite components, methods for the production thereof and some advantageous applications.
The object of the present invention is to describe further advantageously producible plastic composite components which are of increased customer benefit in different fields.
This object is achieved by the plastic composite components disclosed in the different independent claims. Advantageous embodiments of the invention are to be inferred from the respective dependent claims.
In accordance with the invention a hard layer is formed as a component surface from the heat-curing resin by chemical reaction, at the same time the elastomer layer provided with a cross-linking agent is also cured or vulcanized by chemical reaction, the direct bond between the elastomer layer and the hard layer is achieved, and lastly the connection to a plastics carrier layer arranged on the rear of the elastomer layer is formed.
A woven fabric insert, a fiber material or metal powder may be contained in one or more layers.
The terms “plastics outer layer” and “adjoining on the inside” are each considered from the side of use of the plastic composite component. In the case of an inner cladding part of a vehicle, the plastics outer layer is accordingly the layer facing the interior of the vehicle.
If the present invention refers to “layers”, this may mean strips, pieces or areas of the aforementioned materials arranged above one another or embedded in one another either completely or only in part.
Within the meaning of the present invention a plastic composite component is also referred to if one or more layers of the plastic composite component consist of metal or other materials not to be referred to as plastics.
The plastics carrier layer acting as a solid carrier and which can also optionally be supplemented or replaced by at least one metal carrier layer, the elastomer layer located thereon and the plastics outer layer are jointly assembled in a single processing step and are then cured or vulcanized jointly under the influence of heat in an autoclave or a hot press. All raw materials involved are adapted to one another in such a way that they simultaneously form a chemical network under identical reaction conditions and form a bond to one another. A dimensionally stable product is produced by these processes. The curing temperature is preferably between 80 and 200 ° C.
The assembly of the multi-component product made of heat-curing resin, the elastomer layer provided with a cross-linking agent and the metal and/or plastics carrier layer occurs in a number of alternatives as follows:
The anti-adhesive coating of the mold may be produced by paraffins, silicone, surfactants or fluorocarbons (for example Teflon).
The following may preferably be used as synthetic resins: polyester resins, phenol formaldehyde resins, cyanate ester resin, epoxy resins and acrylate resins.
The elastomer components which are not yet cross-linked but are provided with a cross-linking agent and the woven fabric inserts are laid directly in the mold at the corresponding locations during production of the fiber-reinforced plastic parts. The following may preferably be used as an insert in the composite product: glass fibers, nylon, polyester, carbon fibers, viscose, aramid fibers and/or metal fibers. The insert may be provided in the form of a woven fabric, a non-woven fabric or a pulp.
With use of a thermoplastic elastomer (TPE) for the elastomer layer in conjunction with a thermosetting plastics carrier layer, the TPE is optionally heated before being combined with the thermoset to a temperature in the vicinity of the softening point of the TPE. The TPE can thus be better draped over the thermoset. It can adapt better to the contour thereof and/or to the contour of a mold or die which is used for the production of the plastic composite component.
By introducing soft elastomer layers both a vibration absorption and a vibration insulation can be achieved by the selection of suitable materials. The spreading of cracks is inhibited, wherein the spreading of cracks is prevented in particular by a woven fabric, knitted fabric or a fiber structure made of high-performance fibers (such as aramid or Vectran®, registered mark of Kuraray Co., Ltd., JP) embedded completely in an elastomer material.
The spread of fire is impaired by the optional introduction of flame-resistant elastomer layers.
The production of an electrically conductive or radiation-screening variation is possible without significantly higher material costs caused by the embedding of conductive fibers, strips or woven fabric.
A particularly advantageous property of a plastic composite component according to the invention consists in that the plastic composite component absorbs energy and therefore can be used in all areas in which components have to be protected against mechanical energies and impulses or, vice versa, in which people or objects have to be protected against impacting composite components.
A further advantageous property of a composite component according to the invention consists in that the composite component exhibits improved crash behavior with the consequence of effective splinter protection to avoid injury and an avoidance of a sudden total failure of the composite component.
In the generic document WO 2006/122749 A1 already mentioned above, a wide range of advantageous applications for a plastic composite component according to the invention are already disclosed, but with no detailed indication of the layered structure which is particularly advantageous for the respective application or of the preferred field of application:
The generic document WO 2006/122749 A1 further mentions that a multi-layer structure is advantageous for specific applications, wherein a synthetic resin layer and an elastomer layer provided with a cross-linking agent advantageously alternate and wherein one or both outer layers are advantageously formed by synthetic resin. However, the sandwich construction may also be reversed if soft outer layers are desired, for example in the case of a table tennis bat, an inner cladding part of a vehicle or a mouse mat.
The advantages disclosed in the generic document WO 2006/122749 A1 also apply, in principle, to the plastic composite components described in the present application:
In principle it is also advantageous for the plastic composite components described in the present application if, as described in the generic document WO 2006/122749 A1, the elastomer layers contain at least 0.5 pph (parts per hundred) of at least one cross-linking agent from the group of peroxides, amines and/or bisphenols, and both the carrier layer and the elastomer layer can be interconnected by the influence of heat or another form of energy application in a single processing step, without the need for an adhesion promoter. Such cross-linking agents are not necessary with use of a thermoplastic elastomer (TPE), such as styrene/ethylene butene/styrene block copolymer (SEBS) or styrene/butadiene/styrene block copolymer (SBS) or a thermoplastic elastomer based on polyurethane (TPU) or a low-density polyethylene (LDPE) or styrene/butadiene rubber (SBR) with a styrene content of more than 50%.
The present invention widens the applications already proposed since at least one thin hard plastics outer layer made of synthetic resin and an elastomer layer adjoining the former are jointly connected using a metal and/or plastics carrier layer to form a plastic composite component, wherein the plastics carrier layer is formed of a fiber-reinforced plastic (FRP), a carbon fiber reinforced plastic (CRP) or a glass fiber reinforced plastic (GFP). Such an alternating “hard-soft-hard” layer structure has proven to be particularly advantageous for the plastic composite components disclosed in independent claims 1 to 3, wherein the key aspects of the three independent claims are three essentially different applications:
Of these three applications, at least two may overlap in some components. For example, in the case of a bumper or a bonnet of a vehicle, not only the active and passive safety of the passengers and any individuals colliding with the vehicle is important, but also a splinter-free deformation for absorbing the impact energy and a reduction in the impulse upon impact of small bodies (stone-chipping). However, bonnets also should not generate any droning noises caused by vibrations of the vehicle or the drive thereof, and therefore both the first two aspects and also the third aspect of vibration damping are important in this instance.
In a fourth application according to claim 33 the plastic composite component is formed of at least one thin hard plastics outer layer made of synthetic resin and an elastomer layer adjoining the former with a woven fabric, knitted fabric or fiber layer embedded therein. In this case the plastic composite component has bi-flexible properties, wherein the deflection in the event of an application of force from the elastomer side is stronger than in the event of application of an identical force from the synthetic resin side. In other words, in the event of an application of force from the synthetic resin side, the plastic composite component has a higher modulus of elasticity than in the event of an application of force from the elastomer side. This property opens up completely new applications in many technical fields. Examples include components loaded aerodynamically or hydrodynamically from different sides under different operating conditions, such as spoilers, airfoils, tail units, and valve membranes, which are exposed to compressive forces from one side and base drag forces from the other side and which, owing to their different deflection, control or assist specific functions (lift, downforce, leakiness in valves) merely by their material properties. Such a plastic composite component is also suitable for use as a hinge which can be bent preferably in one direction (specifically the bending direction with the lower modulus of elasticity).
A fifth field of application for a plastic composite component according to claim 34 made of at least one thin hard plastics outer layer made of synthetic resin, at least one elastomer layer and at least one woven fabric, knitted fabric or fiber layer is a flexible design provided in a defined area (articulation region) of the plastic composite component, which design enables a hinge-like movability of the adjacent areas of the plastic composite component. The flexible area of the plastic composite component is characterized in that at least one elastomer layer, optionally more elastomer layers and also optionally at least one woven fabric, knitted fabric or fiber layer are provided in said plastic composite component, whereas the other layers of the plastic composite component, in particular the synthetic resin layers are preferably omitted in this area. This fifth field of application also enables a large number of new applications in different technical fields. Examples include:
Depending on the layer structure with which the articulation region of the plastic composite component is formed, the articulation obtains one or more degrees of freedom:
In the aforementioned list the movability of the articulation increases from top to bottom. The lower layers thus do not form any limitation for layers above and can therefore be used in conjunction therewith.
In an embodiment which is advantageous for all applications, the plastics outer layer is formed of a woven fabric material which is already saturated with synthetic resin (prepreg). Alternatively, the plastics outer layer is formed or produced by means of the resin infusion method.
Alternatively, dry fibers (woven fabrics, non-woven fabrics or pulps) can be laid in an elastomer layer and then connect to the elastomer layer and optionally also to adjacent layers. A dry fiber layer embedded in the elastomer layer or TPE layer acts similarly to a film in a laminate glass panel: if the composite component breaks, it holds all the individual parts thereof together.
The plastics outer layer is preferably formed of a fiber-reinforced composite plastic (FRP, CRP, GRP), polyethylene (PE), in particular a high molecular weight polyethylene (HMW-PE, or ultra high molecular weight polyethylene—UHMW-PE) or polytetrafluoroethylene (PTFE). The surface of the plastics outer layer is therefore relatively hard and preferably also very smooth. The plastics outer layer and/or the plastics carrier layer may alternatively also be formed by an “organic sheet” or a thermoplastic polymer with an embedded long-fiber reinforcement or endless-fiber reinforcement. In this context, a fiber length of 2 mm to 50 mm refers to long fibers; endless fibers are understood by a person skilled in the art to be fibers with a fiber length over 50 mm (see DE 10 2007 036 660 A1). In particular, with use of an organic sheet as a plastics outer layer and/or as a plastics carrier layer the plastic composite component can be produced together with its other layers in a single processing step by pressing or thermoforming.
At least one woven fabric or a knitted fabric or a fiber structure is preferably embedded in the elastomer layer in such a way that the fibers thereof are surrounded completely by the elastomer, at least in the partial areas subject to particular stress. The embedding within the elastomer layer is produced so that the woven fabric or the knitted fabric or the fiber structure is arranged closer to the side of a tensile load or bending tensile load of the plastic composite component. The woven fabric material of the carrier layer preferably consists of glass fibers, nylon, polyester, carbon fibers, viscose, aramid fibers or metal fibers. The fibers may be arranged in the form of a woven fabric, a non-woven fabric or a pulp. Polyester resin, phenol formaldehyde resin, cyanate ester resin, epoxy resin or acrylate resin can particularly preferably be used as synthetic resin. In particular, the woven fabric or the knitted fabric or the fiber structure in such plastic composite components in which a splintering and sudden total component failure are to be avoided at all costs particularly preferably consist of a high-performance fiber such as aramid or Vectran® (registered mark of Kuraray Co., Ltd., JP).
Provided it does not consist of TPE, the elastomer layer contains a cross-linking system which, depending on the elastomer used, contains at least one cross-linking agent from the group of peroxides, amines and/or bisphenols and enables a reaction with the synthetic resin of the carrier layer. Alternatively to a heat treatment for a cross-linking of the elastomer layer with the synthetic resin of the carrier layer, another cross-linking treatment, for example with ultraviolet radiation (UV light) may also take place. Further elastomer layers, if necessary with different strength and hardness, can be applied to a first elastomer layer and are composed in such a way that they bond to the respective elastomer layer located therebeneath. The at least one elastomer layer particularly preferably consists of materials based on rubber. Alternatively, the at least one elastomer layer may also consist of a thermoplastic elastomer (TPE).
Embodiments of the invention are described hereinafter with reference to the drawings, in which:
The plastic composite component 10 illustrated in
The plastics outer layer 12 consists of one or two fiber layers which are saturated with liquid synthetic resin. The fiber layers of the plastics outer layer 12 saturated with synthetic resin may be formed as a prefabricated component in the form of a fiber mat saturated with synthetic resin (prepreg) or may be produced by the resin infusion method. The plastics outer layer 12 is preferably formed of a fiber-reinforced composite plastic (FRP, CRP, GRP) or polyethylene (PE), in particular a high-density polyethylene (HMW-PE—high molecular weight polyethylene or UHMW-PE—ultra high molecular weight polyethylene).
The elastomer layer 14 consists of one of the following substances:
ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), ethylene-acrylate rubber (EAM), fluorocarbon rubber (FCM), acrylate rubber (ACM), acrylonitrile-butadiene rubber (NBR), optionally mixed with polyvinyl chloride (PVC), hydrogenated nitrile rubber (HNBR), carboxylate-nitrile rubber (XNBR), hydrogenated carboxylate-nitrile rubber (XHNBR), natural rubber (NR), ethyl vinyl acetate (EVA), chlorosulfonyl-polyethylene rubber (CSM), chlorinated polyethylene (CM), butyl or halobutyl rubber, silicone rubber (VMQ, MVQ), fluorosilicone rubber (FVMQ, MFQ), chlorohydrin rubber (CO), epichlorohydrin rubber (ECO), polychloroprene rubber (CR), one-component polyurethane (PU) or a combination or a blend of the aforementioned substances. Alternatively, the at least one elastomer layer may consist of a thermoplastic elastomer (TPE).
Provided it doesn't consist of a thermoplastic elastomer (TPE), the elastomer layer 14 contains a cross-linking system which enables a reaction with the synthetic resin of the outer layer 12 and the plastics carrier layer 16. Depending on the elastomer used for the elastomer layer 14, the following materials from at least one of the groups of peroxides, amines and/or bisphenols are suitable as cross-linking agents:
The proportion of cross-linking agent or cross-linking agents in the elastomer material is approximately between 0.5 to 15 pph rubber (parts per 100 parts of rubber of the rubber mixture), but can also be considerably higher.
The plastics carrier layer 16 is preferably formed of at least one layer of a fiber-reinforced plastic (FRP), a carbon fiber reinforced plastic (CRP) or a glass fiber reinforced plastic (GRP). Alternatively or in addition, at least one layer of the plastics carrier layer 16 may also consist of another material, in particular of metal. As a further alternative, the plastics outer layer and/or the plastics carrier layer may also be formed of an “organic sheet”, or a thermoplastic polymer with an embedded long-fiber reinforcement or endless-fiber reinforcement.
In the embodiment shown by way of example in
In
The planar plastic composite component 10 illustrated in
The plastic composite component or splinter protection composite component 10 illustrated in
A further application for a plastic composite component or splinter protection composite component 10 according to the invention is illustrated by way of example in
Such plastic composite components 10 with a fiber structure 18 embedded in an elastomer layer 14 are also very effectively integrated in protective clothing as protection against injury caused by shots, stabs and impacts in the field of personal protection (bullet-proof vests, protective shields) and in the case of corresponding types of sport (fencing, horse-riding, motorbike racing, motocross, ice hockey), or incorporated into corresponding protectors.
A number of embodiments for planar plastic composite components 10 are illustrated in
In
In
In
The comments already made above for
The manner in which the energy F of mechanical or acoustic vibrations is absorbed in the plastic composite component 10 is illustrated in
In
A sealing lip 682 is preferably molded on the gripping region 68 and protects the inside of the shaft containing the pneumatic components arranged therein against dirt and dust. A hand protection 684 in the form of an outwardly drawn lip which protects the user's hands against injury is also preferably molded on the end of the gripping region 68 facing the tool 664.
It is essential that the vibrations produced by the tool 664 in response to contact with the material to be machined (stones, concrete, asphalt, tiles) are largely decoupled or dampened by the elastomer layer 64 so that the user holding the gripping region is spared these vibrations as far as possible.
The same design illustrated in
A plastic composite component 70 is shown in
If the layer made of glass fiber fabric 82, which depending on requirements may also be replaced by a carbon fiber fabric, aramid fiber fabric or Vectran® fabric (registered mark of Kuraray Co., Ltd., JP), is interrupted in the articulation region 80C or replaced by a woven fabric made of resilient fibers, a limited horizontal displacement of the right-hand rigid part 80B away from the left-hand rigid part 80B is also additionally possible. Provided the articulation region 80C is only formed by one or more elastomer layers 84 and/or 85, a limited torsional movement T of the right-hand rigid part 80B relative to the left-hand rigid part 80B into and out of the plane of projection is also additionally possible. The strongest limitation of the movability of the articulation 80C is provided when at least one thin synthetic resin layer (carbon prepreg layer 86 or glass prepreg layer 88) spans the articulation region 80C. Only one limited pivoting movement S of the right-hand rigid part 80B relative to the left-hand rigid part 80B is then still possible. In this instance the fifth application of the plastic composite component 80 approximates the fourth application of the plastic composite component 70 according to
Plastic composite components 100 in which, according to
Compared to other known plastic composite components in which an extremely light core layer with a sandwich structure comprising spacers between two cover layers (honeycomb structure, for example made of cellulose or card) is used, the weight of the core layer 104 according to the invention made of an elastomer is higher; however the plastic composite component 100 according to the invention with the core layer 104 made of an elastomer affords considerable advantages compared to these extremely light composite components in terms of the impact behavior and vibration protection or damping behavior with regard to component vibrations. Owing to the integration of high-performance fibers into the neutral elastomer layer, a splinter protection can additionally be integrated.
The effective surfaces of a plastic composite component according to the invention can easily be adapted to the desired application, wherein in contrast to known composite components a connection of all layers is produced in a single processing step. The effective surface of the plastic composite material can be formed by the smooth, hard and scratch-resistant plastics outer layer, where minimal friction and good sliding properties (for example in the case of skis or snowboards), aerodynamic or hydrodynamic properties (for example in the case of airfoils or fuselages/hulls of air- or watercraft), protection against erosion, corrosion, abrasion and weathering (for example in the case of helicopter blades or wind wheels, in the case of external panels or external cladding parts of buildings or vehicles), or an avoidance of an adhesion of media or foreign bodies (for example in the case of containers of stirring devices, swimming pools or sewage treatment plant basins or in the case of ship hulls) are important.
By contrast, the effective surface of a plastic composite component according to the invention can be provided with a friction-increasing, soft layer made of an elastomer or TPE if said component requires a surface feel (for example gripping parts, steering wheels, switches and other operating elements) or anti-slip properties (for example surfaces of surfboards, internal cladding of freight holds, step plates in the entry and exit regions of vehicles).
A further field of application for a plastic composite component according to the invention is walls of fluid-guiding containers or pipelines. Owing to the embedded elastomer layer, such containers or tubes exhibit excellent protection against bursting. In particular in conjunction with a flame-resistant provision, such pipes and containers are best suited, for example, for the storage and guidance of chemically aggressive or highly explosive fluids. An additional coating formed of a rubber or rubber-like elastomer arranged on the medium-guiding side ensures the necessary media resistance of such containers or lines. Possible fields of application are fuel or oil tanks in all types of vehicle, in particular also in aircraft, helicopters or ships, also for military applications, pressurized air containers or lines, or tanks and lines for water, juices, other drinks, milk products or other foodstuffs, wherein a thermoplastic elastomer (TPE) is particularly well suited as a coating on the medium-guiding side.
The plastic composite component 10, 22, 42, 50, 60, 70, 80 or 100 with the plastics outer layer 12, 62, 72, 86 or 106 and the metal or plastics carrier layer 16, 66 or 88 as well as the elastomer layer 14, 64, 74; 84, 85 or 104 arranged therebetween is produced by being subjected to a treatment by way of an application of energy. For example, this may take place by a heat treatment in an oven, an autoclave, a heated press or a heated thermoforming die, a microwave system, a high-power light radiation system and/or a heatable table. The process temperature lies in the range of approximately 80 degrees Celsius to approximately 200 degrees Celsius, preferably at approximately 130 degrees Celsius. The duration of the process is approximately 5 hours. However, the duration of the process may vary within the given temperature range from approximately 10 minutes to approximately 8 hours depending on customer requirements. Alternatively, the plastic composite component 10 is subjected to another cross-linking treatment, for example with UV light. The at least one elastomer layer 14 cross-links with the synthetic resin of the plastics outer layer 12 and the plastics carrier layer 16. The plastics outer layer 12, the plastics carrier layer 16 and the elastomer layer or elastomer layers 12 are then bonded to one another in a non-detachable manner.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2009 005 438.1 | Apr 2009 | DE | national |
| 20 2009 006 966.4 | May 2009 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP10/02293 | 4/14/2010 | WO | 00 | 10/11/2011 |
