US 2112762 A
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Description (OCR text may contain errors)
March 29, 1938. c. B. cHATFu-:LD 2,112,752
MARKING BOARD AND CRAYON THEREFOR INVENTOR CHAEL ES 5 CHA TF/ELD.
BY M l M A TORNEYS Patented Mar. 29, 1938 UNITED STATES -PATENT OFFICE 18 Claims.
'I'his invention relates to a marking board which may re place the customary blackboard and a crayon for use thereon.
Blackboards, whether of slate or of composition, used with chalk crayons have well-known disadvantages. They must have abrasive surfaces. In the case of the slate the surface is naturally abrasive and under the microscope shows pits with'jagged edges covering the entire surface. In the case of artiilcial-or composition blackboards, abrasive such as slate, emery or corundum powder are added to the surface composition to give the necessary jagged edges which project from the surface of the composition board. These abrasive surfaces must be present in these boards in order to scrape oil vand hold particles of the chalk crayon which has little, if any, adhesiveness for the blackboard surface, but upon being scraped oi by these minute abrading surfaces iills the pits or spaces between the abrading edges to give the appearance of a continuous mark. The weak4 friable nature of the chalk causes it to dust during writing, for only a portion of the chalk that is abraded from the chalk crayon adherestto the board and the rest of it flies in the air or adheres to the flngers or the clothing. 'I'he written or other marks on blackboards are customarily erased with a dry eraser which causes worse dusting than the process of writing for much of the chalk removed by the eraser does not remain -on itbut flies in the air. The chalk dust so released is a nuisance and may be a menace to health. In addition, the
legibility of white or other color on a black background is not as high as certain colors on white or light backgrounds. The scale of legibility appears to be somewhat as followsz-black on yellow, green on white, blue on white, all of which are more legible than any marks on a black background. In addition-blackboards after constant use assume a grayish cast which makes writing thereon with white chalk reven less legible. In addition -to these disadvantages, blackboards absorb 'considerable light so'that a wall lined therewith reflects into a room acorrespondingly smaller amount of light.
It is important in using the usualI blackboards, as mentioned above, to provide a' chalk crayon. These crayons are for the mostpart composed of natural or artificial mineral substances, such as calciumcarbonate, clay, gypsum, plaster of Paris, talc and the like to which pigments are sometimes added to give a desired color.' The crayons are made up by compression with-or without binders, or cast in molds as in the case of plaster of Paris. As so prepared because of their friable character they may be used for writing on the abrasive blackboards as mentioned above. Crayons which are not friable and which would overcome the objectionable dusting men- 5 tioned above, are not feasible for writing on abrasive blackboards because they tend to fill up thepits or abrading surfaces and cannot be relmoved or would be removed with diillculty by the usual felt ersers. y 10 The principal object of the present invention accordingly is to provide a writing struct'ure and crayon which shall do away at least to some ex- -tent with the mentioned disadvantages of the combined blackboard and chalk crayon, and particularly'to providel a board and crayon which shall b e substantially free from dusting and which shall produce writing or other marks of a more legible character than heretofore obtainable on blackboards and which shall permit easy repeated marking and erasure and which shall give improved light reecting characteristics. Another object is to provide a board or slmilar structure and' crayon having the desired characteristics and which may be easily and inexpensively manufactured. Other objects and advantages will more clearly appear in the detailed description hereinafter set forth.
The invention accordingly comprises the novel 'devices and products and combinations thereof. 30 specific embodiments of which are described hereinafter by way of example and in accordance zvith which I now prefer to practice the invenion.
In the accompanying drawing, which-is made part of the specification, I show embodiments of the invention as I now prefer to practice it. In the drawing- Fig. 1 shows a panel board made up of cementasbestos board or wood fiber board, etc., on which is a coating of vinylite or other resin containing pigment, on which panel board a crayon containing triethanolamine soap and pigment or like y material is employed;
Fig. 2 shows lanother type of panel board composed of wood fiber board or chip boardor other paste-board etc., on which is a laminated sheet of opaque white, yellow or other colored lithopaper, over which is another lamination oi' clear vinylite or other lacquer or a sheet of cellulose acetate or other cellophane.
I have found in accordance with my invention that the above objects, among others may be accomplished by the combination of a panel drawing board, which is opaque or nearly opaque, having a glazed of a non-abrasive character substantially without roughnesscs except for poa- 'sotnatitwmnotbreakirdmppedimmaheisht of labout four feet. and whose is tam when applied to the glazed surface mentioned, which crayon'do not soften or harden appreciably at temperatures in a range of 15 l". above or below room temperature, the combinationbeingsuchthatthecrayonwilldepoaiton said surface clearly legible marks with about the same drag as that of a soft lead pencil if applied to ordinary writing paper, but which may be removed by simple rubbing without abrasion, such as occurs in erasure of lead pencil marks from paper, with a soft cloth, for example soft cotton, wool or paper (such as Kleenex) withoutappreciable smearing or stain left on said surface. 'I'he board and crayon combination is adapted for repeated marking and erasure without losingvthe l characteristics mentioned.,
In the appended claims where the expression panel drawing boar is used, I refer to a panel board vattached to a wall replacing the ordinary blackboard for marking, drawing, etc., as well as a smaller'type of structure mounted or unmounted and serving to replace the ordinarysmall blackboard or writing slate.
The usual hand crayon size, which I have referred to in the appendedclaims, is of approximately 1'; inch diameter and 3 to 4 inches long. It is to be understood that ,the crayons of my invention are not restricted to such size but may be of any practical size. Hand size crayons heretofore known -to me are required to be encased in paper or otherwise. My crayons in such size, however, are suiilciently strong in themselves so that they may be used unencased for hand markum y s.
I prefer to employ a'y panel drawing board of opaque or nearly' opaque material comprising a relatively hat` foundation and a smooth glazed coating adhering to the face of the foundation, the foundation and coating being suiliciently stiff inherently to permit marking by a crayon thereon. 'I'he foundation may be of cellulose-con taining material such as pasteboard or the like,
or cement or sheet metal, molding resin or like material. The coating is preferably of vinylite or cellulose ester, casein or like material either in sheet form or applied as a lacquer. I'he crayons preferably contain hardening, lubricating and tacky materials and are ordinarily and preferably produced by a hard soap, stearic or like acid, and triethanolamine stearate or like substance. If desired the stearic acid may be omitted altogether from such a composition.
'I'he character of the 'surface of the panel drawing board on which the writing occurs and the character of the crayon employedaccording to my invention, are interdependent. For example, the glazed surface of the panel board can be marked on by an ordinary soft lead pencil, but
after such marking is made it is practically imv possible to remove it easily without washing the surface. On the otherhand the usual wax cray- -onsonthe-marketaregenerallytcohardtobe ariavcs Y perature above and below vordinary room temperature, but are correspondingly .too hard for suitable marking on the glazed surfaces of myl invention. Varyingv the proportions of their ingredients may make them more tacky but they then melt too' easily and are not adapted for free writing, andr have not sufiicie'nt inherent strength. The glazed surface ofmy invention, therefore, requires a special crayon. So far as the crayon itself is concerned, it of course is adapted for writing on surfaces other than, glazed surfaces. Por instance. it can be usedfor writing on slate or porous materials, but if so used it sinks into the vsurface of the slate or similar hard porous material and it is practically impossible to remove it by ordinary erasing means. The same is true of paper surfaces which depend somewhat on the abrasive action of their ilbers to remove particles of graphite from lead pencils or crayons applied thereto and must be erased by abrasion at least in part. My crayon, however, is intended especially to be used on my glazed surface board, and the adhesive tacky material forming these marks is `such that it will adhere'to, the glazed surface without causing any dusting or crumbling but when a soft cotton cloth is run over it. the cloth has greater adsorption for the crayon material than the glazed surface has for the crayon material, and consequently the crayon is easily removed by gentle rubbing without .abrasion.
In forming the board, as mentioned above, a suitable foundation or backingis prepared and on this a glazed surface is applied by any suitable method of application such as by brushing,` spraying, dipping, flowing, rolling or printing or the surfaces maybe applied as a sheet. As noted above the foundation of the board may be of pasteboard or various other materials, the foundation 'and coating being suillciently stiff inherently to permit marking by crayon thereon. The size of the article may to some extent determine the method of application and this size may range from the smallest memorandum slip to that of a board such as a blackboard covering a whole wall area.' The size of the article may also determine the type of finish to be applied or built up, thus a high gloss surface is not objectionable in a small telephone .memorandum pad which may be easily moved about in order not to reflect light disagreeably into the writers eyes. A high gloss onthe other hand might be very objectionable if it were to replace the customary blackboard in a schoolroom, and for this purpose an egg-shell or flat finish is used and reflected light is dispersed in such a way that the schoolroom is lighter and written marks on the board are legible from all angles.
Referring now to the drawing and particularly to Fig. l, there is shown a panel board which is made up of an underbody of cement-asbestos or wood fiber board or other suitable material, i, on which is placed a coating of 'vinylite or other resin 2 containing a pigment. This board may be used with a crayon composed of triethanolamine soap or similar material andv pigment contrasting with the board in color. In Fig. 2 another-1 type.- of panel board is shown comprising three layers, the underbody 4 of wood fiber, etc., on which is superimposed a laminated sheet of opaque white, yellow or other colored litho-paperi. Over this is placed a coating of clear vinylite or other lacquer or a sheet of cellulose acetate or other cellophane 6. With this may be used a crayon 3 vsimilar to that described in Fig. 1 or other type of crayon.
The following specific examples are embodimarking with a hand crayon.
Eximruzs or Bonus Example 1 In order to produce a panel drawing board of inexpensive construction which may be vframed and employed as an easel board or similar board,
White cardboard is laminated with chip board by means of cold or hot glue in the manner ordinarily used by pasteboard box manufacturers. Upon this laminated structure a viscose cellophane sheet is superimposed and cemented on the face of the white cardboard by means of a nitrocellulose lacquer or similar cementing material. The resultant product is a laminated structure consisting of cellophane over white cardboard over chip board producing an opaque or nearly opaque appearance with a glazed surface of a non-abrasive character. The surface is substantially without roughnesses, except for slight undulations, and is of sufllcient stiffnessto permit marking thereon with an unctuous crayon of the kind herein described. The surface may be marked on with blue or other contrasting colored crayon and the marking may then be easily erased by rubbing with a soft cloth which does not abrade the surface but simply absorbs the crayon without appreciable smearing.
Instead of the chip board I may employ wood -ber board or brown pasteboard, and instead of the cellophanesheet of viscose' I may employ cellulose acetate orV the vinylite type of cellophane sheet.
Example 2 Where the foundation of thel panel drawing board is to have a border design representing the `margin of a nnished drawing board, or where it is to be printed with the alphabet, numbers or any other desired design, I preferably use white litho paper on which such border or other design is printed. 'Ihis is then laminated with a vinylite or other sheet on the customary machines for this purpose, using any desired ceinenting material. The roll of printed litho paper laminated with the vinylite sheet is then cut into any desired size by a paper cutting machine and is lfurther laminated with a brown pasteboard back to give it the desired stiffness for The result is similar to that given in Example #1.
Instead of the wood liber board, I may employ pasteboard and instead of the litho paper I'may employ glazed unprinted finished paper of any color and the vinyliteV lacquer. may be applied by dipping. In making up this form of panel drawing board the pasteboard is laminated with the paper and when the cementing material has set the laminated sheet is dipped finto a vinylite solution of the proper consistency, removed, drained and allowedto dry.
' Example 3 Instead of the structures given in the above examples, I may employ wood fiber board asv the foundation and apply on it a vinylite solution containing a white pigment such as zinc or titanium oxides, The wood fiber board issanded to remove protuberances, surface scratches, etc., and the vinylite solution containing piment is then applied to this by any of the ordinary methods such as by brushing, spraying, ilowing, roll-coating. Enough material is applied in one coat to give the desired smoothness or covering, or if necessary two or more coats of-a thinner consistency may be applied if desired to give the glazed coating like that of Example #1, on the panel drawing board.
Example 4 A panel drawing board which may be used as an easel board or which may be attached to a wall,
may be made as followsz-Cement-asbestos board is sanded to give a smooth surface, is sprayed with a vinylite primer solution containing a pigment and the sprayed board is then placed ina heated oven of any desired temperature, say 140 F. When dry the board is sanded again and vrez-coated with the primer solution and dried as before and resanded. A vinylite nishing solution containing white or 'other pigment is then applied-'by spraying and the drying and sanding operations repeated. A second or third coat of finishing' solution is then applied and dried. No further sanding operation is necessary and the resulting surface constitutes the desired glazed surface. 'I'he pigments employed may be of any desired color. For white I prefer to employ titanium oxide, for blue an ultramarine blue, forred a toluidine toner, for black I may employ carbon black. Other colored pigments may, of course, be employed. Instead of drying the material after the primer coating at elevated temperatures, it may be dried at ordinary temperature and coating material maybe applied by other means than the spraying. The sanding operations are preferred in order to give a thoroughly'smooth surface,butmaybeomittedifa sufficiently thick coating is applied so that the nal glazed surface is substantially free from roughnesses and abrasive characteristics.
This board so prepared is suitable for an easel board. It may be framed if desired.` I also prefer it as a wall panel. A board prepared as above may be fastened to a wall by any of the usual methods such as with an adhesive cement or by other means of direct attachment as nailing or by enclosing it in a framework attached to a wall.
Example 5 'examples. For example I have successfully employed a casein solution as a coating. The casein is preparedby adding toV 1 gallon of water heated to'about 158 F. l pound of casein. The mixture is stirred for about ve minutes or until the casein is fairly well swelled. V4 pound of borax is then added and the mixture stirred until the casein is thoroughly dispersed. Smooth white cardboard is then dipped into the casein solution, further diluted with water to' give increased flow if desired. removed and the excess allowed to drain off and dried lat room temperature. cardboard is preferably yoi' suillcient inherent stiffness and with the coating of casein to permit marking thereon. One or more coats of casein ay be given and the casein may be used with or without pigment. The resulting Surface isthe decrayons herein described.
Instead of white cardboard I may employ for example yellow cardboard suitable for bridge scores and coated with a transparent glyptal resin lacquer or varnish. 'Ihe cardboard is of suiilcient stiffness to permit marking thereon and v the scores may be made thereon and erased repeatedly.
' Example 6 A somewhat more expensive type `of board may heV made of a sheet metal suitably treated. For example a piece of sheet metal such as iron or aluminum is coated by any desired method with spar varnish paint containing la pigment such as chromium oxide green and when dried is given a ilnai coat of clear bakelite, alkaliand acid-resisting varnish. It may be then air-dried or ovendried as desired, and the surface will be found to have the desired nnlsh.
Instead of the metal coated in this manner, I may employ such sheet metal with a vitreous white opaque enamel coating such vas that employed on enameiled cooking utensils or bathtubs, and applied by tiring to give a glassy surface to the metal. Instead of the metal base I mayemploy a sheet of polished glass for the panel drawing board, the glass being coated on one side with suillcient iinseed oil paint, containing for example yellow pigment such as lead chromate ,to make `the glass substantially opaque. 'I'he uncoated side then provides a satisfactory glazed surface. Such a structure is relatively rigid and expensive. In place ,of it I may employ a molded resin such as -urea-formaldehyderesin. In making up a struc- The spray-coat is formed of cellulose ester lacquer such as cellulose acetate or nitrocellulose lacquer and a sumcient quantity is applied to' make it smooth and imperviousto the crayon. I prefer for this purpose to give theA cloth a number of spray coats. 'I'he coat may be pigmented or not as desired. I usually prefeto add a pigment. A
sumcient thickness of coat is given so that the surface has the desired smooth unroughened and non-abrasive character suitable for use of the crayon herein described. After preparation of this cloth, it may be attached to a shade roller for use as a roller panel board..
Example 8 As a toy I may Vemploy an ordinary good grade of magazine paper printed with la line-drawingpicture of a bird or4 other animal. The paper is sprayed with `a clear. vinylite lacquer or varnish making it possible fora child to fill in the colors of the animal with the crayons herein described, erasing these and repeating /the process at will. The assembly is of sufficient stiffness so that it permits the repeated marking and erasure of the crayons herein described.
Example "9. Y The usual slate or composition wall blackboards in general use may be treated to render -and the like.
above. For example the ordinary them satisfactory foi use in accordance with `my invention. For example, a natural siateblackboard fastened to a wall of a'room by' any of the usual means such as adhesive cement `or by nailing or by enclosing in a framework 'attached to a wall, is first cleaned with dilute hydrochloric acid or other cleansing material and the surface is rubbed down to remove the larger abrasive protuberances and \sprayed with a priming coat containing a colored pigment such as yellow ochre or a pigment of any color suspended in a properly plasticized vinylite solution. This spraying may be followed by one or more sprayed finishing coats with or without a pigment, the vehicle of which consists of a vinylite solution properly plasticized. By this means the board is 'transformed into a panel drawing board, having the desired glazed surface and other characteristics of my invention.
The boards may be of various colors as noted in the above examples, but I` prefer for general purposes light colors such The' crayons to be'used with the above boards are of an unctuous type which when their.writ
ing point is applied to the glazed surface of the board will be sumciently tach so as to leave clearly legible marks which may be repeatedly as white, cream. bui! applied and repeatedly erased without substantial staining. These crayons contain a substance,
or substances' which provide av hardening, lubrieating and taclqr characteristic therein, but in proportion preferably so 4that the crayon does not soften or harden appreciably at temperatures in a range of about 15 F. above or below room temperature and so that 'when the crayon is applied to the surface it has about the same drag as that of a soft lead pencil when applied to the usual writing paper.
I have discovered in accordance with myv invention that a crayon suitable for my purposes may be made of a solid solution of water-soluble soaps with an appropriate color added. I prefer to employ ordinary hard soap such as sodium oleate or sodium palmitate or sodium stearate,
or mixtures of these, dissolved in a substance of acid nature such for example as stearic acid or acid resin or gum. at 'slightly elevated temperature, reacted while molten with an alkaline substance such as triethanolamine and/or otherL ethanolamine added insufficient quantity to react with allor most of the acid material presy ent, thus forming a triethanolamine soap with the acid substance. To the. resultant mass a dry colored pigment' or dye, may be added or incorporated in the soap. Examples of other acid materials which may be employed, are as-v phaltic materials, beta-naphthol tar, resins such' as shellac, dammar gum, rosin, naphthenic acid,
synthetic gums and resins. I prefer to have an' fss\ the kind of alkaline material used to combine with acidic substances such as those mentioned ommercial grade of triethanolamine customarily contains in addition to triethanolamine approximately 5% of monoethanolamine and 17.5% diethanolamine, either of which constituents may be used alone or together to produce desirable results. `Thehomclogues of the ethanolamins, having. proper agitation may be mechanical or by hand but` itv ties similar to the ethanolamines, may be advantageously used. Instead of using the chemical derivatives which are related to the mono-hydric alcohols, substances related to the ethanolamines and similar to' them but derived from the dihydric or polyhydric alcohols such as the glycols, glycerine and thelike may be use'd. In fact various organic basic materials may be used in combination with organic acid materials to produce useful substances 'similar to the soaps, for example dimethyl aniline in combination with oleic acid. I have also found Athat a crayon for repeated marking and erasure may be made from a solid mixture of a triethanolamine soap and a coloring material. y y
Also, in place of a soap, I have found that it is possible tb use the so-called water-soluble waxes such as the glycol stearates, dihydroxyethylamine linoleate, etc. For the soap I have also found that sulphonated oils and waxes, such as the sodium salt of sulphonated castor oil, or sulphonated tallow, and the like may be used to advantage. Also these sulphonated oils and waxes when uncombined with an alkali may be used as the acidic substance in'my crayons.
In the practice of the invention it is often desirable to obtain certain physical characteristics in the crayon which can be obtained by the addition of a conditioning or tempering agent. By conditioning or tempering agent is meant an added substance which is not in itself a soap but which is added to the mixture of soaps in order to make the mixture harder or softer or which gives the crayon less or more drag, or other desired properties. It is generally possible to obtain the desired physical characteristics by changing either the acidic substance or the type of soap used but at times it is desirable to use a certain mixture of soaps which do not give the exact physical characteristics desired and the use of conditioning agents is important. These conditioning agents may be waxes in the nature of paraflin wax, b eeswax, carnauba wax, halowax and the like, and mineral extenders or llers such as blanc'fixe, or soapstone and the like.
The examples lof crayons given below are embodiments of the invention as I now prefer to practice it with the panel drawing boards above. It is to be understood that the invention is not to be restricted thereto except as indicated -in the' appended claims:-
EXAMPLES or CiiAiroNsr Example 10 25 pounds of ordinary` commercial hard soap flakes of either Ivory soap or Palm Olive soap,4
are dissolved in 22 pounds of melted stearic acid. This solution is eected in an open or closed kettle with any appropriate source of heat and the mass is agitated during dissolving. The
is importantthat the soap not be permitted to stick or burn to the bottom or sides ofthe kettle..
When all of the soap has gone into solution and while continuing the stirring 8.8 pounds of triethanolamine are added, either at one time or slowly, together with 14 pounds of the pigment chromium oxide green prepared as follows:- In a separate, small container the chromium oxide is made into a paste with part of the triethanolamine, gradual additions of the latter being made until the pigment is thoroughly wetted and the mass has reached a fairly still paste consistency. Then the remainder of the .and formed triethanolamine stearate.
triethanolamine is added. When thoroughly mixed with the rest of the material the' whole mixture is then poured into the stearic acidsoap melt and stirred until the reaction between the triethanolamine and the stearic acid is complete, a matter of two or three minutes. The stirring is theircontinued until substantially all of the stearic acid ,has been reacted upon by the triethanolamine, and triethanolamine stearate is formed and thre is' an even distribution of the color throughout. The mass in the kettle at this time is a molten solution of soaps in one another. The resultant colored mass is now poured into molds, or it may be permitted to cool until a desired temperature and consistency is' :sample 11 20 pounds of stearic acid is melted as in Exl ample 10 in an appropriate kettle and 25 pounds of sodium stearate is slowly added with agitation. The agitation is continued until all of the sodium stearate is in solution. 8.8 pounds of triethanolamine preferably incorporated with l0 pounds of vcarbon black preferably in the same manner as indicated'in Example 101s now added and agitation is continued until all of the triethanolamine has reacted with the stearic acid 7 pounds of paramn wax are now added. The mixture is then molded or extruded into the form of a crayon.
- Example 412 Pounds Stearlc acid 22 Hard soap- 25 Triethanolamine 8.8 Ultramarine blue 13.25
'l'.he stearic acid is melted at a temperature of about 220 F. the soap then added, and the heat maintained, with stirring, until the soap is dissolved. The Atriethanolamine is mixed as in Example 10 with 13.25 lbs. of ultramarine blue and is stirred into the mass with agitation until the triethanolamine is reacted with the stearic acid;
The mixture is then molded or extruded in the form oi' a crayon.
Example 13 28.8 pounds of solid triethanolamine stearate which lhas been previously made by the addition of 8.8.pounds of triethanolamine to 20 pounds of molten stearic acid and permitted to solidify by cooling, is placed in a container and brought to the molten condition by the application of heat. pounds of sodium stearate is now vadded gradually and permittedto dissolve. 'I'he dissolution 'his assisted by agitation and continued heating. -7 pounds of parailln wax are now added and 10 j-Jpounds of carbon black are thoroughly incorl 50 above.
lmlllellofhlnirwsebutothcrwise desirable properties for marking on my panel 'Ihe ceresine is heated to about 20D-210 F.
When `thoroughly melted the blue pigment i's 1 stirred in and the mixture cooled and given a crayon shape. f
Example 15 \l Pounds Cere'sine 35 15 Sulphonated tallow 5 Chromium oxidegreenpigment 24 The binding materialaceresine'and sulphonated tallow, are heated to about 20G-210 F. 20 When thoroughly melted and blended the chromium oxide is added and well stirred in, the massis cooled and shaped.
Example 16 Pounds *5 Paramn wax or melun; point of about 13oc F- 2o Stearlc acid Candelilla wax 10 Spermaceti- 1 Ultramarlne blue 23 The paraiiin wax, stearic acid, candelilla wax and spermaceti are melted and blended together.
mass is cooled and shaped. l 35 Soap-containing hand-size crayons made in accordance with the above examples have an unusualstrength. 'Ihey may be dropped from a height of 4 to 10 feet on hard concrete or wooden floors without causing the crayon to break even 40 when unencased. A similar drop would break a chalk or wax crayon into many small bits.
The crayons and boards described in the specie examples' have the desirable characteristics mentioned. The boards are of opaque or nearly 45 opaque appearance. They have a glazed surface of a non-abrasive character substantially without roughnesses except for possible slight undulations. All of the crayons are unctuous. The soap crayons have an inherent toughness as described 'I'hey do not soften or harden appreciably at temperatures in a range of about F. above or below room temperature and all crayons are tacky when the point is touched on the glazed surface so that they are capable of 55 depositing on the marking surface clearly legible marks of about the same drag as that of ya, soft pencil if applied to ordinary writing paper. All of the crayons may be removed by simple rubbing, without appreciable smearing, with a soft so cotton cloth without leaving a-stain or any substantial residue of the vcrayon on the surface. The expression "pasteboard as used in the appended claims is intended to include chip board, wood ilber board. brown pasteboard and card- 65 board. y l
The panel drawing boardsherein described in accordance with my inventionare substantially water-repellent or water-resistant. They are tough enough not to crack easily. The cellulose 70 foundation boards do not tear easily and at Athe The pigment is added and wen stirred 1n, tne/ same time are' not so hard as to bel brittle. They are reasonably resistant to the action of light,
atmospheric attack and temperature changes.
I claim: 75 1. In combination, a panel drawing board whichis at least partially opaque having a glazed surface of a non-abrasive character substantially without s, except for possible slight undulations, and an unctuous crayon of contrasting coiorfor marking thereon whose composition 5 is of an inherent hardness if employed unencased and in the usual hand crayon size sumcientfor hand marking and which does not soften or hard.- en appreciably at 'temperatures in a range of about 15.,I".` above or below room temperaturalov and is tacky when its marking surface is touchedv on said glazed surfaceso ,that said crayon will deposit on 'said surface clearly legible marks with aboutwthe same drag as that of a soft lead pencil on` writing paper, but may be removed by simple l5 rubbing without appreciable smearing with a soft cloth without leaving a stain or any substantial residue of said crayon on said surface.
2. In combination, a panel drawing board which is at least partially opaque comprising a relatively flat underbody Vand a glazed surface coating thereon of a non-abrasive character substantially without roughnesses, except for possible slight'undulations, and an unctuous crayon of contrasting color for marking thereon whose composition is of an inherent hardness if employed unencased and in the usual hand crayon size sumcient for hand marking and which does# not soften or harden appreciably at temperatures in a range of about 15 F. above or below room 3 temperature, and is tacky whenuits marking surface is touched on said glazed surface, so that said crayon will deposit on said surface clearly legible marks with about the same drag as that of a soft lead pencil onwriting paper, but may be removed by simple rubbing without appreciable smearing with a soft cloth without leaving a stain or any "substantial residue of said crayon on said surface.
3. In combination, a panel drawing board which 40 is at least partially opaque comprising a sub-A stantially flat sheet Vhaving a lacquer coating thereon and providing a glazed surface of a nonabrasive character substantially without rough-` nesses, except for possible slight undulations, and an unctuous crayon of contrasting color for marking thereon whose composition is of an inherent hardness if employed unencased and in the usual hand crayon size sufficient for hand marking and which does not soften or harden appreciably at v temperatures in a range of about 15 F. above or below room temperature, and is tacky when its marking surface is touched on said glazedv surface, so that said crayon will deposit on said sur- 'face clearly legible marks with about the same 65 Voi' saidcrayon on said surface.
4. In combination, a panel ydrawing board which is at least partially opaque comprising a paper-containing vsheet and a cellophane sheet secured upon the face of said mst-mentioned sheet, and providing a glazed surface thereon of a non-abrasive character substantially without roughnesses, except for possibleslight undulations, and an unctuous crayonA of contrasting color for marking thereon whose composition is of an inherent hardness if employed unencased and in the usual hand crayon size sumcient for hand marking and which does not soften or harden appreciably at temperatures in a range of about 15 F. above or below room temperature,
and is tacky/when its marking surface is touched ing color for marking thereon whose composition on said glazed surface, so that said crayon will deposit on said surface clearly legible marks .with
about the same drag as that of a soft lead pencil on writing paper, but may be removed by simple rubbing without appreciable smearing with a soft cloth without leaving a stain or any substantial residue of said crayon on said surface.
5. In combination, a panel drawing board which is at least partially opaque comprising a cementasbestos wallboard coated with'a vinylite resin solution to give a glazed surface of a non-abrasive character substantially without roughnesses, except for possible slight undulations, and an unctuous crayon of contrasting color for marking thereon whose composition -is of an inherent hardness if employed unencasedv and in the usual hand crayon size suicient for hand marking and which do'es not soften or harden appreciably at temperatures in a range of about 15 F. above or belowroom temperature, and is tacky when its marking surface is touched on said glazed surface, so that said crayon will deposit on said surface clearly legible marks with about the same drag as that of a soft lead pencil on writing paper, but may be removed by simple rubbing' without appreciable smearing with a soft cloth without leaving a stain or any substantial residue of having a hardening, lubricating and tacky material therein, substantially free from brittleness and of` a hardness if employed in the usual hand crayon size sufllcient for hand marking but not softening or hardening appreciably at temperatures in a range of about 15F. above or below room temperature, and is tacky when its marking surface is touched on said glazed surface so that said crayon will deposit on said surface clearly legible marks'wlth about the same drag as that of a soft lead pencil on writing paper, but may be removed by simple'rubbing without appreciable smearing with a soft cloth without leaving a stain' or any substantial residue of said crayon on said surface. f
A'1. In combination, a panel drawing board Whichis at least partially opaque having a glazed surface of a non-abrasive character substantially without roughnesses, except for possible slight` undulations, and an unctuous`crayon of contrasting color for marking thereon whose composition is of an inherent hardness if employed unencased and in the usual hand crayon size suiiicient for hand marking` and which does not soften or harden appreciably at temperatures in a range of about 15 F. above or below room temperature, containing a hard soap, a triethanolamine soap and stearic acid having sufficient slipperiness to move lrapidly across the surface in marking, but is tacky when its marking surface is touched on undulations, and an unctuous crayon of contrastis of an inherent hardness if employed unencased land in the usual hand crayon size sumcient for hand marking and which does not soften or hard' en appreciably at temperatures inv a range of about 15 F. above onbelow roomV temperature, containing la hard soap, triethanolamine soap and a wax having siilicient slipperiness to move rapidly across the surface in marking, but is tacky when its marking surface is` touched on said glazed surface and will deposit thereon clearly legible marks with about the same drag as that of a soft lead pencil on writing paper, but may be removed by simple rubbing' without appreciable smearing .with a soft cloth without leaving a stain or any substantial residue of said crayon on said surface.
9. Apanel drawing board for repeated marking and erasure, which is at least partially opaque and having a glazed surface, comprising a relatively at foundation and a glazed coating adhering to the face of said foundation, said foundation and coating being sufficiently vstiil' inherently to permit marking by a crayon thereon, said surface being of a `non-abrasive character substantially without roughnesses except for possible slight undulations, capable of repeated marking and erasing without substantial staining by a crayon which is tacky on said glazed surface. f
10. A panel drawing board for repeated marking and erasure, which is at least partially opaque and having a glazed surface', comprising a relatively fiat cellulose foundation and a glazed coating adhering to the face of said cellulose, said celfiat sheet of cellulose and a glazed coating adhering to the face of said cellulose, said cellulose'and coating being suiliciently sti inherently to permit marking by a crayon thereon, said surface being of a non-abrasive character substantially without roughnesses except for possible slight undulations, capable of repeated marking and erasing without substantial staining by a crayon which is tacky on said glazed surface. 1
12. A panel drawing board for repeated marking and erasure, which is at least partially opaque and having a glazed surface, comprising a sheet of pasteboard and a glazed coating on the face of said pasteboard, said surface being of a nonabrasive character substantially without rough- `nesses except for -possible slight undulations,
capable of repeated marking and erasing without .substantial staining by a crayon which'is tacky cn said glazed surface.
13. A panel for writing, drawing and thelike, having a board containing an organic resin plastic composition of a character to display clearly marks made thereon and of suflcient rigidity to resist scarring by pressurerin marking thereon. 14. A panel for writing, drawing and th'e like,
-having a board containing an organic cellulose` plastic composition of a character to display clearly marks made thereon and' of suiiicient rigidity to resist scarring by pressure in marking thereon.
position of a character to display clearly max-ks made thereon and of sumcient rigidityto resist scarring by pressure ih marking thereon.
17. In combination a panel for writing, drawing and the like, having a board with a glazed surface which has the characteristics of a molded resin,vand an-unctuom crayon of contrasting color forv marking thereon whose composition is of an inherent hardness :if employed unencased and in the usual hand crayon sise suihcient for hand coloring material.
marking and which does not soften or harden appreciably at temperatures in a range of about 15 F. above or below room temperature, and is tacky when its marking surface is touched on said glazed surface, vso that said crayon will deposit on said surface clearly legible marks with about the same drag asthat of a soft-lead pencil on writing paper. but may beremoved by simple rubbing without appreciable smearing vwith a soft cloth without leaving a stain or any substantial residue of said crayon on said surface.
18. In combination a panel for writing, draw;
ing and the like, having a board with a surface which has the characteristics of a molded resin, and an unctuous crayon which comprises the combination of a soap, a fatty acid, ethanolamine and CHARLES BQ