DE2127650B2 - Electrical resistor contact formation - using fluxing paste of org binder and silver - Google Patents

Abstract

Carbon varnish coated filament microresistor has an electrical contact formed by applying to the varnish a fuxing paste of an org binder based on glyptal resins and finely dispersed Ag. The paste is fired at a temp causing no destruction of the carbon varnish coating, a flux is applied to the paste, and the fluxed portions are tinned.

Description

21 27 βδυ

The invention is based on a Explain the execution example in more detail:

On a continuously drawn glass thread with an applied paint soot resistance layer on the Base of the glyptal resins, which act as the carrier of the micro-resistance is used, conductive paste is applied to the contact points in a belt, which consists of a organic binder based on glyptal resins and finely dispersed silver in a weight ratio of 1:24 is composed.

The conductive paste must meet two main requirements:

1. It should have a good bond with the carbon black resistive layer have what is achieved by the affinity between paste and resistance layer will.

2. It should be capable of tinning, which is ensured by the flow properties of the glyptal resins.

The following mixture can be used as a paste:

Finely dispersed silver 100 parts by weight

Glyptal resin 10 parts by weight

Dibutyl phthalate 16 parts by weight

Solvent: xylene and
Turpentine oil in proportion
0.4 al per Ig finely dispersed
Silver

After applying the conductive paste, the belts are kept at a temperature of 280 Baked in up to 300 ° C within 30 to 60 s.

After this, alcohol-rosin or salicyl-glycerine flux should be applied to the paste belts and the areas treated with flux within 3 to 5 s with lead-zinc solder using of low temperature additives, e.g. B. Cadmium

ίο to be tinned at a temperature of 140 to 180 ^{= C.}

The baking temperature of the paste and the tinning temperature must be considerably lower than the temperature of the structural change of the resistive layer, which is the necessary condition for the Preservation of the constant resistance value of the resistance layer is.

After tinning, the glass thread provided with paste belts is cut in sections in the middle of the Cut off the belt, thereby gaining the individual micro-resistors with tinned contacts. The advantage of the method according to the invention is that it allows tin-plated contacts of the micro-resistors manufacture, which ensure their assembly by direct soldering in a circuit, whereby the inventive method for resistors with tinned contacts is fully automated can be.

Claims (3)

£ I df DOU 1 2 D ... only by gluing with the conductive mass Patent claims: be installed, as this cannot be tinned, 1. Method for attaching metallic cones so that these contacts are not in a circuit either clocks can be soldered onto a resistance layer made of carbon. fabric and a synthetic resin, which is based on a mineral 5 resistors with glass threads as a carrier body, however Kschen supports are applied, which are initially without a carbon-synthetic resin resistance layer on the hardened resistance layer on the also known elsewhere (DT-PS 9 73 900, DT-AS to be contacted "share a paste of silver 11 57 302). and synthetic resin applied and then with Next a curable conductive varnish with almost Temperatures of approximately 300 ^c C baked-in io metallic conductivity is described (DT-PS is described, with synthetic resins of the same type 5 94 402), with which resistance layers are used in contact, and then the metal on which a contact is to grind.
Iischen contacts at a temperature of high In addition, it is known (DT-PS 8 21 060), a At least 180 ⁰ C applied to the cured paste metallic Kor.tiktschicht on a carbon layer, characterized in that 15 resistance to burn and at the contact points as a mineral carrier a glass thread and as special prefabricated contact pieces such as caps, synthetic resin, the soot resistance layer and the clamps or Pressing on solder lugs.
Paste a resin from the group of glyptal resins Conductive varnishes on a synthetic resin basis have been are used and the metallic contacts are often described for contacting purposes, and after the application of flux on the out «for the contact points of metal deposits hardened paste by tin-plating melted electrical capacitors (DT-PS 9 69 523), as will. electrically conductive bridges between elec- 2. The method according to claim 1, characterized in that the paste on the continuous bodies such as windows and windshields (DT-AS drawn, coated with the soot resistance layer 25 10 28 183), preferably A silver lacquer-covered glass thread is used in sections in a ring shape, mixing ratio 43: 57, is applied and, after tinning with and for resistors and capacitors (DT-AS radial cuts through the center of the rings 10 78 656), the contact connections of which are preferably individual glass thread resistances obtained will. made of silver-plated copper powder and a hardenable one 3. The method according to claim 1 or 2, characterized in 3 ° resin based on phenolic resin in a weight ratio of 1: 1 characterized in that the paste is made from glyptal resin and. finely dispersed silver in a weight ratio of Manufactured from such stoving pastes with silver 1: 24 contains. Contact layers are also for with lead wires Electrodes to be soldered on ceramic, mainly The invention relates to a method for applying metallic contacts consisting of at least one manganate material to a resist (US Pat 512) known,
dit is applied to a mineral carrier. Finally, a glass filament resistor is known in which first on the hardened resistance (DT-PS 4 72 513), in which the over the entire layer at the points to be contacted a paste 4 ° glass thread length reaching thin metal coating high made of silver and synthetic resin is applied and then resistance with metal caps the two ends ßend at temperatures of approximately 300 ^: C is connected by the fact that the metal-coated is burned, each time synthetic resins of the same type glass thread are used in the metal inserted into the caps, and then the metallic low melting point such as tin is melted, contacts at a temperature of at most 180 ³ C 45, so that here, too, soldering into a circuit is not applied to the hardened paste. is immediately possible. A method of this type is known (US-PS The invention is based on the object that 27 81 277), according to which asbestos is used as a carrier, to be designed as a method mentioned at the outset so that with Synthetic resin for the resistance layer liquid silicones and micro-resistors with contacts and as the synthetic resin of the paste, silicone resin can be used, which can be directly incorporated into a circuit and one can be soldered to form metallic contacts. a mixture of epoxy resin and silver to create the object is achieved according to the invention dadurc'i, an adhesive material on the hardened paste that as a mineral carrier and a glass thread applies and aushr.rtet, after which the asbestos carrier synthetic resin, the soot resistance layer and the paste a resin from the group of glyptal resins is used when cut into the desired resistance elements will. and the metallic contacts after The silver contacts thus obtained are, however, the application of flux to the hardened paste cannot be soldered directly into a circuit. be melted by tinning. There is also a manufacturing method for electrical In an embodiment of the invention, as in the case Contacts of glass thread micro-resistors known 60 of the asbestos carrier according to the above-mentioned in the article "Some properties of conductive glues were known processes per se, the paste on the and their effect on the stability of the contact continuously drawn, with the soot resistance" in " Elektronraja technika «, No. 8, layer-covered glass thread applied in sections in Ring Edition 2 (23), Central Research Institute for Elek- form, and after tinning tronik, Moscow, 1971), according to which the contacts 65 with radial cuts the middle of the rings obtained individual glass filament resistances from an electrically conductive mass on the metal coating,
of the micro-resistor: however, the paste preferably contains glyptal resin and micro-resistors with such contacts can be fineJispciM ^ silver in a ratio of 1:24.