DE1149142B - Continuous process for the production of a metal coating on glass threads - Google Patents

Description

The invention is directed to a continuous process for producing a metal coating Glass thread. It is known to coat single filaments with a metal layer in that they are individually passes through a metal melt, the metal layer is vapor-deposited onto the individual threads or the individual threads after a treatment with them chemically attacking bath fluids by electrolytic Deposition is provided with a metal coating.

These metal coatings should give the individual threads a higher tensile strength, but in particular a better one Maintain resistance to bending stresses. It is known that glass threads, in particular when combined to form a strand, are very sensitive to bending loads because the individual glass threads in this strand association grind each other.

In addition, such single threads provided with a metal coating are more resistant to Influence of moisture and can be produced in a wide variety of colors.

The method according to the invention is distinguished from the known methods in that on a running, endless, taut strand of individual glass thread first a concentrated ammoniacal Silver salt solution and then a concentrated aqueous solution of a reducing agent applied and the strand is washed with water after formation of the silver coating.

The creation of a firmly adhering, shiny mirror from a metal, such as silver, on glass surfaces by making the silver from a dilute silver salt solution applied to the glass surface reduced is already known per se.

The invention makes use of this basic teaching, but it must Tightened strands of individual glass threads to the extent that problems arise, as this Do not strands through successive baths with the silver salt solution and the solution of the reducing agent can be passed through. Rather, the reaction between these two solutions must be be carried out on the strand itself.

One makes use of the fact that between the individual glass threads from which the running, There is an endless, tightened strand, the smallest capillary spaces remain, into which the liquid penetrates. In these smallest spaces, which thus serve as a reaction vessel, takes place also the mixture between the silver salt solution and the reducing agent solution and the deposition of the metallic silver on the individual threads.

Continuous process for producing a metal coating on glass threads

Applicant:

Owens-Corning Fiberglas Corporation,
Toledo, Ohio (V. St. A.)

Representative: Dipl.-Ing. R. H. Bahr

and Dipl.-Phys. E. Betzier, patent attorneys,

Herne, Freiligrathstr. 19th

Claimed priority:
V. St. v. America of December 16, 1953 (No. 398 544)

Harry B. Whitehurst of Newark, Ohio (V. St. A.) has been named as the inventor

In order to be able to carry out the process continuously in this way, it does not concern the to use the usual dilute metal salt solutions for the known mirroring, but one has to with a concentrated silver salt solution and a likewise concentrated solution of the reducing agent work because this is the only way to ensure that the reaction between the silver salt solution and the reducing agent solution occurs on the current strand for a not too long time.

In contrast to the production of optical mirrors by silvering larger glass surfaces with It comes with the help of applied dilute silver salt solutions and reducing agent solutions Application of metal coatings on glass threads not to the utmost uniformity and gaplessness of the Coatings because they meet the requirements even with less uniformity To make threads more resistant to tension, bending and moisture.

Compared to the known method, the method according to the invention obviously has essential features Benefits on. The first advantage is to be seen in the fact that it is possible to use the individual threads to a sufficient extent to be provided with the metal coating in the association of the much more tensile strand. This differs the method according to the invention is fundamentally different from all other methods in which the

309 597/140

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zelfaden is the object to which the metal coating is applied directly.

Another advantage of the method according to the invention can be seen in the fact that the process is carried out continuously without the individual Threads are subject to increased stress, for example when passing through a molten bath or in the case of the electrolytic application of the metal coating after prior chemical attack subject to the threads.

Compared to a vapor deposition process, the process according to the invention not only has the advantage of continuous procedure, but in particular also has the advantage of a much simpler one Apparatus.

The washing of the strand after the formation of the silver coating serves to remove the effects during the implementation and any residues arising between the silver salt solution and the reducing agent solution to interrupt the reaction.

As the silver salt solution, one of 50 parts by weight of silver nitrate and 35 parts by weight of one is preferred 29% aqueous ammonia solution produced solution used, then used as a reducing Solution a saturated aqueous solution of hydrazine sulfate is used.

In order to accelerate the course of the reaction, the strand can be heated after the reaction solutions have been applied.

Should a strand coated with a size in connection with the method according to the invention Find use, then you will of course this strand before wetting with the solutions free from the size, which is expediently done by heating the strand to 485 to 650 ° C.

If the strand is pretreated with a solution in a manner known per se for silver plating, for example from 15 parts by weight of stannous chloride, 12 parts by weight of hydrochloric acid and 4500 parts by weight If there is water, it can also be used without first removing any possibly existing Sizing can be treated immediately by the method according to the invention.

The drawing shows an exemplary embodiment for tensioning pulley 14 and a variety of idling Rollers 15. It runs under the containers 16 and along, each of which is provided with a measuring tap 18 are.

The treatment solutions are filled into these containers; H. the container 16 contains a concentrated ammoniacal silver salt solution, while in the container 17 a concentrated aqueous solution a reducing agent is filled. These two solutions drop onto the strand 11, whereby on the way to the washing bath 19, the reaction between the two solutions on and within the Strand 11 takes place. In the washing bath 19, the strand runs over a roller 20 submerged there and becomes freed from the reaction residues.

After leaving the last roll 15, the strand, which is now provided with the metal coating, is opened the winder 13 with HMe of the thread guide 22 wound up to form a spool 21.

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Claims (3)

PATENT CLAIMS: 1. Continuous process for producing a metal coating on glass threads, characterized in that first a concentrated ammoniacal silver salt solution and then a concentrated aqueous solution of the reducing agent, applied to a running, endless, taut strand of individual glass threads and the strand after formation of the silver coating with Water is washed. 2. The method according to claim 1, characterized in that one of the silver salt solution 50 parts by weight of silver nitrate and 35 parts by weight of an aqueous 29% ammonia solution produced solution and as a reducing solution a saturated aqueous solution of hydrazine sulfate is used. 3. The method according to claim 1 or 2, characterized in that the strand after application the reaction solutions is heated. Documents considered: German Patent No. 833 997; German patent application G 7832 VIb / 32 a (a system with which the method 45 according to the invention was made known on November 13, 1952); can be carried out. Swiss Patent No. 262747; The one from, for example, 200 and more individual K.A. Hofmann and U.R. Hofmann, »Anor- Strand 11 consisting of glass threads is fed by a coil ganische Chemie «, 11th edition, 1945, p.532und533; 12 continuously processed and passed on his Woldemar K. Weyl, "Colored Glasses", Sheffield Ways to the take-up device 13 one after the other a 50 1951, p. 348 to 351. 1 sheet of drawings © 309 597/140 5.63