Patent Application
20230300988
The invention is directed to a method for producing an elastomeric component, preferably an elastomeric sealing component, comprising an elastomer body and a printed structure, preferably a printed electronic structure or circuit. The invention further relates to an elastomeric component obtained by said method.
Printing technologies for electronic structures and architectures on different substrates are known. However, if the structures should be printed on a rubber-like substrate with elastomeric properties such as thermoset elastomers, many problems arise, because vulcanized rubber exhibits non-uniform or non-homogenous surface properties. In addition, surface roughness and poor wettability of rubber substrates antagonize good printing results.
DE102008006390 describes a method for gluing flexible circuit boards consisting of layers of copper (electrical conductor) and polyimide (electrical insulator) to a reinforcement plate for complete stiffening or stiffening of desired regions of the circuit board. The method uses heat activated films based on a mixture of reactive resins forming a high-strength three-dimensional polymer network and on elastomers having long lasting elastic properties. The reinforcement plate may be of polymer material, such as polyester, polyethylene terephthalate, polyimides, polyethylene naphthalate or liquid crystal polymers.
The prior art however does not provide a method for efficient manufacturing of an elastomeric component, preferably sealing components, with a printed structure on its surface.
It is hardly possible to directly print fine structures on rubber substrates that do not have a perfectly planar surface, and even more, if the electronic structure should be printed on three-dimensional surfaces. The printing would be very difficult and slow.
Accordingly, there is a need for a workable and cost-efficient method to apply electronic structures to elastomeric substrates.
It is an objective of the invention to provide a workable and cost-efficient method for producing elastomeric sealing components, with printed structures, e.g. electronic structures or circuits.
At least one of the objectives of the present invention is achieved by a method according to claim 1. The method for producing an elastomeric component, preferably an elastomeric sealing component, comprising an elastomer body and a printed structure, preferably a printed electronic structure or circuit, on a surface of the elastomer body, comprises the steps of: a.) providing a planar foil of thermoplastic material having a printable surface, b.) printing a structure onto the printable surface of the planar foil to obtain the printed structure, c.) providing an elastomer substrate for forming the elastomer body (4) of the elastomeric sealing component; d.) placing the planar foil with the printed structure on the elastomer substrate, and e.) laminating the combined planar foil and elastomer substrate by applying heat and pressure; wherein the elastomeric component is obtained in that: (i) the elastomer substrate of step c) is formed to the shape of the elastomer body (4) of the elastomeric component before step d); or (ii) the elastomer substrate of step c) is formed to the shape of the elastomer body (4) of the elastomeric component during the lamination step e); or (iii) the elastomer substrate of step c) is formed to the shape of the elastomer body (4) of the elastomeric component after the lamination step e).
In the context of the present invention the elastomeric component is a technical component of a device or an object having elastic properties. In other words, its main function is based on the elasticity of the component at least in certain relevant regions of the component and the printed structure or the foil carrying the printed structure does not impair the function of the elastomeric component.
In a further embodiment, the foil may have elastomeric or elastic properties as well, and the printed structure is at least stretchable without forming cracks when stretched. The elastic properties of the foil may be in the same range as the elastomeric or elastic properties of the elastomer body. Alternatively, the foil including the printed structures may be arranged in regions of the elastomeric component, where the elastomeric properties of the elastomeric component are not used for its proper functioning. In this case, the foil may be flexible without having elastomeric properties and the printed structures do not need to be stretchable.
An elastomeric sealing component is understood as technical component of a device or an object that provides a seal of the device or object. In other words, the sealing component forms a seal against a fluid. Such sealing components are known in the art and a non-limiting list of examples is: a sealing gasket, a sealing membrane, a dosing membrane, a closure, a stopper or a plug (e.g. of a vial), an elongated sealing profile, a seal for a plunger (e.g. of a syringe). The elastomer body is understood as the part of the elastomeric sealing component, which defines the overall shape of the sealing component and is made of an elastomer substrate providing elastomeric properties to the elastomeric sealing component. The elastomer body forms the actual sealing component as listed above.
With the above method it becomes possible to apply printed structures, e.g. electronic structures or circuits, to rubber substrates which often have non-printable surfaces. In addition, the printed structure may be applied even to 3-dimensional surfaces of the rubber substrate, allowing for more versatile shapes and forms of the desired elastomeric sealing component. Another advantage is, that no additional adhesion layer or heat-activatable foil is required for gluing, due to the direct bonding between foil and substrate. Through the 2-step process, one is capable of printing on a planar, 2-D substrate and then in a second step place the printed structure on a 3-D-shaped elastomer object before lamination. Thereby, a variety of applications can be served with additional electronic functionalities. Alternatively, the foil with the printed structure may be placed on a planar surface of a preform of the elastomer object and formed into an object with a 3-D surface during the lamination step or after the lamination step.
The foil with the printed structure may be cut to leave a small rim surrounding the printed area of the foil having a width sufficient for proper bonding to the elastomer substrate. Such a rim may be especially useful when the printed structure is facing the surface of the substrate.
The printed structure may be printed with conductive and/or non-conductive (e.g. dielectric) ink to obtain printed electronic structures or circuits. The structures may be printed using known printing technologies such as screen printing, flexographic printing, gravure printing, relief printing, inkjet printing, piezo-inkjet printing, aerosol jet printing, stencil printing, offset printing, doctor blade printing, rotary screen printing, intaglio printing, digital printing, capillary printing, electrohydrodynamic printing, tampography, microcontact printing, laser printing.
The structures may be further connected to electronic components placed and attached to the planar foil. The structures may be e.g. a sensor or an antenna.
The planar foil may have a thickness in the range of 10 to 1000 micrometres, preferably to 75 micrometres.
A particularly efficient method is to provide a foil with a plurality of printed structures for individual elastomeric sealing components. The foil with the plurality of printed structures may be placed on the elastomer substrate in the form of a sheet. After or during lamination of the foil and the elastomer sheet individual elastomeric sealing components are produced by forming the elastomer body from the elastomer substrate and cutting out the individual elastomeric sealing components.
Further embodiments of the invention are set forth herein.
In some embodiments, the heat and pressure treatment during the laminating step d) may create chemical bonding, in particular covalent bonds, between the foil and the body. At the same time, the planar foil may be adapted to the 3-dimensional surface of the elastomer substrate of the elastomer body. The temperature used for laminating may be in the range of 120° C. to 160° C. Processing times of less than 60 seconds can be achieved for the lamination.
In some embodiments, the surface of the elastomer substrate of the elastomer body may be modified to achieve better bonding between the foil and the elastomer body before the laminating step e). Therefore, the surface may be subjected to plasma or corona treatment, without the use of additional bonding agents. Such surface treatment increases the bonding ability between foil and elastomer substrate of the elastomer body. Alternatively, a bonding agent only may be applied.
In some embodiments, the printed structure may be cured and/or dried after the printing step b) and before step d) is performed.
In some embodiments, after the printing step b) the printed structure is protected with a second foil of the same material as the planar foil or coated with a dielectric layer of dielectric ink or lacquer.
In some embodiments, the planar foil may be placed on the elastomer substrate of the elastomer body such that the printed structure faces the elastomer body. Alternatively, the planar foil may be placed on the elastomer substrate of the elastomer body such that the printed structure faces away from the elastomer body.
In some embodiments, the elastomer substrate of the elastomer body is made of a thermoset elastomer or a thermoplastic elastomer. The elastomeric material can be, for example, a synthetic or natural rubber, such as butyl rubber, isoprene rubber, butadiene rubber, halogenated butyl rubber (e.g., bromobutyl rubber), ethylene propylene terpolymer, silicone rubber, fluoro- or perfluoroelastomers, chlorosulfonate, polybutadiene, butyl, neoprene, nitrile, polyisoprene, buna-N, copolymer rubbers such as ethylene-propylene (EPR), ethylene-propylene-diene monomer (EPDM), acrylonitrile-butadiene (NBR or HNBR) and styrene-butadiene (SBR), blends such as ethylene or propylene-EPDM, EPR, or NBR, combinations thereof. The term “synthetic rubbers” also should be understood to encompass materials which alternatively may be classified broadly as thermoplastic or thermosetting elastomers such as polyurethanes, silicones, fluorosilicones, styrene-isoprene-styrene (SIS), and styrene-butadiene-styrene (SBS), as well as other polymers which exhibit rubber-like properties such as plasticized nylons, polyolefins, polyesters, ethylene vinyl acetates, fluoropolymers, and polyvinyl chloride.
In some embodiments, the planar foil may be made of a material selected from thermoplastic polyurethane (TPU), liquid silicone rubber (LSR), fluoropolymer (e.g. tetrafluoroethylene resin (PTFE), tetrafluoroethylen-perfluoroethylene copolymer (PFA), tetrafluoroethylene-hexafluoroethylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ATFE), polytrichlorotrifluoroethylene (PCTFE), polyfluorinated vinylidene (PVDF), polyfluorinated vinyl (PVF)), ultra-high-molecular-weight polyethylene (UHMW-PE), or an expanded fluoropolymer based foil. E.g. a TPU foil may adapt to the mechanical properties of the elastomer body, such as flexibility, stretchability and elasticity. The material of the printed structure may be accordingly chosen from stretchable materials, such as stretchable inks or pastes.
In some embodiments, the planar foil may be further provided with electronic components connected to the printed structure, before it is placed on the elastomer body.
In some embodiments, the surface of the elastomer substrate of the elastomer body for applying the electronic structure or circuit may be non-planar before the laminating step e) or is formed into a non-planar surface during the laminating step e).
The invention further relates to an elastomeric sealing component, preferably manufactured by the above method, comprising an elastomer body formed from an elastomer substrate and a thermoplastic foil laminated to a surface of the elastomer substrate for forming the elastomer body, the thermoplastic foil comprising a printed structure, preferably a printed electronic structure or circuit, on a printable surface of the foil.
In some embodiments, the elastomer substrate for forming the elastomer body may be made of a thermoset elastomer or a thermoplastic elastomer. The material may be selected from the materials described above.
In some embodiments, the thermoplastic foil may be made of a material selected from thermoplastic polyurethane, liquid silicone rubber (LSR), fluoropolymer (e.g. tetrafluoroethylene resin (PTFE), tetrafluoroethylen-perfluoroethylene copolymer (PFA), tetrafluoroethylene-hexafluoroethylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ATFE), polytrichlorotrifluoroethylene (PCTFE), polyfluorinated vinylidene (PVDF), polyfluorinated vinyl (PVF)), ultra-high-molecular-weight polyethylene (UHMW-PE), or an expanded fluoropolymer based foil.
In some embodiments, the printed structure may be arranged on a non-planar surface of the elastomer body.
The described method is not only applicable to the production of elastomeric sealing components but also to other elastomeric products or elastomeric components such as elastomeric sensor pads or elastomeric soft and dry electrodes for medical devices, or to elastomeric tubes for conducting fluids, or to elastomeric housings or casings, e.g. of mobile phones; or to elastomeric touch buttons, touch pads or keyboards. These products and components can be seen as different individual inventions.
The invention is described in greater detail below with reference to embodiments that are illustrated in the figures. The figures show:
Printing directly onto an elastomer body encounters problems due the anisotropy of the elastomer material and the resulting non-uniform on non-homogenous surface properties. The printing becomes even more difficult and prone to failures if the surface onto which the structure should be printed is not planar.
In a second step (
In a third step (
In a fourth step (
Alternatively, the entire foil 2 may be laminated to a sheet of elastomer substrate (not shown). The elastomer body may then be formed either during or after the lamination step. Individual elastomeric components may be obtained after cutting.
| Number | Date | Country | Kind |
|---|---|---|---|
| 00836/20 | Jul 2020 | CH | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CH2021/050013 | 6/30/2021 | WO |
