Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C45/14311—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles using means for bonding the coating to the articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C2045/1486—Details, accessories and auxiliary operations
  • B29C2045/14868—Pretreatment of the insert, e.g. etching, cleaning
  • B29C2045/14885—Pretreatment of the insert, e.g. etching, cleaning by plasma treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
  • B29C37/0078—Measures or configurations for obtaining anchoring effects in the contact areas between layers

Definitions

• the invention relates to a method for producing a component coated with a thermoplastic layer.
• thermoplastic layer Components that are coated with a thermoplastic layer, you will find numerous in industrial production.
• the known injection molding can be used, in which plastic molded parts are generally made from molding materials.
• powdered or granular injection molding materials are plasticized by an injection molding machine and injected at high pressure into the shaping cavity of an injection mold.
• Thermoplast melt impinges on metal parts whose temperature is well below the melting point of the thermoplastic. Immediately a thin layer of solidified material forms in the melt at the interface with the metal. H. A detonated thermoplastic material which does not adhere to the metal. Since in addition the further melt in the injection molding tool solidifies while reducing its volume during the further cooling process, this results in at least partial detachment of the thermoplastic layer from the metal surface. Although this effect ensures on the one hand a good mold release of thermoplastics from metallic injection molds, but on the other hand it makes it difficult to liquid-or gas-tight encapsulation of metallic inserts such as the pins in plugs and controllers.
• thermosetting epoxy molding compounds In comparison with an adhesive bond or an encapsulation with thermosetting epoxy molding compounds, there is no appreciable adhesion between the thermoplastic and the metal insert during extrusion coating with thermoplastics. The only slight adhesion does not allow transmission of tensile or shear stress. In addition, thin gaps between the overmolded metal parts and the thermoplastic arise.
• thermoplastic layer Another way to solve the problem of poor adhesion is to provide a primer layer between the component and the outer thermoplastic layer.
• a method is described in the unpublished DE-103 61 096.0, after which a primer layer is applied to metallic components in a first step.
• the encapsulation of the thermoplastic layer is carried out on the now coated with the adhesive layer component, wherein the adhesive layer is welded to the thermoplastic layer such that between the metallic component and the thermoplastic layer no gaps occur and a frictional connection between the thermoplastic layer and the adhesion promoter layer and thus ultimately also between the thermoplastic layer and the metallic component is present.
• the interface temperature between the thermoplastic melt and the bonding agent layer occurring during the encapsulation process must be sufficiently high for the welding process. moreover both layers to be joined must be compatible with each other, ie in principle be welded together.
• the softening temperature of the primer layer should be sufficiently low to ensure a good weld with the thermoplastic encapsulation, on the other hand sufficiently high enough to have a good temperature and media resistance.
• the primer layer must be elastic and its thermal expansion coefficient and thickness must be in definite relation to the corresponding values of the metal and thermoplastic layers.
• the primer layer could be made volume-compressible.
• US Pat. No. 6,620,517 B2 discloses a layer composite on a metallic component, wherein a rubber, an adhesion and a thermoplastic layer are applied one after the other on the component for its production. It is provided, after the application of the rubber layer to vulcanize these and optionally perform a plasma treatment on the surface of the vulcanized rubber layer.
• plasma treatments primarily with delacid plasmas, are known for surface cleaning of the layer to be treated, wherein the molecules of the treated layer itself are not changed in structure, but typically impurities are removed from the layer.
• the method for producing a component coated with a thermoplastic layer according to claim 1 has the advantage that the adhesion of the thermoplastic layer to the component is substantially increased or only made possible. In fact, experimental studies have shown that even with material combinations that are otherwise incompatible, good adhesion could be achieved with the method according to the invention. This results in a wider choice of usable materials. It is advantageous that the method requires no additional, large technical effort, so that it can be carried out in an economical manner. The high quality of the finished components also contributes to the economic efficiency of the method.
• the components coated with a thermoplastic layer are gas-tight and liquid-tight after encapsulation, so that subsequent processing to seal the components is not necessary.
• the method is not only suitable for metallic components, but also for components made of thermosetting materials.
• Figure 1 is a produced according to the invention, coated
• FIG. 2 shows another coated component produced according to the invention with an intermediate layer between the component and the thermoplastic layer, wherein the intermediate layer is provided with a thin adhesive layer.
• FIG. 1 shows a component produced by the method. The following steps are provided for the production of a component coated with a thermoplastic layer:
• step a) providing the component (10), b) applying an intermediate layer (20) of a plastic on at least one part of the component (10), c) performing a plasma treatment of the intermediate layer (20) with a plasma gas, wherein the molecules or the structure the molecules of the intermediate layer (20) are modified at least on the surface of the intermediate layer (20), and d) injection molding of the thermoplastic layer (30) in such a way that the thermoplastic layer (30) and the component (10) provided with the intermediate layer (20) are frictionally engaged stick to each other.
• the component to be coated (10) is provided.
• the component is made of a metallic material, but may also consist of a thermosetting material.
• an intermediate layer (20) made of a plastic is applied to at least one part of the component (10).
• the plastic may be a thermoplastic such as polyamide, a thermoplastic elastomer (TPE) such as polyether block amide (PEBA), an elastomer such as vulcanized rubber or a cross-linked silicone.
• TPE thermoplastic elastomers
• PEBA polyether block amide
• elastomer such as vulcanized rubber or a cross-linked silicone.
• TPE thermoplastic elastomers
• fluororubber or fluorosilicone are also interesting because they are resistant to media and high temperatures.
• the intermediate layer (20) ideally has a thickness of 10 ⁇ m up to a few 100 ⁇ m, a maximum of about 1 mm. This large selection of materials for the intermediate layer (20) and thus to the substance combination intermediate layer (20) / thermoplastic layer (30) is only made possible by the subsequent plasma treatment of the intermediate layer (20).
• the molecules or the structure of the molecules of the intermediate layer (20) are modified at least on the surface of the intermediate layer (20).
• the intermediate layer (20) can be treated with a low pressure or atmospheric pressure plasma.
• the process pressure in the former case is advantageously about 0.1 to 0.5 mbar, in particular 0.3 mbar. If, on the other hand, one works with an atmospheric pressure plasma, it is possible to dispense with a vacuum chamber and to move components directly on an injection molding machine, for example with a robot through a plasma lance.
• a plasma gas for the plasma treatment is a gas mixture containing, for example, silane, or purer Used oxygen. Next can be added as a protective gas argon.
• the modification of the plastic surface can be done in different ways depending on the composition of the plasma gas.
• a surface layer may be formed from constituents of the plasma gas.
• fragments of the plasma gas for example oxygen (oxidation)
• oxygen oxygen
• Intermediate layer (20) shows an improved frictional connection in the subsequent overmolding with a thermoplastic material in step d).
• gas and liquid-tight components are obtained by this method.
• the plasma-treated intermediate layer (20) between the steps c) and d) with a thin, reactive adhesive layer (25) provided with a thickness of a few microns In the case of two-component adhesives, this is often possible already at room temperature the adhesive also meets the requirements for temperature and media resistance.
• Example 2 Interlayer (20): TPE-E layer, "Hytrel 5555 HS” with a thickness of 1.0 mm
• Plasma treatment O 2 plasma, 2 times 180 sec at 0.3 mbar tensile shear strength with plasma pretreatment: 15.9 MPa
• Plasma treatment O 2 plasma, 2 times 180 sec at 0.3 mbar tensile shear strength with plasma pretreatment: 4.1 MPa
• Example 6 Interlayer (20): polyamide 12-GF15, "Vestamid L-GF15" with a thickness of 1.0 mm
• Intermediate layer (20) Fluorosilicone layer, "Type 4-9060” from Dow Corning with a thickness of 1.0 mm
• Thermoplastic layer (30): Polyphenylene sulfide (PPS), "Ryton R4-200” Plasma treatment: O 2 plasma, 2 times 180 sec at 0.3 mbar tensile shear strength without adhesive: 0 MPa tensile shear strength with adhesive: 2.5 MPa

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Laminated Bodies (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (7)

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Citations (1)

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• 2005
  • 2005-07-06 DE DE102005031606A patent/DE102005031606A1/de not_active Ceased
• 2006
  • 2006-06-14 CN CN2006800246382A patent/CN101218082B/zh not_active Expired - Fee Related
  • 2006-06-14 WO PCT/EP2006/063185 patent/WO2007003490A1/de not_active Ceased
  • 2006-06-14 EP EP06777322A patent/EP1901906A1/de not_active Withdrawn
  • 2006-06-14 BR BRPI0612725-8A patent/BRPI0612725A2/pt not_active IP Right Cessation
  • 2006-06-14 US US11/922,053 patent/US20100065195A1/en not_active Abandoned
  • 2006-06-14 JP JP2008519893A patent/JP2009500200A/ja active Pending

Patent Citations (1)

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