US2317159A - Writing device - Google Patents

Description

Patented Apr. 20, 1943 v r 2,317,159 WRITING nnvion- No Drawing. Application October 13, 1941,

Serial No. 414,865

2 Claims.

The present invention relates to a writing device, and it particularly relates to a writing device such as a pencil or crayon which will give markings or writings visible in the dark. I

Although not specifically limited thereto, the

present invention will be directed to a crayonor pencil which may be used to produce marks, signs or writings upon substantially any kind of a surface and upon boards, walls, etc., which will be visible for long periods of time in the darkness and/or during black-outs.-

It is among the objects of the present invention to provide an inexpensive, readily manufactured, easily utilized pencil or marking device which may be employed by any one accustomed to using a crayon or pencil to indicate or write directions, signs or make marks which will be visible for long periods of time during periods of darkness or during black-outs.

Another object of the present invention is to provide an improved, simple, durable, inexpensive luminous writing composition which may be readily compounded and effectively used for giving luminous markings the luminosity of which will remain for extended. periods of time.

Still further objects and advantages will appear from the more detailed description set forth below, it being understood, however, that this more detailed description is given by way of illustration, since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention.

In accomplishing the above objects, it has been found most satisfactory according to one embodiment of the present invention to provide a combination of a wax or a combination of waxes and resinous materials, together with one or more sulphides, such as zinc, calcium, strontium, barium, magnesium, sodium or rubidium. These sulphide salts may be activated with radio-active salts, such as mesothorium or radium bromide, chloride or sulphate in minute quantities. The luminous sulphide or other phosphorescent material must be uniformly dispersed in the wax or resinous materials, or both.

The waxy material is generally proportioned so that the writing composition may be spread and will adhere in sufiicient thickness to the surface on which the writing, sign or mark is to be made and yet at the same time the wax should not permit undue plasticity or rigidity with changing atmospheric temperatures from summer or tropical temperatures to winter or arctic temperatures.

stand up when utilized.

It has been found that the wax may conveniently be used in amounts ranging from 20% to of the composition with a combination of wax preferably being utilized so as -.to regulate the brittleness, elasticity and tend cncy toward oxidation.

A particularly satisfactory combination is a combination of Japan wax, ozokerite and parafiin, which may be mixed together in equal proportions or in varying proportions from 1 part of one to 2, 3 or 4 parts of the others, to give a composition which does not oxidize or yellow too quickly, which.will be of just the proper elasticity and which will not become too hard or brittle.

For example, where parafiin would be used by itself, there would be a tendency toward undue hardness or brittleness, while Japan-wax would tend to oxidize too quickly and ozokerite would not have the physical strength or body to In the preferred composition from 50 to 200 parts by weight of Japan wax are combined with from 25 to '75 parts of ozokerite and from 50 to 300 parts of paraffin.

In the preferred compositiomthis mixture of waxes is desirably combined with sufiicient petroleum jelly or petrolatum, say, from 25 to 250 parts, to give the desired plasticity and filmforming characteristics.

For example, in one specific example Where it is desired to provide a relatively cheap crayon or pencil for pocket use, about 1 centimeter in diameter, a composition may be made by mixing 50 parts by weight of ozokerite and 225 parts by weight of paraffin, which composition is then mixed with about to parts of Japan wax and then with 125 to 175 parts of petrolatum, with the entire mixture being heated up until a uniform homogeneous molten mixture thereof is formed.

In addition to the waxes above mentioned, vegetable and animal oils waxes and fats, such as carnauba Wax, candelilla wax, myrtle wax, montan wax, cottonseed oil, palm oil, cocoanut oil, laurin, beeswax, Chinese wax, lard, spermaceti, suet, stearic acid, also synthetic waxes and fats may be used to replace part or all of the various wax ingredients of the above mentioned composition.

To make the pencil or the lead self-sustaining, a filler may be utilized. It has been found that a small amount, say, from 5% to 15% colloidal aluminum hydroxide or alumina or potassium or sodium tetrasilicates may be incorporated in the wax composition in addition to the luminous material. Alumina does not decrease the transparency of the waxes and the brightness of the phosphorescent material. The quantity of this sulphide may be varied from 25 to 70% of the entire composition, and desirably the preferred composition consists of 30 to 60% of the sulphide in activated or inactivated form.

To obtain automatic leads for pencils which will have much more body and strength than the wax composition above described, the wax composition may be incorporated, or a minor proportion of the wax compositionmay be replaced, by resinous materials, the. preferred. resinous material being an alkyd resin dissolved in an organic solvent such as butanol; For. ex-

The composition may also be enclosed in or contain supporting inserts of other plastic material such as, for example, graphite, and tubes or rods of ordinary graphite may extend through the material to give it added strength, or the crayon of the present application may actually be inserted Within a cylinder of graphite.

The composition may also be made suificiently plastic so that it can be squeezed out of the tube in the form of a paste, in which case lower melting point waxes and more petrolatum is employed thanv in the proportion given above.

Where leads are made for mechanical or automatic pencils, thecomposition usually contains a high proportion of resin and wax, with the waxes being of high melting point; and the amount of ample, from 60 to 80 parts of the alkyl resin dissolved in from 10 to 30 parts of butanol may be utilized to replace from to 50% of the wax composition, but generally the. resin should always be present in, quantities. less. than 5.0%, and. desirably is best used in quantities. from 20.to. 40%.

Instead of alkyd resins, it is. possible to. use urea-formaldehyde resins, vinylite. resins, phenol.- formaldehyde. resins, acrylic. acid resins, styrene resins or. even modified. natural resins, such as rosin and. shellac, or variousother gums or. resins, These gums or resins may also, be used in emulsified, or saponified form. The proportionsshould always be so regulated that the film. formed. will be substantially in excess of ,6 0 or .of..an inch togive prolongedeffect.

The composition may be enclosed or protected by a transparent or non-transparent. wrapping, such as paper, Celluloid, Cellophane or other suitable materials, to give it .increasedstrength, or in wood. like in ordinary wooden lead pencil, on the resin may be used in. sufficient quantity. to made a substantially rigid self-sustaining stick, as where the resin constitutes .from 10% to 50% of, the composition. and the. wax also constitutesa similar proportion, with the. luminousmaterial constituting the balance of. thecomposition but.

being present. in. quantities. not. less. than 10%.

The. compositionmay, if desired, however, be

made, exclusively of resins or. gums.

petrolatuln. reduced- Gther phosphorescent materials than luminous sulphides may be used. The synthetic carnauba type and bees type waxes may also be employed, such as petroleum or. coal decomposition, prodacts, orby esterification of; stearyl. oleyl; lauryl. myristyl andpalmityl. alcoholswith high molecular weight. fatty acidsv such as, stearic acid, palmitic acid, Qleic; acid,anol;s,o forth.

- I;t.wi11 be understood that many changes could be.v made in. the particular ieaturesof: Writingd evice. as shown, and: many-apparently widely different. embodiments of. this invention couldbe. made without departing from. the scope thereof. It is intended that all matter contained in. the above description shall be interpreted as. illustrative and not in. a limiting sense. I

What. is claimed is:

1. A. luminous plastic writing stick, composed of to parts byweiehtof: Japan w x, 25 to 7:5;parts0f. ozokerite, 50 to, 300 parts, of paraflin and. 25,.to. 250 parts. of petroleum jelly and-asmall;

amount of. a luminous sulphide.

2. A luminous plastic writing stick, composed of 50 parts. by weight of: ozokerite, 220 p rts by weight. of. paraffin. 150, parts by weight of Japan wax andlfill parts. by, Weight; of petroleum and a luminous. sulphide. present in; amountv varying 45. from 251%..11070'71: of the entirecomposition.

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