DE2647108A1 - Continuous metallising of glass fibre - using four bath system for pretreatment, silvering and copper coating with intermediate washes - Google Patents

Abstract

Non-metallic fibres are given an outer metallic coating by (1) passing the fibres through a first treatment bath for degreasing and cleaning (pref. with chrome-sulphuric acid) (2) sensitised in a second bath pref. contg. ZnCl2 soln. (3) premetallised in a third bath, pref. with silver and made conductive and (4) plating in a fourth bath, pref with Cu. Used for the continuous coating of fibres esp. of optical glass with a metallic conductive coating. Process is inexpensive.

Description

Process and device for continuous metallization

of non-metallic continuous fibers The invention relates to a method for the continuous metallization of non-metallic continuous fibers and a Device for carrying out the method.

Electrically non-conductive continuous fibers made from non-metallic materials such as plastic, glass or ceramics are increasingly being used for the most diverse Areas of application used. During their further processing or in later use they are exposed to the risk of mechanical damage or corrosion. In doing so, they often lose their advantageous properties. This danger exists especially when using glass fibers as light guides. In this use an electrically conductive coating offers further advantages. For example, Hr could for fault location or for German transmission of electrical signals. Known is a metallized glass fiber with a metal-containing coating in which the coating is made of metal and an intermediate layer consists of an oxide of this metal and the total thickness of the coating does not exceed one micron. The procedure for Manufacture of such glass fibers consists in applying a solution to the glass fibers a metal salt or a metal complex is applied, this compound transferred in situ to metal oxide at the same time or immediately after application to form a coating of metal oxide on the fibers and then at least the surface of the metal oxide coating is reduced to the corresponding metal (DT-PS 18 03 710). This known method can be used for the production Do not use metallized light guides. Once there is the coating obtained in this way too thin to offer mechanical protection. Furthermore, German is preserved in this way Metal layer permeable to moisture, so it can only delay corrosion, but not prevent it. In addition, you would benefit from using this procedure for light guides, their optical properties deteriorate significantly. That is in particular on the relatively high temperatures that occur in the individual process steps needed to be traced back.

The invention is based on the object of a method and a device to find the implementation of the method, with which inexpensively and continuously a closed metal layer several microns thick is applied to glass fibers without deteriorating their optical properties.

According to the invention, this object is achieved by a method according to the characteristics of claims 1 to 10 and by a device according to the characterizing part of the claims 11 to 13 solved.

The advantages achieved with the invention are in particular: dz it is possible through the use of a prietalization, almost as desired thick layers of metal on the relatively problem reading galvanic To find ways. A system operating according to the method described of about lo m in length is able to produce copper tubes up to about 20 microns at a throughput speed of about 20 to 80 cm per minute. By lengthening the system and / or by deflecting and repeatedly passing the fibers through the plating bath arbitrarily increased production speeds possible. The metal layers thus obtained are cohesive, shiny and not permeable to moisture. Another A substantial increase in the production speed is possible in that a almost any number of fibers passed through the individual baths at the same time can be.

An embodiment of the invention is shown in the drawing and is described in more detail below. It shows: Fig. 1 a complete device, FIG. 2 shows a flow-through container, FIG. 3 shows the winding device.

In Fig. 1 is an apparatus for continuous metallization of continuous fibers, on the basis of which the process is also clearly illustrated can, drawn schematically. Are on a base frame 1, in the direction of travel Seen fibers 2, the individual parts described below are arranged one behind the other: An unwinding device 3 with replaceable supply reels 4 for the untreated Fibers 2, a centering triohter 5, which for example consist of plastic or glass can and the fibers 2 regardless of the filling level of the supply reel 4 without danger the damage leads to the central position for the following baths, and a first tubular container 6 for the degreasing and cleaning bath. He is through the Filler neck 7 with one for degreasing and cleaning the respective fiber material suitable liquid kept filled, in the case of the metallization described later from glass threads has saturated chromic acid, a mixture of concentrated Sulfuric acid H2804 and Potassium dichromate K2Cr2O7, as advantageous proven. Seen in the running direction of the fibers 2 behind the container 6 for the cleaning bath is another tubular container 8 for rinsing the cleaned fibers 2 arranged, the over the filler neck 9 with a continuous detergent, in Example is kept filled with distilled water. This is followed by a tubular one Container lo with filler neck 11 for the sensitizing bath in which the surfaces the fibers are prepared for the following treatment step. In case of For this purpose, the metallization of glass fibers is a hydrochloric acid tin-11 chloride solution SnCl2 + HCl proved to be advantageous. This is again followed by a tubular container 12 for the second rinse, which is filled with a detergent via its filler neck 13, in the example Deionat, is kept filled. This is followed by a tubular container 14 clip with trap 15, in which a pre-metallization of the fibers 2 after Reduction process takes place so that these become electrically conductive. In case of Metallization of glass fibers becomes a reduction silver plating solution through the filler neck 15 filled with an ammoniacal silver salt solution, an alkaline buffer, for example alkaline Seignette salt solution, and a reducing solution, for example Formalin, hydrazine or phosphorous acid. After another rinsing container 18 with a filler neck 19 for the deionized water is followed by a further rohrtbrmigor, the Container 14 is the same as container 20 with filler neck 21 and a further rinsing container 24 with filler neck 25. This container 20 is used as a reserve pre-plating bath uses what has proven to be very beneficial for continuous operation, to correct any problems with the silver plating in the container 14. The effectiveness this bath can be extended, especially in the case of pre-silvering of glass fibers if the sludge that settles during the treatment is removed from time to time For this purpose, a later described in detail and shown in Fig. 2 is used piston-shaped cleaning device in containers 14 and 20 for pre-metallization and reserve pre-metallization, which are connected through the connecting pieces 16 and 17 or 22 and 23 running threads can be moved and the deposited Pushes mud through the ends of containers 14 and 20, respectively.

After the fourth rinsing bath 24 following the pre-metallization the now pre-metallized fibers 2 rubbing against a polished metal Electrode 26 led along which the fibers 2 for the galvanic pre-metallization supplies the necessary current cathodically. Then the fibers 2 are in an elongated, several meters long, open-topped, bowl-shaped container 27 with the metal wire mesh existing anode 28.

This is where the galvanic metallization takes place. In the case of metallination of glass fibers, copper plating has al been shown to be advantageous. In this case the galvanic bath consists of 10 to 100 g / l copper, advantageously in the form of copper sulfate CuSO4.10 to 100 g / l sulfuric acid H2S04 and 0.01 to 1 g / l sodium chloride NaCl, remainder distilled water. Its temperature should be between 25 and 300 C. Farther has the addition of a brightener, for example 0.1 to 25 g / 1 thiourea, Sulphonic acid, 1,4 butynediol, thiophenol or a cellulose compound are advantageous shown.

The anode 28 then consists of copper wire mesh. In the case of already Metallization of glass fibers, which has been mentioned several times, has been shown, since the galvanic Metallization to avoid damage to the pre-metallization, here silver plating, useful in two merging areas 29 and 3o with different current intensities takes place In the first area 29, copper plating takes place with a current intensity from 1 to 50 mA for each fiber for which the current is supplied through electrode 26 will.

In the second area 30, in which there is damage to the target is no longer to be expected, the final copper plating takes place with an amperage of 150 to 500 mA per paser. This stream is over the still to be described winding device 33, the take-up reel 35 made conductive by conductive coatings 34 and via the end-copper-plated fiber 2 supplied.

In Fig. 2 is the bath for the taking of the reduction silver plating (Pre-metallization) provided tubular container 14 enlarged and schematic shown. He is through the already mentioned filler neck 15 with the for Pre-metallization provided liquid kept filled. In the case of metal tiers A reduction silver plating is carried out here on glass fibers, in which mud settles in the laure of time. He is through a cleaning facility that consists of a piston-like tube piece 37 movable by plastic threads 36, pushed out of the end 38 of the container 14. The plastic threads 36 can over Deflection rollers 39 are guided and moved by a drive roller 40. They run away in the example through the guide stubs 16 and 17 arranged on the container 14 Piston-like piece 37 can also be made of a magnetic material and then moved by a magnet disposed outside of the container 14. The cleaning devices described enable the duration of the effectiveness of the bath can be extended as required. The container 20 for the continuous light Operation advantageous reserve pre-metallization is designed in the same way.

In Fig. 3 is the winding device 33 for the metallized threads 2 enlarged and shown schematically. The metallic axle 41 carries an exchangeable one Take-up reel 35 and is driven by a winding motor 42.Dio feed of the current for the second area 30 of the galvanic bath 27 takes place via the Spring 43, over the metallic axis 41 and over the coil body 35 applied Strip 34 of electrically conductive material, for example Leitailber, to the wound, metallized fiber only hinted at in the drawing further processing of the fibers 2, it has been shown to be advantageous if by a guide, not shown, for the fibers 2 for correct, layer-by-layer winding the fibers 2 is taken care of.

It can be seen that the base frame 1 is not shown separately Drip tray for the from the individual containers 6, 8, 10, 12, 14, 18, 20, 24, 27 and 31 liquids escaping through the inlet and outlet openings for the fibers 2 and those discharged from the containers 14 and 20 by the cleaning device 37 Mud and a drain for it. For those from the electroplating container 27 A separate collecting tray is expediently provided for escaping liquid.

L e r s e i t e

Claims (13)

Claims: 1. Process for continuous metallization of non-metallic continuous fibers that the fibers (2) in a continuous passage in a first passage bath (6) degreased and cleaned, sensitized in a second continuous bath (io), in one third pass-through bath (14) pre-metallized and made conductive, and in a fourth Continuous bath (27) are galvanically metallized. 2. The method according to claim 1, d a d u r o h g e k e n n -z e i o h n e t that the fibers (2) after each of the four continuous baths (6, lo, 14, 27) in between These conveyor belts (6, 10, 14, 27) arranged further conveyor belts (8, 12, 18, 24, 31) can be rinsed in water and / or deionized water. 3. The method according to claim 1, d a d u r c h g e k n n -z e i c h n e t that the fibers (2) in the first continuous bath (6) with saturated chromosulfuric acid degreased and cleaned. 4. The method according to claim 1, d a d u r o h g e k e n nz e i c h n e t that the fibers (2) in the second pass-through bath f (lo) with a hydrochloric tin II-chloride solution must be sensitized. 5. The method according to claim 1, d a d u r o h g e k o n n -z e i c h n e t that the fibers (2) in the third continuous bath (14) after the reduction process silver-plated and made conductive. 6. The method of claim 1, d a d u r o h g e k e n q -z e i c h n e t that the fibers (2) in the fourth continuous bath (27) in a sulfuric acid copper solution be galvanically copper-plated. 7. The method according to claims 1 to 5, d a d u r o h g e -k e n It should be noted that the fibers (2) in the fourth pass-through bath (27) merge into one another in two Transitioning areas (29 and 30) with different currents galvanically be metallized. 8. Verrahren according to claims 1 to 7, d a d u r o h g e -k e n It should be noted that the fibers (2) in the first area (29) of the fourth continuous bath (27) pre-coppered with a current of 1 to 50 mA and in the second area (30) can be copper-plated with a current of 150 to 500 mA. 9. The method according to claims 1 to 8, d a d u r c h g e -k e n It is not indicated that the galvanization for the first area (29) of the fourth pass-through bath (27) over a polished metal sheet (26) on which the silver-plated Fibers (2) are dragged past and that, seen in the direction of passage, is arranged in front of the fourth continuous bath (27), is supplied. lo. Process according to Claims 1 to 9, d a d u r o h g e -k e It is noted that the electroplating current for the second area (30) of the fourth thermosetting bath (27) over conductive coatings (34) from behind the last rinsing bath (31) arranged take-up reels (35) and their metallic axes is supplied. 11. Device for performing the method according to the claims 1 to lo, d a d u r c h g e k e n n n z e i e h e t that on a round frame (1) in the running direction of the fibers (2) are arranged one behind the other: an unwinding device (3) for the untreated fibers (2) with exchangeable supply spools (4) Tubular container (6) to be filled with saturated chromosulfuric acid for a Cleaning and degreasing bath, a tubular, with running water to be fed Container (8) for a first rinsing bath, a tubular one, with hydrochloric acid Tin-II-chloride solution container (lo) to be filled for a sensitization bath, a tubular container (12) for a to be fed with deionized water flowing through it second rinsing bath, a tubular container to be filled with reducing silver solution (14) for a silver plating bath, a tubular one that can be fed with deionized water flowing through it Container (18) for a third rinsing bath, a tubular one, with reduction silver plating solution To be filled container (20) for a reserve silver plating bath, a tubular, with continuous deionized water to be fed container (24) for a fourth rinsing bath, one the silver-plated fibers (2) cathodically contacting electrode (26), one at the top open, elongated, with an electrolyte suitable for galvanic copper plating to be filled shell (27) with an anode (28) made of copper wire mesh tubular container (31) to be fed with continuous deionized water for a fifth Rinsing bath, and a winding device (33) with a guide for the metallized Fibers (2). 12. The apparatus of claim 11, d a d u r o h g e k e n n -z e i c h n e t that in the containers (14 and 20) for the silver plating baths each consisting of a piston-like tube piece (37) which can be moved on plastic threads (36) Cleaning device is attached. 13. The apparatus of claim 11, d a d u r c h g e k e n n -z e i without the fact that the winding device (33) take-up reels (35) for the metallized Fibers (2) contains, by applied strips (34) of teitsilber as a tent cathodic contact device for the copper plating of the metallized fibers (2) is designed.