US 1561650 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Nov. 17, 1.925-
1,561,659 T. H. LASHAR ANTITARNISH COMPOSITIO Filed April 25 1924 Cl. #Mm M INVENTOR Pm@ BY, 'g www ATTORNEYS like.
Patented Nov. 17, 1925.
THOMAS HOLMES LASHAR, 0F CHICAGO, ILLINOIS.
To all whom t may concern.'
Be it known that I, THOMAS HOLMES LASnAR, a citizen of the United States, residing at Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Antitarnish Composition; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enlable others skilled in the art to which it appertains to make and use the same.
This invention reates to improvementsin the prevention of tarnish of silver and other metal articles, and includes an improved anti-tarnish composition as well as articles and structures adapted for use in keeping silver and otherI metal articles from tarnishing.
' lThe problem of preventing or overcoming the tarnishing of silverware and other metal articles is one of the outstanding` problems of the jewelry trade and is a problem whereever Silverware and various .other metal articles are exposed to the atmosphere, as they are in show-windows, show-cases, and the Even where silverware is kept in closed show-cases, the occasional opening of the show-case for display purposes permits circulation of air from the outside-into the show-case, and sooner or later objectionable tarnishing fof the Silverware usually takes place. This objectionable tarnishing is particularly pronounced in cities and towns rhaving a smoky atmosphere, where large amounts of coal are burned, because of the sulfur-containing gases which the atmosphere contains, and for which silver and other metal articles have a special ailinity. In large jewelry stores, or stores where large displays of silverware are found, it is customary to assign o-ne or more men to the work of polishing silverware to remove the tarnish therefrom.v -In the aggregate, the expense and the amount of work involved in overcoming vsuch objectionable tarnishing form a considerable part of the lexpense and labor lofl taking care of such silverware displays. The problem is presented in a some- 'what similar manner with other metal articles, made of other metals .than silver, and is a problemlwith whichv the housewife is confronted wherever silverware is displayed or exposed to the air, since even the air of lthe home, particularly in large cities and where the atmosphere is smoky, contains a lApplication filed. April 23, 1924. Serial No. 708,354.
sufficient amount of sulfur-containing constituents to cause tarnishingl of silverware after varlying periods of time. This tarnishlng of s1 ver, etc. seems to be occasioned not by sulfur-containing compounds alone, but by such compounds when moisture is also present. In a completely anhydrous atmos` phere, even considerable amounts of sulfurcontaining constituents in the air may be without objectionable tarnishing effect, even after prolonged periods of time. Moreover, apparently Sulfur-containing gases and particles in the air have an affinity for moisture, such that moist air, when laden with sulfurcontaining gases, appears to be much more objectionable because of its tarnishingpros pensity. f'
Because of the heat conducting properties of metals, -metal surfaces afford attractive surfaces. for the condensation of moisture thereon. If, for example, the air is warmer than the metal Surface, the cooler metal surface will tend to condense moisture from the air immediately adjacent to it, and there will tend to be formed an adsorbed or absorbed ilm of moisture on the metal surface. It is perhaps for this reason that sulfur- .containing gases are so objectionable when moisture is present, for if the moisture which is condensed on the metal surface carries sulfur-containing gases which are condensed with it, these gases can then attack'the silver or. other metal surface in the presence of suiiicient moisture to permit the formationof a black film of silver sulfide,
nishing is due.
The present invention provides an improved anti-tarnish composition, and .improved articles or structures embodying or to the formation of which objectionable tar'` combined with such anti-tarnish composition, whereby objectionable tarnishing of silver, etc. can be prevented for long periods of'time, in a particularly effective manner.
It is well known that aqueous solutions of different metal salts, when brought into contact with hydrogen sulfide and other sulbecomes Aof little or no value. Moreover, if
water .is present considerable amount inv Show-casesand Similar `places where jewelry and sllverware are .commonly kepton dlshydrogen sulfide, etc. from the air which comes in contact with them, but I avoid aqueous solutions of such salts, and, 1n-
stead, I use solutions of such salts innon-l volatile solvents which are moreover hygroscopic and which tend .to remove moisture from the air of the show-case or other place, as wellas the sulfur-containing compounds which the air contains.
I have found that the objections and limitations of aqueous solutions of such metal salts can be overcome, and new' and advantageous results obtained, by dissolving the metal salts in a non-volatile solvent such as glycerine, etc., in which the metal salt is soluble, and which itselfv has hygroscopic properties or an affinity for 'water-vapor and water. The new composition of the present invention, accordingly, is a solution of a metal salt, such as lead acetate, in a non-volatile solvent, and particularly in such a solvent which has hygroscopic properties.
Different metal salts may be used in the composition of the invention but I have found that lead acetate is particularly effective. 4Other lead salts, however, can be used and even salts of other metals.
The solvents which are used may contain some water, but I have found it advan- 'tageous for best results to use a solvent which is free or relatively free from water, such as a polyhydric or polyhydroxy derivatives, especially glycerine, although other compounds such as glycols can be used,'or even aqueous solutions of glucose. Glycerine not only has the property of dissolving lead acetate, for example, but in view of its hygroscopic properties, it tends to attract moisture from the air, and, in this way, when exposed to the air, tends not only to remove sulfur compounds such as sulfurated hydrogen, but also to keep the air' dry. Since the' particles of sulfur compounds tend to associate themselves with and to deposit on the particles of water'f'vapor in the atmosphere, the presence of a substance such as a glycerine solution of the metal-salts tends to draw to it the particles of water-vapor with thesulfur particles attached thereto so that the sulfur particles react with the metallic salts dissolved in the glycerine to form a metallic sulfide, instead of condensing on the metal surface and tarnshing the metal.
The 'new composition, containing the metal salts dissolved'in a non-volatile sol# vent, can be used in various ways. One advantageous applicationof the composition is for impregnating a fabric to provide' an pounds is exposed to the impregnated ma- 4 terials. Absorbent materials such as kieselguhr may be used to absorb the solution.l
I have found that compositions containing the lead acetate dissolved in glycerine are radically more effective than lead acetate when used in water solutions, wherethe water tends to evaporate and leave a dry residue ofthe lead acetate.
The nature and advantages of the inven tion will be further illustrated by the following examples and more detailed description.
One composition which I have found most satisfactory is made by dissolving lead acetate in glycerine in the proportion of about 1 lb. of lead acetate to'l pint of glycerine without the addition of any water thereto. The dissolving .of the lead acetate in the glycerine lcan advantageously be carried out by placing for example 5 gallons of glycerine (using'either chemically pure yellow distilled glycerine or a crude glycerine) in a copper tank, heating to about 155 F., then adding the powdered lead acetate, and stirring until the lead acetate is dissolved. After the leadv acetate is dissolved, the temperature of the solution can be lowered to.
about 130 F., but for the impregnation of fabric, etc., the temperature should not be permitted to drop below about 100 F., as the solution becomes too thick to use readil if it is cooled below approximately suoli temperature.
In -kusing such a solution for the impregnation of fabrics, a pad of felt; or other fabric can be dipped in the solution while heated to a temperature above 100 F., e. g. around 130 F., and the impregnated fabric can then be passed through a wringer. The pads, particularly if made of porous material such as felt, can' then be hung up for a period e. g. of about 48 hours to -allow the excess solution to drip oit from Instead of using glycerine alone for d'rsy l solving 'the lead acetate, I have also used an aqueous glycerine solution containing vary-v ing proportions of water and glycerine. For example, a 25 per cent solution of glyc- .solved without the necessity of using such high temperatures as referred to in the preceding example. d
In Iusingsuch an aqueous glycerine solution for treating felt pads or fabrics, the
' p-ads can be dipped in the solution,r then Y Il, themselves contain objectionable sulfuf coin.
ypleted by hot air-"or -ina tumbling wrung and then dried in a blast of hot air to remove the water and leave the glycerine' solution of the fabric.
For certain purposes, I find it more adif'antageous t-o use a still more dilute mixture, containing, for example, 1 pint of `glycerine in each ga.llon,'or'even less glycerine, and 2 lbs. faceta't'e of lead per gallon; Such a solution can advantageouslybebsed for treating box linings, curtains and other y.ina-
the lead acetate impregnating terial which may come in direct contact withy the silver. Box linings for examplegmay be dipped in the solution, then wrung out, and then put in a rotating extractor `to`remove moisture, and the drying may then be combarrel heated by a hot air blast. y
The composition can be used for rendering materials anti-tarnishing where they pounds. l Where, for example, paper, string and otherl substances', or` material suoli as glue, which areused with silverware and tarnishable metals, are to be rendered antitarnishable, they may be analyzed to determine their sulfur content, and they may then be treated by the .composition of the present inv'ention'to destroy their tarnishing properties, so that they can then be used without danger of causing tarnis-hing of the silverware or other articles with which'they come' 'in contact.
The formulae and compositions referred to above,y and the special methods of'their application, are typical and illustrative of the invention. The particular proportions' of the ingredients, and the nature ofthe formulae, can be varied somewhat care of varying conditions.
,Instead ofusing fabrics for carrying the composition, cardboard pads may someto take times be used, the pads being dipped, wrung and then placed in a wooden rack with air space and allowed to dry fora sufficient time. Where the composition contains water,y and the fabric or other-'material is impregnatedwifth it, the excess water can be subsequently removed by heating to a sufficient temperature for a suitable periodV of time.
l Y Where the glycerine Iis used alone without for example be from 130 F. to 17 5 F., a
though I have found a temperature of about 155"l F. to be suitable for making a solution to be subsequently used for impregnating the fabric in the manner described.
In protecting show-cases and 'the like I have found it` advantageous Ito use a feltpad of appreciable thickness impregnated with the new composition. Other fabrics or other absorbent material can however be used, such as cotton, paper, wool, wicking, charcoal, hemp, kieselguhr, etc. Feltpads, however, have an appreciable thickness and oa'n retain a considerable amo-unt of the composition so that they are effective o-ver relatively long periods of time. The felt pads may advantageously be placed in pad holders or frames so that they caribe readily handled, and these frames can advantageously be attached to the under side of the shelves of the show case or cabinet so, as
to take up a minimum amount of room in ther show-case, and so as not to interfere with the display of merchandise in the showcase. As distinguished from a dry fabric,
the impregnated pad or fabric of the prese-nt'invention, where it contains a considerable amount of they composition of the 1nvention, has a somewhat -moist feel, and
some of the composition may be rubbed off containers can be used in which an `absorbent material .is treated with the composition and stored in such a way as to come in'contact with the air which the container holds. Such a container may have holes in it which will allow the air toenter, so..y that, through these holes, the air has laccess to the composition and can come in contact with the treated absorbent material. Bowls containing the anti-tarnish composition of the invention can also be used together with a wick-like substance such as hemp or charcoal which will serve -to present to the air an extended tion. y
The use of the new composition of the invention when properly distributed and exposed to the atmosphere of a show case and the like, provides a novel and improved method for purifying the air ofthe shouopened by people entering and leaving the store., and where the show-case is being more or less frequently opened for the display of merchandise, to wash the air or purify it so surface carrying the composii that the air contained lin the storeand inA which has an athnty for moisture. In the processof the invention`,accordingly, and
in using ,the composition of the invention, .the air is. subjected to a combined drying :and desulfurizing treatment by acomposltion which has an absorptive attraction for both moisture and sulfur-containing vapors- This puriiication of the air serves to protect the silverware and other metal articles' from tarnishing because the moisture and sulfur-containing vapors which would otherwise tend to separate out on the metal surfaces are instead attracted to the hygroscoplc and sulfur-compound-neutralizing composition of the invention. Since a sul- Afur-containing gasv naturally tends to deposit on, or dissolve in, Water' vapor, and since the latter is in turn attracted to, and held by, the composition of the invention, particularly when distributed over the surface of a pad or other material, it may be said that the composition of the invention exerts a preferential aflinity for moisture and for sulfur-containing vapors, and consequently brings about an e'ective removal of sulfur-vapors and of moisture from the air, and thereby protects the silverware and other metal objects from tarnishing.
The advantages of both drying the air and absorbing sulfur-containing ases, as 'compared with absorbing sulp ur-containing gases without drying the air, or absorbing ,certain gases by solutions. which increases lthe humidity of the air, will be appreciated when it is considered that dry gasesl such as hydrogen sulfide do not react readily with, or bring about, a tarnishing of metals, while the presence of moisture promotes such tarnishing When such sulfur-containing comunds are present. lhe composition of the invention may therefore be considered to prevent or retard tarnishing by keeping the air d as Well as by absorbing .the objectionab e sulfur-containing gases and com-V pounds and thus protecting the metal surfaces 'from them.
In the commercial application of the invention, the particulanform in which the composition, or articles carryin or impregnated by the composition, will used will vary with the conditions where the composition is to be used. By coatin a wood or other surface with the composition, the composition can beapplied without the use of a fabric or similar absorbent. For eX ample, the under side of a shelf in a `showcase, if adapted for holding a coating of the com-position, can die painted or coated with the compositionand this composition Will protect the air of the show-case and the silver articles in the show-case for considerable periods of time'. A porous board of Wood or otherl material can similarly be painted with the composition and hung up position of ,the invention.
Fig. 2 shows such a pad supported in a frame.
Fig. 3 shows a further method of supporting such a pad.
F ig. 4 shows still a further method of supporting the pad, and
Fig. 5 illustrates a show-case with the mvention embodied therein. A
The pad of Figs. 1 4y may be a felt pad. dyed black for example and impregnated with the composition of the invention, for example, according to the lirst speclic example hereinbefore given.
Figs. 2, 3 and 4 show various methods of supporting and holding the pad in a frame or support. In Fig. 2 the pad 1 is held between a top member 2 which may be a thin board or cardboard, and a bottom ,frame member 3 `which holds the edges of the pad. In Fig. 3, the upper member 4 may be an ordinary board or cardboard and the lower member 5 is a perforated board or cardboard having perforations permitting the access of air to the4 impregnated pad. These membersmay be held togetherv in any suitable way. Inl Fig. 4 the pad 1 is held betweenthe upper member 6 and the frame member 7 anda screen 8.is provided for assisting in 'supporting the pad .while permitting access of the air thereto. l
Pads of this kind can be supported as indicated at '14, 15 and 17 in Eig. 5,fattached to the under side of the shelves 12 and 13 or to the doors of the cabinet 9 having front and top glass members 10 and 11 and doors at the back for permitting access to the cabinet or show-case. A pad 16 is shown as supported in the upper portion of the showcase or 4c abnet,.this pad vbeing merely depending-and supporte-d at its upper end, or being a wick-like .structure and having one end depending into a container containing the composition. y
In suc-h a. show-case, the air within the show-case, while relatively quiscent, is nevertheless more or less in motion, while the opening o-f the door permits access of .fresh alr from outside'and also serves to stir up and set in motion the air within the showcase. In such a show-case, however, 'the pad containing the composition of the invention lWill exert its hygroscopic action upon the air and will tend to keep it dry, while the metal salt in solution will be exposed in a reactive state to the air in the show-case and the sulphur-containing compounds will be attracted the-reto and will be absorbed and held thereby. The hygroscopic nature of the glycerine 'solvent promotes the reaction o f the. sulphur compounds contained in the air with the lead salt, both by attracting moisturelwhich assists inthe reaction, and by attracting moisture which may already have combined with and which carries the sulfur-containing compounds themselves.
It will thus be seen that the present invention provides 'an improved composition as well as a felt pad or other absorbent material impregnated therewith or treated there- With, and structures such as show-cases, cabinets, etc. in which the composition is provided to protect the structures and particularly to protect the silverware and tarnishable metal articles therein. It willv further be seen that the invention pro-vides an improved method of making the composition aswell as an improved method of using the composition and of saturating or treating fabrics and other materials therewith, and
an improved method of protecting jewelry, silverware, etc. from tarnishing and for purifying the air of show-cases and other structures from sulfur-containing constituents having tarnishing propensities. K y
The novel composition of the invention, as
. hereinbefore pointed out, contains a metal salt such asv lead acetate, dissolved in a` solvent which is non-volatile and which has vhygroscopic properties', which solution is used for treating or saturating or impregnating various fabrics or absorbent mate- Lrials to give protective surfaces which when exposed to the air will serve topurify the air in the manner hereinbefore described.-
1. .A new anti-tarnish composition -comprisingl a solution of a metal salty capable of absorbing hydrogenlsulfide ina hygroscopic non-volatile solvent.
2. A new anti-tarnish composition` comprising a solution of a metal salt capable of absorbing hydrogen sulfide `in a poly-hydroxy compound.
3. A new anti-tarnish composition comprising a solution of lead' acetate m glycerlne.
. 4. The method of making an anti-tarnish i Icomposition which comprises dissolving lead 1- acetate in glycerin@ at an 'elevated temperature,
5. A new article or composition comprismg an absorbent material carrying a solution of a metal salt-capable of absorbing hydrogen sulfide in ayhygroscopic organic solvent.
6. A new articlev or composition comprising an absorbent material carrying a solution of lead acetate in glycerine.
7. A fabric impregnated with a composition comprising a metal salt capable of absorbing hydrogen sulfide and a hygroscopic organic liquid.
8. A fabric impregnated with an anti` solvent and a support for supporting said l absorbent material so as to expose the antitarnish composition to the air.
` 10. A fabric impregnated with a solution of lead acetate in glycerine, said fabric having a supporting frame or support.
11. A show-case or similar structure having therein, exposed .to the air therein, an anti-tarnish composition which is both hygroscopic and capable of absorbing sulfurcontaining constituents from the air.
12. A show-case or similar structure for containing silverware and the like, having. therein an extended surface, carrying a hygroscopic composition containing a netal salt capable of absorbing hydrogen sulfide, said composition being capable of absorbing both moisture and sulfur-containing constituents from the air. r
13. A show-case or other structure adapted for containing silverware and the like, the interior of such structure having an extended surface in contact with the air of the i show-case, which surface carries a solution of a metal salt capable of absorbing hydrogen sulfide in a hygroscopic organic solvent.
14. A show-case or other Structure adapted for containing silverware and the like, the interior of such structure having an extended surface in contact with the air of the show-case, which surface carries a solution of lead acetate in glycerine. I
15. A show-case or other structure adaptedk for containing silverware and the like, said structure having therein a fabric exposed to the air and which fabric carries a composition comprising lead acetate and glycerine, said composition being hygrcscoplc and capable of absorbing both moisture from the lair and sulfur-containing compounds from droxy organic solvent at au elevated teraglycerine, treating an absorbent materialV with such solution, and drying the-resulting product to remove water therefrom.
18. `The method of preparing an anti-tarnish fabric which comprises` treating the fabricl at an elevated tem erature with ra non-aqueous solution of lea acetate in glycerine, and removing the excess of the solution.
19. The method of preparing an anti-tarnish fabric which comprises treating the fabric with a solution of lead acetate in aqueous glycerine, and subsequently drying the fabric to remove water therefrom.
20. The method of preparing an anti-tarnish fabric which comprises dlssolving lead acetate in an aqueous solution of glycerine.
vtreating Ithe fabric with such solution, re-
moving the excess of such solutiony and drying the fabric to remove Water therefrom.
21. The method of purifying air in showcases and similar structures for the protection of silverware and the like from tarnishing,.which comprises sub'ecting the air in such structures to the puri ing action of a hygroscopic composition containing a metal salt capable of absorbing hydrogen sulfide, said composition being adapted to absorb moisture from the air and also to absorb sulfur-containing constituents from the air.
22. The method of purifying the air in show-cases and the like for the protection of jewelry, etc. from tarnishing, which comprises subjecting the air in such structures to` the purifying action of a solution of lead acetate in glycerine, said solution being hygroscopic and absorbing moisture from the air and also absorbing sulfur-containing constituents from the air.
In testimony whereof I aflix my signature.
'rHoMA-s HOLMES LASHAR