US2280988A - Pencil composition - Google Patents

Description

Patented Apr. 28, 1942 UNITED STATES PATENT OFFICE No Drawing. Application November 14, 1939,

Serial N0. 304,388

4 Claims.

invention pertains to compositions for use in pencils and the like, such pencils being capable of marking sheets of cellulose nitrate, cellulose, acetate, etc.,,such compositions being particularly well adapted for use in drawing upon such sheets in colors whereby the sheets may be suitably superimposed and then photographed in colors in the production of photoplays, animated cartoons, etc.

Although the compositions embraced by the present invention may be used in the manufacture of various pencils and crayons capable of being employed in many diverse manners, the description appearing hereafter will be particularly directed toward compositions for use in the animated cartoon industry. .In producing animated cartoons, particularly when the iinal films are to be in substantially natural color, the drawings originally made by the animators or artists are traced. upon sheets of Celluloid and the outlines then filled in with suitable opaque paints. These sheets of Celluloid are called "cells and the cells are placed in superimposed relation, each cell containing one or more elements or characters appearing in the final or.

completed scene. The cells maybe placed in juxtaposition or may be spaced from each other but at all events the cells are photographed simultaneously, the opaque portions of foreground cells blocking out and covering portions of cells which are more distant from the camera.

In a co-pending application reference has been made to a technique of creating a depth of tone,

which technique includes the steps of applying a stipple-or. shade or modifying tone to certain of the objects or characters depicted on the cells. The present invention is directed to pencil compositions which not only permit the artist to work directly on the cells but in addition permit the artist to produce pastel effects, textures, stlpples and stains capable of creating the depth or roundness referred to in the co-pending application Serial No. 305,480 (Patent No. 2,254,462).

It is to be remembered that the cells are made from hard-surfaced materials such as organic plastics or resins (polymers of acrylic acid and vinyl acetate are examples) or comprise a derivative of cellulose, such as for example, cellulose parent and provided with a glossy, substantially impervious surface having every high surface "tension particularly in comparison with normal ingredients, paints and the like. Hard wax pencils are incapable of leaving a uniform mark on these cells because'of the peculiar characteristics of the surface of the cells. The compositions ofthe present invention, however, will produce smooth, uniform lines or if desired, the

composition may be caused to result in a capable of reacting with the cellsurface so as to permit the excess material to be wiped off the cell and still leave a residual color or tone whereby translucent and semi-transparent shades or tone elements may be formed on the cell for the purpose of modifying underlying objects or colors. These stain or blend effects are of special utility when it is desired to impart roundness or depth to objects delineated upon the cells.

The compositions of .the present invention comprise a base and suitable dyes and pigments. The base consists of waxes, binders and solvents and may also include plasticizing ingredients. The proportions of the ingredients employed may vary somewhat with the use to which the final composition is to be put and the effect desired.

An object of the present invention, therefore, is to disclose and provide a new medium with which artists and animators may express themselves on cellulose films, such as cellulose nitrate or cellulose acetate or on other transparencies.

Another object is to disclose and provide a novel composition of matter adapted for use in sketching or painting on transparent glossy materials such as sheets of cellulose derivatives or transparent plastics.

An object of the invention is to provide a waxy composition adapted for use in pencils, said composition containing solvents adapted to react with the surface of cellulose derivatives to which it is applied and to leave a dye or color tone thereon.

A further object is to disclose ingredients and compositions which result in a stable, effective art medium for use on cellulose derivatives, etc.

acteristics may be produced.

These and other objects, uses, advantages and modifications of the invention will become apnitrate or cellulose acetate. The cells are .transparent to those skilled in the art from the following detailed description of certain preferred ingredients and examples.

. In making up the pencil compositions, various, 7

insect, vegetable and semi-mineral waxes may be used. The most commonly employed waxes are beeswax, candelilla, camauba, Japan :and montan wax. Stearinis also employed.

None of these waxes alone is capable of being used, however, since it will not adhere to a cell and does not have sufficient strength to retain its shape when in use. For example, beeswax, although capable of leaving a mark'on a cell surface, will not make a continuous mark and is too flaky. Carnauba wax, although appreciably harder than beeswax, is too brittle and does not adhere well to the cell surface. I

'In accordance with the present invention it has been discovered that the waxes can be strengthened and their adherence to a cell surface markedly increased by including binders in the composition. The term binder as used herein refers to substances which are compatible with waxes and which have a tendency to hold the wax structure together. For example,ethyl cellulose is a relatively soft'but tough substance soluble tosome extent in stearic acid. Phenolic resins of various types may be used instead of ethyl cellulose. The binders not only'assist in imparting-strength to the compositions but have a tendency to raise the melting point thereof. Since many of the waxes employed are coarsely crystalline or have a tendency to cool into av coarsely crystalline structure, it is desirable to employ in the final compositiona substance capable of inhibiting largecrystal growth, thereby assuring the production of a pencil of more uniform and homogeneous character.

carnauba, beeswax and montan wax, contain saponifiable constituents in various proportions and these constituents may be saponified or converted into soaps, in part at least, by the addition of a suitable mild base or alkali to the comas stearin or fatty acids present in the waxes) Many of the a waxes, such as for example, Japan wax, candelilla,

position. Instead of employing ordinary caustic a milder base such as triethanolamine or other similar amines.

When the final composition is to be used in a pencil capable of leaving a stain or dye on the cell surface, the pencil should contain a reagent capable of affecting the surface of the cell. Although many reagents or solvents answering this description are available (ketones, ar-yl halides, acetals, esters containing less than ten carbon atoms, etc.), I have found acetates such'as carbitol acetate, phenol acetate, butyl acetate and ethyl acetate to be more desirable. Most of the solvents capable of rapidly reacting with the cell surface are relatively volatile and therefore the pencil compositions change in their properties and effectiveness, with age and storage. to stabilize the pencils, I have found it desirable to employ plasticizers, particularly those having some solvent effect or those which are capable of combining with the more volatile solvents with out destroying the solvent effect thereof. For example, it has been found that dibutyl phthalate is an efiective plasticizer for use incompositions of the character claimed herein since it is miscible with carbitol acetate and the like and instead of decreasing the solvent action of the acetate,

In order or rods, either by casting or by extruding the stil .ethanolamine, to the mixture during compoundfrom the followingingredie'nts'in; theproportions given:

General Preferred range range Percent Fervent Hard waxes. 45 to 65 5t0 25 65 to 4 to 15 v 4 to 20 Plasticizers 0 to 15 5 to 15 In the e ent triethanolamine is used in the composition the products of reaction between the triethanolamine and any added fatty acid (such may be considered to act not only as a means for inhibiting large crystal growth but also as a plasticizer. When such soap reaction products are presentand are considered to act as plasticizers, then the total amount of plasticizers present may amount'to as much as 25% to even 30%.

i As has been stated before, the binders preferably comprise substances such as ethyl cellulose, resins and vegetable gums. In addition, highly polymerized oil products, varnish gums, thickened wood oil, etc., may be used.

It is to be understood that in addition to the above, suitabledyes (preferably. oil soluble) either alone or in conjunctionwith pigments or pigments alone may be added to the base composition given for the purpose of imparting to the base composition a desired shade or tone. The percentage of dye and/or pigment by weight of the base may vary from about 0.5% to as high as depending entirely upon the tinctorial power of the dye or pigment employed and the shade or tone desired. Ordinarily, pigments of low specific gravity are to be preferred to pigments of high specific gravity since the latter do not appear to produce as homogeneous compositions and have a tendency to'impair the ability of the composition to delineate a smooth, continuous, sharp line upon the surface of the cell.

The mode of compounding the ingredients comprises melting desired waxes in desired proportions and adding thereto with accompanying agitation the remaining ingredients of the mixture. Ordinarily the ingredients are maintained in moltencondition for a period of from 15 minutes to several hours whereupon the pig ments or dyes are added and the agitation continued while a temperature sufiicient to produce a mobilemass is maintained. In the eventthe composition is to contain relatively volatile solvents, the solvents are added at as low a temperature of the mass as it is possible to maintain and to the warm wax base.

mitted to cool and is then formed into cylinder plastic mass through suitable dies. The-result? ing cylinders, or formed masses may be wrapped or encased in paper, wood or any 'otherisuitable' composition.

' from about 4% to 25% by weight of solvent capahle of reacting with the surface of an object Specific examples of compositions made in accordance with this invention will now be given:

Percent Percent Percent Montan wax 20 0 Candclilla. 20 30 i8 (amauba 22 2a 0 .lapan., 0 0 18 Stearic acid l0 9 37 'lricthanolamine. 5 0 Phenolic resin. 5 5 0 Ethyl cellulose. 0 1 l1 Gum damar 0 5 0 Dibutyl phthalate. 13 ll 5 (arbitol acetate .7 5 5 ll It is to be remembered that suitable dyes, pigments or mixtures thereof are added to each of the bases. Oil-soluble dyes are preferably used.

It is further to be remembered that in the event it is desired that the pencil apply or form a smooth mark upon the surface to be treated,

the quantity of binder be reduced somewhat or made of cellulose derivatives up to about 30% by weight of plasticizing agents, and a binder. 5

lulose or the like. Furthermore, when it is de- 1 sired to produce a smooth pencil, larger quantities of so-called softer waxes are employed and smaller proportions of harder waxes. By soft waxes, reference is made to waxes such as beeswax, stearin, etc.

I claim:

1. A pencil composition adapted to form a difficulty removable stain on the surface of objects made of cellulose derivatives, which comprises: a base containing 50% to 80% by weight of waxes,

2. A pencil composition adapted to form a difficulty removable stain on the surface of objects made of cellulose derivatives and organic plastics, which comprises: a base containing to by weight of waxes, from about 4% to 25% by weight of solventcapable of reacting with the surface of an object made of cellulose derivatives and organic plastics up to about 30% by weight of plasticizing agents, a part at least of said plasticizing agents comprising products of reaction between an organic base and fatty acids, a binder, and an oil-soluble dye.

3. A pencil composition adapted to forma difficulty removable stain on the surface of objects made of cellulose derivatives and organic plastics, which comprises:- a base containing 50% to 80% by weight of waxes, from about 4% to 25% by weight of solvent capable of reacting with the surface of an object made of cellulose derivatives and organic plastics, up to about 30% by weight of plasticizing agents, a part at least of said plasticizing agents comprising products of reaction between an organic base and fatty acids, 2% to 15% by weight of a binder, and ancilsoluble dye.

4. A pencil composition adapted to form a difflculty removable stain on the surface of objects made of cellulose derivatives and organic plastics which comprises: a base containing 50% to by weight of waxes, up to about 30% by weight of plasticizing agents, a bindena solvent capable of reacting with the surface of an object made of cellulose derivatives and organic plastics, and an