US3069289A - Protective backing for mirrors - Google Patents
Protective backing for mirrors Download PDFInfo
- Publication number
- US3069289A US3069289A US16151A US1615160A US3069289A US 3069289 A US3069289 A US 3069289A US 16151 A US16151 A US 16151A US 1615160 A US1615160 A US 1615160A US 3069289 A US3069289 A US 3069289A
- Authority
- US
- United States
- Prior art keywords
- copper
- iron
- suspension
- bentonite
- particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000001681 protective effect Effects 0.000 title description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 34
- 229910052742 iron Inorganic materials 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 16
- 239000000440 bentonite Substances 0.000 claims description 14
- 229910000278 bentonite Inorganic materials 0.000 claims description 14
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 12
- 229910000365 copper sulfate Inorganic materials 0.000 claims description 11
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 claims description 11
- 239000000725 suspension Substances 0.000 claims description 10
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 7
- 229910052709 silver Inorganic materials 0.000 claims description 7
- 239000004332 silver Substances 0.000 claims description 7
- 239000011253 protective coating Substances 0.000 claims description 6
- 239000007900 aqueous suspension Substances 0.000 claims description 5
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 claims 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 17
- 229910052802 copper Inorganic materials 0.000 description 17
- 239000010949 copper Substances 0.000 description 17
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 14
- 239000000243 solution Substances 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 239000002184 metal Substances 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002923 metal particle Substances 0.000 description 7
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 239000010410 layer Substances 0.000 description 6
- 239000007921 spray Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 4
- 238000005507 spraying Methods 0.000 description 4
- 239000012530 fluid Substances 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 238000006748 scratching Methods 0.000 description 2
- 230000002393 scratching effect Effects 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical compound CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/54—Contact plating, i.e. electroless electrochemical plating
Definitions
- the present invention relates to a novel method and composition for the plating of freshly silvered mirrors with a protective layer of copper, by chemical as distinguished from electroplating means.
- the process of the present invention in general relates to the employment of the known principle of the electroinotive series of elements wherein one metal will displace another which is lower in the electromotive series from solution.
- copper may be precipitated out from a solution of copper sulfate by commingling the copper sulfate solution with a suspension of finely divided particles of metal above it in the electromotive series such as iron, zinc, etc., and this expedient has been heretofore employed for the deposition of a coating of copper on a freshly silvered mirror for protection of the silver layer.
- the process comprises the employment of a solution of copper sulfate with added mineral acid and the joint spraying and commingling thereof with a suspension of finely divided metal particles onto the silvered mirror by, for example, passing a freshly silvered mirror forwardly on a conveyor in a horizontal or substantially horizontally disposed position while moving the sprays transversely of the path of the mirror and in a plane substantially parallel thereto.
- I prepare a first solution composed of three pounds of copper sulfate, 5.25 pounds (44 fluid ounces) of 66 B. concentrated sulfuric acid and from about 14 to about 17 gallons deionized water. I then prepare a dispersion composed of approximately two ounces of pulverized iron, all of which passes a ZOO-mesh sieve but all of which is retained on a BOO-mesh sieve, and eight ounces of bentonite (Volclay BC having a pH of from about 7.5 to about 8.5). These two liquid bodies may be separately placed in overhead tanks and flowed by gravity to spray nozzles employing 15 to 25 pounds of air pressure.
- the copper sulfate solution may be sprayed at the rate of sixteen fluid ounces per minute and the iron particlebentonite suspension at the rate of five to six fluid ounces per minute at a point of about eight to fourteen inches above rinsed, freshly silvered glass passing thereunder on a substantially horizontal support while the nozzles reciprocate perpendicularly to the motion of the glass and in a plane substantially parallel thereto.
- Multiple nozzle sets are preferably employed whereby one can deposit as thick a film of copper as desired.
- the commingled sprays fall upon the silvered surface as a light mud, the mud holding the reagent chemicals in contact and preventing run-off and thereby permitting full reaction of the chemicals.
- Successive applications may be made without intermediate rinse, and after passing under as many sprays as desired, the mirror is then rinsed with low-conductivity water, resulting in a copper-clad mirror free from blemishes at either the silver or copper deposits, which may then be used without further coating.
- the first solution prepared with from about 14 to 17 gallons of deionized Water may contain from about 1 to about 6 pounds of copper sulfate and from about 1 /2 to about 8 pounds of 66 B. sulfuric acid.
- the dispersion of iron powder and bentonite per gallon of water may contain the iron powder in the proportions of from about /2 to about 4 ounces and the hentonite from about 4 to about 10 ounces by Weight.
- Finely divided particles of iron suspended in an aqueous bentonite dispersion in the proportion of from about 4 to about 10 ounces by weight of bentonite and from about /2 to about 4 ounces by Weight of iron per gallon of water.
Landscapes
- Chemical & Material Sciences (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemically Coating (AREA)
Description
United States Patent 3,069,289 PROTECTIVE BACKING FOR MIRRORS William C. Bryant, Lombard, Ill., assignor to Turner Manufacturing Company, Chicago, 111., a corporation of Illinois N0 Drawing. Filed Mar. 21, 1960, Ser. No. 16,151 6 Claims. Cl. 117-71 This invention relates to improvements in the production of mirrors, and to the provision of a protective backing for mirrors.
More particularly, the present invention relates to a novel method and composition for the plating of freshly silvered mirrors with a protective layer of copper, by chemical as distinguished from electroplating means.
The process of the present invention in general relates to the employment of the known principle of the electroinotive series of elements wherein one metal will displace another which is lower in the electromotive series from solution. Thus, for example, copper may be precipitated out from a solution of copper sulfate by commingling the copper sulfate solution with a suspension of finely divided particles of metal above it in the electromotive series such as iron, zinc, etc., and this expedient has been heretofore employed for the deposition of a coating of copper on a freshly silvered mirror for protection of the silver layer.
It is a particular object of the present invention to provide a protective coating of metallic copper on a silvered i mirror in the general manner aforesaid, which is without blemish of either the silver or the copper layers successively deposited, which are resistant to aging and which require no further protective coating.
It is a further object of the present invention to provide a better process control and facilitate the nandling of the finely divided metal particles employed for displacing the copper from solution in a manner whereby the reaction may be tempered, and whereby the chemicals are permitted to react fully with attendant economy, and with prevention of abrading of the silver layer onto which the copper is deposited.
As heretofore indicated, the process comprises the employment of a solution of copper sulfate with added mineral acid and the joint spraying and commingling thereof with a suspension of finely divided metal particles onto the silvered mirror by, for example, passing a freshly silvered mirror forwardly on a conveyor in a horizontal or substantially horizontally disposed position while moving the sprays transversely of the path of the mirror and in a plane substantially parallel thereto.
This has generally required the use of a vessel equipped with a stirrer for keeping the metal particles agitated in a body of water substantially close to the point of spraying so that the metal particles will be dispered in as uniform manner as possible. Such procedure has also heretofore required the employment of extremely finely divided particles of metal, such as that which will all pass a 300- mesh screen and finer, primarily for the purpose of preventing scratching of the freshly silvered layer onto which copper is being deposited.
It is evident that such process requires care in the continuous agitation of the iron particles close to the work to maintain their suspension. Further, it has been found that the employment of such extremely finely divided particles of metal results in a too rapid action and often in nonuniform deposition of the desired copper layer.
In accordance with the present invention I am able to provide a better, simpler, and more uniform suspension of the metal particles; I am able to temper the reaction by being able to use relatively larger metal particles than heretofore thought feasible or desirable, such as 3,069,289 Patented Dec. 18, 1962 those passing a ZOO-mesh ,sieve but which all retained on a 300-mesh sieve, without scratching of the silver layer and with a better utilization of the chemicals.
These advantages are essentially accomplished by the addition of a small amount of bentonite to the metal powder suspension. Thus, I am able to prepare a good pre-suspension which is stable for the purposes herein contemplated, of metal particles and bentonite in water at a distance from the Work and to provide a consistently uniform spray thereof without necessity for employment of an agitator closely adjacent the point of spraying. The use of these larger size particles of metal powder permits the reaction to be tempered, that is to say, prevents its going forward too rapidly in localized areas. At the same time, the resultant commingled sprays of metal and bentonite particles in water on the one hand, and copper sulfate-acid solution on the other, tend to remain on the silvered mirror in the form of a mudlike slurry providing ample opportunity for uniform and complete reaction of the chemicals.
Thus, as a typical example of the process of the present invention, I prepare a first solution composed of three pounds of copper sulfate, 5.25 pounds (44 fluid ounces) of 66 B. concentrated sulfuric acid and from about 14 to about 17 gallons deionized water. I then prepare a dispersion composed of approximately two ounces of pulverized iron, all of which passes a ZOO-mesh sieve but all of which is retained on a BOO-mesh sieve, and eight ounces of bentonite (Volclay BC having a pH of from about 7.5 to about 8.5). These two liquid bodies may be separately placed in overhead tanks and flowed by gravity to spray nozzles employing 15 to 25 pounds of air pressure.
The copper sulfate solution may be sprayed at the rate of sixteen fluid ounces per minute and the iron particlebentonite suspension at the rate of five to six fluid ounces per minute at a point of about eight to fourteen inches above rinsed, freshly silvered glass passing thereunder on a substantially horizontal support while the nozzles reciprocate perpendicularly to the motion of the glass and in a plane substantially parallel thereto. Multiple nozzle sets are preferably employed whereby one can deposit as thick a film of copper as desired. The commingled sprays fall upon the silvered surface as a light mud, the mud holding the reagent chemicals in contact and preventing run-off and thereby permitting full reaction of the chemicals.
Successive applications may be made without intermediate rinse, and after passing under as many sprays as desired, the mirror is then rinsed with low-conductivity water, resulting in a copper-clad mirror free from blemishes at either the silver or copper deposits, which may then be used without further coating.
Although I have hereinbefore given a typical example of the process of the present invention and specific amounts of reactants, it will be understood that these proportions of reactants may be varied within the skill of the art.
Thus, the first solution prepared with from about 14 to 17 gallons of deionized Water may contain from about 1 to about 6 pounds of copper sulfate and from about 1 /2 to about 8 pounds of 66 B. sulfuric acid. Similarly, the dispersion of iron powder and bentonite per gallon of water may contain the iron powder in the proportions of from about /2 to about 4 ounces and the hentonite from about 4 to about 10 ounces by Weight.
It will also be understood that variations of the proportions of the copper solution to the iron suspension can be employed and achieved by, for example, varying the nozzle sizes to obtain varying discharge rates.
I claim:
1. In a process of coating a freshly silvered mirror surface with a protective coating of copper by jointly applying to said silver surface an aqueous solution of copper sulfate and sulfuric acid and an aqueous suspension of finely divided particles of iron, the improvement which comprises incorporating bentonite in said suspension.
2. In a process of coating a freshly silvered mirror surface with a protective coating of copper by jointly apply ing to said silvered surface an aqueous solution of copper sulfate and sulfuric acid and an aqueous suspension of finely divided particles of iron, the improvement which comprises pre-suspending said iron particles by incorporating bentonite therewith.
3. The process of coating a freshly silvered mirror with a protective coating of copper which comprises jointly spraying onto said silvered surface an aqueous solution of copper sulfate and sulfuric acid and an aqueous suspension of bentonite and iron particles of 200 to +300 mesh particle size.
4. The process of coating a freshly silvered mirror with a protective backing of metallic copper which comprises applying to said silvered surface a freshly formed slurry composed of a mixture of (a) an aqueous solution of copper sulfate and sulfuric acid and (b) an aqueous suspension of bentonite containing finely divided particles of iron in the proportion of from about 4 to about 10 ounces by weight of bentonite and from about /2 to about 4 ounces by weight of iron per gallon of water.
5. Finely divided particles of iron suspended in an aqueous bentonite dispersion in the proportion of from about 4 to about 10 ounces by weight of bentonite and from about /2 to about 4 ounces by Weight of iron per gallon of water.
6. An aqueous dispersion of bentonite containing finely divided particles of iron stably suspended therein and wherein said particles of iron are from 200 to +300 mesh size.
References Cited in the file of this patent UNITED STATES PATENTS 2,266,638 Hauser Dec. 16, 1941 2,343,158 Scott Feb. 29, 1944 2,759,845 Hilemn Aug. 21, 1956
Claims (1)
1. IN A PROCESS OF CAOATING A FRESHLY SILVERED MIRROR SURFACE WITH A PROTECTIVE COATING OF COPPER BY JOINTLY APPLYING TO SAID SILVER SURFACE AN AQEOUS SOLUTION OF COPPER SULFATE AND SULFURIC ACID AND AN AQUEOUS SUSPENSION OF FINELY DIVIDED PARTICLES OF IRON, THE IMPROVEMENT WHICH COMPRISES INCORPORATING BENTONITE IN SAID SUSPENSION.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16151A US3069289A (en) | 1960-03-21 | 1960-03-21 | Protective backing for mirrors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16151A US3069289A (en) | 1960-03-21 | 1960-03-21 | Protective backing for mirrors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3069289A true US3069289A (en) | 1962-12-18 |
Family
ID=21775658
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US16151A Expired - Lifetime US3069289A (en) | 1960-03-21 | 1960-03-21 | Protective backing for mirrors |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US3069289A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5376431A (en) * | 1993-05-12 | 1994-12-27 | Reflexite Corporation | Retroreflective microprism sheeting with silver/copper reflecting coating and method of making same |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2266638A (en) * | 1938-06-07 | 1941-12-16 | Research Corp | Flexible body |
| US2343158A (en) * | 1942-01-12 | 1944-02-29 | Marquette Mfg Co Inc | Spatter and cleaning shield for electric arc welding |
| US2759845A (en) * | 1954-10-25 | 1956-08-21 | Metropolitan Mirror And Glass | Processes of precipitating copper from copper sulfate solutions and precipitating media for so doing |
-
1960
- 1960-03-21 US US16151A patent/US3069289A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2266638A (en) * | 1938-06-07 | 1941-12-16 | Research Corp | Flexible body |
| US2343158A (en) * | 1942-01-12 | 1944-02-29 | Marquette Mfg Co Inc | Spatter and cleaning shield for electric arc welding |
| US2759845A (en) * | 1954-10-25 | 1956-08-21 | Metropolitan Mirror And Glass | Processes of precipitating copper from copper sulfate solutions and precipitating media for so doing |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5376431A (en) * | 1993-05-12 | 1994-12-27 | Reflexite Corporation | Retroreflective microprism sheeting with silver/copper reflecting coating and method of making same |
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