DE102007030924A1 - Plastic molded metallic strip conductor manufacturing method for e.g. battery sensor of vehicle, involves producing conductor, applying flame-pyrolytic coating of amorphous silicate layer on conductor, and molding conductor with plastic - Google Patents

Abstract

The method involves producing a strip conductor, cleaning a conductor surface with acid, alcohol and/or detergent, and applying a flame-pyrolytic coating of amorphous silicate layer on the conductor. The conductor cooled to a room temperature is inserted into an injection molding tool, and is molded with plastic. The conductor is made to contact a flame's oxidizing region, in which a siliceous substance e.g. organosilicon compound, silane and silicon hydride, is fed in the coating step. A halogenated substance, an organometallic compound or a metal hydride is fed to the siliceous substance.

Description

The The present invention relates to a process for the preparation of plastic-coated conductor tracks with one possible low leak rate.

at the manufacture of electrical equipment or components are usually used conductor tracks, the mechanical Fixing and electrical connection of electronic components serve. Under conductor is therefore according to the invention both a circuit board and a current-carrying layer with appropriate layer thickness and width understood. often These interconnects are integrated in housing or should be mechanically protected due to harsh environmental conditions. The printed conductors are therefore back-molded or overmoulded with plastic.

ever After component, it is necessary that the over-molded conductor track is gas-tight. Due to the different thermal expansion coefficients As a rule, compounds of metals and plastics are not particularly gas-tight, allowing leakage rates of up to 7 ml / min measured become. This is when used in the presence of corrosive gases of great disadvantage. For example, at Battery sensors leak sulfuric acid vapor and damage the vehicle or the sensor.

to Improving the connection of two components are quite a few known by methods that cover the surface of one or all Change components. However, this is for depending on the material to decide which case Process for which substances are suitable. So are plasma flame known for surface treatment, which is the surface cleanse and make more reactive.

From the DE 10 2006 045 951 A1 is a method known in which plastic surfaces are activated with a flame, wherein the flame halogenated and / or siliceous substances are added. The disclosed teaching relates to improved wetting or adhesion of intended for coating / bonding of the plastics materials such as paints. It is also known to treat glass or ceramic surfaces with such a flame to better apply powder coatings.

The The present invention has for its object to provide a method for Production of a plastic-coated metal conductor track as well specify such a track, which is as gas-tight as possible Compound leads the substances.

The The object is achieved by a method comprising the Steps: a) Finishing the trace, b) flame pyrolytic deposition a silicate layer on the conductor track, c) encapsulation of the conductor track with plastic. The conductor track produced in a known way comprises the base material of fiber-reinforced resin and the pressed-in Cu conductor together with Cu or Au contacts for contacting the conductor track or according to the invention also as a conductor track understood punched body made of Cu or Cu alloy, where no electronic components are attached. Before the encapsulation the conductor in an injection mold is now inventively with great advantage a flame pyrolytic deposition of amorphous silicate on the surface of the conductor track, or their contacts. This deposition leads to a significant increase in the track surface, a higher surface energy, a higher one Polarity of the track surface and allowed by the introduced SiOH groups further chemical reactions, so that a more gas-tight bond between the metal of the conductor track and the plastic with great advantage possible is. In general, the Applicant has found that Metals with a flame-pyrolytically deposited silicate layer gas-tight with plastics.

In Embodiment of the method is provided that between step b) and step c) a step b1) takes place, in which the workpiece is cooled to room temperature, preferably in one dry environment, and then into an injection mold is inserted, preferably automatically. The cooled Workpiece is easier to handle and safer, at the same time there is enough time to form a solid connection of metal and deposited silicate. Is the Dry environment, saturates the hydrophilic silicate layer not with water, their reactivity is maintained. on the other hand It may also be desired to use the surface Water molecules to saturate with this water or in this watery environment reactions between plastic and workpiece surface to enable.

Becomes which cleans the surface of the track, preferably with an acid, an alcohol or a detergent before the flame pyrolytic coating takes place, so the connection between Silicate and metal of the track homogeneous, since no uninvited Pollution sites are present.

In an embodiment of the method provides that in step b) the conductor is contacted with the oxidizing region of a flame, in which a silicon-containing substance is metered, which oxidized in the flame and as an amorphous silicate in a thin, adherent layer on the metal the conductor separates. The flame is there preferably a gas flame of an oxidizable hydrocarbon such as butane, propane or hydrogen and an oxidizing agent such as oxygen or air. As the silicon-containing substance, hexamethyldisiloxane is preferably used. Details of this step and in particular the dosed into the flame substances are DE 10 2006 045 951 A1 refer to.

As a general rule can the silicon-containing substances according to the invention organosilicon Compounds, silanes or silicon hydrides.

Becomes simultaneously with the silicon-containing substance a halogen-containing Substance metered and / or an organometallic compound or a metal hydride, so the adhesion and the gas tightness can still be improved.

claimed will continue a plastic-coated conductor having a Silicate layer between the metal of the track and the plastic with a gas tightness of less than 2 ml / min and in particular a battery sensor housing.

The Invention is in a preferred embodiment below With reference to a drawing described by way of example, where further advantageous details to refer to the figures of the drawing are.

functionally the same parts are provided with the same reference numerals.

The Figures of the drawing show in detail:

1 a perspective view of the body of a battery sensor and

2 , a perspective view with molded body.

1 shows a component after the process step b). Shown is a base body for a battery sensor with a pole terminal 1 connected to a pole of a battery by means of a screw 6 is attached non-positively. From the pole clamp 1 An arm protrudes away, a shunt at its free end 2 wearing. At the shunt 2 are three sensor pins 3 secured by laser welding. These sensor pins 3 make the electrical contact to a sensor, not shown, and are about 11 mm long. The arm with shunt 2 is by brazing on the pole terminal 1 attached. An indicated coating 4 surrounds the entire arm and shunt 2 in the sketched areas. This in 1 shown component consists of a Cu alloy, namely a bronze CuZn37Pb2.

2 shows the state of the component after process step c). The component is now with the previously 4 Marked points of Sillikatschicht have been encapsulated with plastic, so that there was an open-topped housing. This housing accommodates the sensor and electronics that pass over the sensor pins 3 and the connector pins the voltage drop on connected to a battery cable shunt 2 measure and evaluate the state of charge at the pole terminal 1 fixed battery can determine. To complete the housing is provided with a lid and this inextricably connected by plastic laser welding to the housing. This housing is gas-tight. The housing was manufactured according to the following embodiment.

The to be sprayed bronze assemblies are for 12 min in 6 cm distance from the flame exit from a hand burner through passed a silane flame. After cooling to room temperature The workpieces are in a commercial injection mold introduced with a cavity and overmoulded with PBT GF-30. The finished component is used for cooling and shrinking stored. The test for tightness at 700 mbar negative pressure results a leak rate of 0.05 to 1.6 ml / min, even after passing through of eight temperature cycles from -40 ° C to 110 ° C does not increase.

1

Polklemme

2

shunt

3

sensor pin

4

flammenpyrolytische layer

5

casing

6

screw

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006045951 A1 [0005, 0010]

Claims (7)

Process for producing plastic-coated Printed circuit traces, comprising the steps: a) manufacturing the printed conductor, b) flame pyrolytic deposition of a silicate layer on the Trace, c) overmold the trace with plastic. The method of claim 1, wherein between step b) and step c), a step b1) takes place, in which the Workpiece is cooled to room temperature, preferably in a dry environment, and then in an injection mold is inserted, preferably automatically. A method according to claim 1 or 2, in which before step b) a step a1) takes place, in which the surface the conductor is cleaned, preferably with an acid, an alcohol and / or detergents. A method according to claim 1, 2 or 3, wherein in step b) the conductor track with the oxidizing region a flame is contacted, in which a silicon-containing substance is metered in, which oxidizes in the flame and as amorphous silicate in a thin, adherent layer on the Metal of the conductor path separates. Method according to one of the previous Claims in which the silicon-containing substance is an organosilicon Compound, a silane or a silicon hydride is. Method according to one of the previous Claims, wherein at the same time to the silicon-containing substance a halogen-containing substance is metered in and / or an organometallic Compound or a metal hydride. Plastic-coated conductor track having a silicate layer between the metal of the track and the plastic, in particular a battery sensor housing.