US2852398A - Base for non-solid writing media - Google Patents

Description

United States Patent BASE FOR NON-SOLID WRITING MEDIA Gerald A. Goessling, Richmond Heights, M0.

N0 Drawing. Application May 10, 1954 Serial No. 428,787

3 Claims. (Cl. 106-31) The present invention relates generally to writing media, and more particularly to a novel base or vehicle for non-solid writing media which are particularly adapted for use in rotating-ball type Writing instruments, and Whlch are controllable as to their physical characteristics to provide an erasable non-smudging writing medium, a permanent non-smudging medium, or a non-smudging writing medium having erasability and penetrating characteristics anywhere therebetween.

Briefly, the invention resides in a writing media base for pigments or dyes (or both), comprising an asphaltum or tarry mass, and predetermined amounts'of a relatively light oil to control the erasability and penetrability of the resultant writing medium.

During recent years, much effort has been directed toward developing inks for use in rotating-ball type instruments which are permanent, which will not transfer or smudge, and which will write on wet or oil smudged paper. Efforts have also been made to develop inks which produced marks which simulate the marks produced by conventional lead pencils, and which are readily erasable. In short, the requirements as to erasability, permanency, and the like, vary with the particular use required of the ink or writing medium. Although many inks and other types of non-solid writing media have been developed which satisfy some of these requirements, each has to be tailormade to meet a particular requirement and is completely different in chemical composition and physical make-up from one produced to satisfy different requirements. Also, most of the known inks have relatively short shelf life and tend to leak from the writing instrument when it is subjected to heat.

It is an object of the present invention, therefore, to provide a novel base or vehicle for non-solid writing media which can be used with dyes or pigments, or both, and which can be controlled with respect to its physical characteristics to produce a writing medium which will not smudge or transfer and which will be substantially permanent, or to produce a readily erasable non-smudging writing medium, or to produce a writing medium having erasability or permanency characteristics anywhere therebetween. More particularly it is an object to provide such a base or vehicle which can be used with various types of coloring matter and which can be readily controlled as to its physical composition during the manufacture of the writing medium, to produce a writing me dium which will quickly penetrate into the fibers of the paper so as to be permanent and which will not transfer or smudge, or to produce a writing medium which will have very little penetration into the paper so as to lie on the surface thereof and be readily erasable Another object is to provide a base for writing media which will write on practically any type of paper without globbing or skipping and which will not be ad- .versely affected by changes in paper surface characteristics, such as a moist surface or a slick or oil smudged surface. More particularly, it is an object to provide a base 2 for writing media for use in rotating-ball type writing instruments which will write on moist or slick or oil smudged paper without transferring and without spreading.

Another object is to provide a base for writing media which remain within the writing instrument until the latter is moved over the paper or the like, which do not bleed or leak from the instrument, and which do not cling to the exposed point of the writing instrument when it is not in use.

Another object is to provide a base for writing media which do not harden or dry out on exposure to the air as when on the point of a writing instrument, and which have long shelf life.

Further objects and advantages will be readily apparent from the following detailed description.

In order to perform satisfactorily in a rotating-ball type writing instrument, the resultant writing medium must have sufficient body and cohesive strength to remain within the writing unit until it is rolled onto the writing surface. On the other hand, it cannot be too viscous or it will not flow freely through the writing instrument.

Furthermore, it should have sufficient cohesive strength with respect to itself (surface tension) whereby it will not crawl, slip or leak from around the ball or from the upper end of the writing unit, but will work down toward the ball as the writing medium is consumed.

The cohesion or film strength must also be sutficient to cause the medium to flow or be pulled in a uniform unbroken film from the capillary tube, around the ball and onto the writing paper.

The Writing medium must also have sufficient adhesive strength or afiinity for the ball to cling to it and be pulled from between the ball and its seat, and onto the paper. However, its affinity for the writing paper must be greater than its affinity for the ball so that it will be readily transferred from the ball onto the paper and not pile-up on the peripheral edge of the ball seat.

Also, it is desirable for the medium to have more cohesive strength with respect to itself than adhesive strength with respect to the surface of the ball, whereby it will contract or draw back into the space between the ball and its seat, and provide a clean point.

I have developed a base or vehicle for producing nonsolid writing media which have all of the foregoing desirable characteristics. This base can be used with either oil-soluble dyes, colored pigments, or combinations of dyes and pigments, and can be controlled by changing the relative proportions of the principal ingredients whereby the resultant writing medium will lie on the surface of the paper and be readily erasable, or which can be made to penetrate into the fibers of paper so as to be permanent.

The desired base or vehicle which has been developed has the general physical characteristic which can best be described as viscid or tacky. One .method of producing this so-called base or vehicle is to dissolve a tarry petroleum or bituminous material such as asphalt or tar in'a petroleum thinner'or light mineral oil and a solvent such as VMP (varnish makers and printers base) naphtha. After the asphalt or tar is dissolved, the naphtha is evaporated, as with heat, leaving the asphalt or tar dissolved vehicle) is in the nature of 4 to 1, i. e., when the asphaltic' content is about of the starting base. The dissolved Consequently, best results are ob- 3 asphalt comprising about 16% to 32% by volume of the resultant writing composition as pointed out in my co pending application Serial No. 399,221, filed December 21, 1953.

Satisfactory results are also obtained by using as the starting base, petroleum products distributed by various oil companies and which are basically a distillate residue and oil. For example, Cities Service Oil Company markets such a product as Cisco No. 5, -No. SZ, or the like, depending upon the amount of oil mixed 'with the distillate residue. Cisco No. 5 is a residual petroleum asphaltic material which has an approximate dropping point (ASTM degrees Fahrenheit) 143,-an unworked-cone penetration at 77 F. of approximately 245, and a viscosity of approximately 5,000 seconds SUS at 210 F. Cisco No. 5Z'is similar to No. 5 except that it is diluted with trichloroethyleneto reduce its viscosity.

The resultant base is produced by adding to the aforementioned starting base, a predetermined amount of a highly refined oil, which controls the penetration and erasibility characteristics of the resultant writing medium.

The oil is preferably a mineral oil of the non-detergent type so as not to cause the resultant writing medium to transfer or spread when in contact with moisture, or even when used on wet paper.

Another disadvantage of using an oil which contains detergents, is that the detergents may cause a caking or drying out of the resultant writing medium and adversely affect its shelf life. This is especially true when the coloring matter is an oil-soluble dye, as will be discussed more fully hereinafter.

A preferred oil is Rocket F oil, a highly refined parafiin base, non-detergent type mineral oil used in the printing industry and which can be obtained from Sinclair Refining Company, which is a subsidiary of Sinclair Oil Corporation. It is advisable to use high grade, highly refined oils primarily because they are produced under mfire strict controls and are more uniform than ordinary 01s.

A resultant base or vehicle which will produce a writing medium which does not penetrate into the fibers of the paper, relatively speaking, and which is readily-erasable, is produced, for example, by using about 90% to 95%, by volume, Cities Service Cisco No. SZ, and about 5% to by volume, of Rocket F oil.

On the other hand, if it is desired to produce a writing medium which penetrates rapidly into the fibers of the paper, relatively speaking, and which does not smudge or transfer, more of the Rocket F oil is used, c. g. about 30% oil and about 70%-Cisco No. 5Z.

The amount and weight of oil which is used is also dependent upon the type of materials used in the manufacture of the capillary tube and the ball point, and also upon the staking space between the ball and its seat.

The necessary coloring matter to produce the desired color, is then added to the resultant base or vehicle in order to complete the writing medium. The coloring matter can be in the form of a pigment, an oil-soluble dye, or a combination of the two. In order to prevent the resultant writing medium from smudging or transferring, the coloring matter should. be non-soluble with respect to water, and furthermore, the vehicle itself should be non-soluble, and the combination of the vehicle and the coloring matter should be non-soluble.

To provide a writing medium which produces marks which simulate the marks produced by conventional pencil leads and which are readily erased in like manner, a colloidal dispersion of graphite and/ or carbon particles in a light oil (SAE) having a paraflin base is used. All of the particles are substantially less than 7 microns in size and preferably no more than about 3 to 4 microns.

When graphite particles are used, the best results are ob-.

tained when the particle content is between about 10% to by weight of the resultant writing medium and preferably between about 15% to 17%. To obtain the 4 maximum concentration of graphite in the preferred final weight range (15% to 17%) above pointed out, a dispersion of about 30% by weight of graphite particles in oil has been used. The colloidal dispersion is combined with the aforementioned erasable base in the proportions of about 20% to 40% by volume base to about 60% to by volume graphite in oil. In like manner, coloring pigment such as organic toners, e. g. barium lithol, monastral blue, and the like, can be used to produce writing media of various colors, and which are also readily erasable. Erasable non-solid Writing media of this type are fully described in my copending application Serial No. 399,221, filed December 21, 1953.

Furthermore, to produce various colors, one can use oil-soluble dyes which are non-soluble with respect to Water and which are dissolved in along chain fatty acid such as oleic acid, in the ratio of about 1020% solids and about 80-90% carrier (the fatty acid, in effect, taking the place of the mineral oil as when colloidal graphite is used), such as for example, Aviation Blue (Color Index No. 2182) or Oil Soluble Black (Color Index No. '864) of Calc'o ChemicalCo, or Amaplast Red B (Color Index No. 258), Amaplast Green BB (Color Index No. 1078), or Amaplast Blue RB (Color Index No. 1073) of American Aniline'Products, Inc., or Jet Oil Black (Color Index No. 864) or Oil Blue (Color Index No. 2182) of General Dyestuif Corporation, or Jet Oil Black or Oil Blue 2182 of General Dyestutt' Corporation, 435 Hudson Street, New York 14, N. Y., a division of General Aniline and Film Corporation, 230 Park Avenue, New York 17, N. Y., either alone or with pigments, and, by using varying amounts of Rocket F oil,-colored writing media 'canbe produced which either lie on the surface'and-are readily erasable, or which penetrate into the fibers of the paper so as to be permanent, and which do not smudge or transfer.

While the graphite particle composition mentioned above will produce a black marking and the colored pigment and/or oil soluble dye composition may be used to produce colored markings, the amount of the highly refined oil put into the composition will determine whether the writing composition Will penetrate the paper to which his applied and, therefore, not be erasable, or will not penetrate the paper and will be erasable therefrom.

Naturally, when coloring matter and the oil in which it is suspended or dissolved are added to the aforementioned resultant base or vehicle, this oilmust be considered in determining the total amount of oil which should be used in the resultant medium, depending upon whether it is desired to produce an erasable medium or apenetrating medium.

Furthermore, it will be readily apparent that the type of paper on which the writing medium is used will, to some degree, affect the erasability and penetration of the writing medium. Thus, a resultant writing medium is more apt topenetrate the fibers of a soft-finish paper such as newspaper, than a hard-finish paper having a heavy starch coating.

Thus, it is apparent that there has been provided a re sultant base or vehicle for non-solid writingmedia, which fulfils all of the objects and advantages sought therefor.

By beginning with the aforementioned starting base of dissolved asphaltum or tar and by adding varying amounts of a light oil thereto, writing media can be produced which do not smudge or transfer, and which either lie on the surface of the paper and are readily erasable,

or which quickly penetrate into the fibers of the paper so as to be permanent.

Also, the base can be used with colloidal pigments, with oil-soluble dyes, or a combination of the two, to produce various colors or a black which simulates the marks produced by conventional pencil leads.

. In addition, the resultant writing media which are produced following the teachings of the present invention, can be used to Write on wet and oil smudged surfaces and will not spread or smear.

and said tar-like Furthermore, the physical characteristics of the media do not change on exposure to air, whereby the instrument is always ready to write and does not require any priming movement, and has long shelf life.

Consequently, there has been produced what is, or what closely approaches, a universal base for non-solid writing media having variable erasibility and penetrating characteristics, and which do not smudge or transfer.

It is to be understood that the foregoing descriptions have been given only by way of illustration and example and that changes and alterations in the present disclosure, which will be readily apparent to one skilled in the art, are contemplated as within the scope of the present invention, which is limited only by the claims which follow.

What is claimed is:

l. A writing composition which simulates the markings of a conventional pencil lead consisting essentially of a stable colloidal dispersion of graphite particles in a light petroleum oil with substantially all of the graphite particles being less than 7 microns in size as the pigment and said graphite particles being from 10% to 25% by weight of the writing composition, a carrier comprising a tar-like substance selected from the group consisting of tar derived from petroleum and bituminous distillate residue and asphalt dissolved in a petroleum thinner and oil, said colloidal dispersion being from 60% to 80% by volume of the writing composition and said carrier being from 20% to 40% by volume of said writing composition substance being from about 16% to 32% by volume of said writing composition, and adding to said composition from about 5% to 30% by volume of a refined paraffin base non-detergent type mineral'oil whereby the writing composition can be controlled between one which remains substantially on the surface and is relatively erasable and one which penetrates the surface and is relatively unerasable.

2. The writing composition as set forth in claim 1 wherein about 5% to 10% by volume of the refined paraffin base oil is added to the said composition whereby the writing composition will remain substantially on the surface and be erasable.

3. The writing composition as set forth in claim 1 wherein about 30% by volume of the refined paraffin base oil is added to the writing composition whereby the writing composition will penetrate the surface to which it is applied and will be unerasable therefrom.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain of 1881

Claims (1)

1. A WRITING COMPOSITION WHICH SIMULATES THE MARKINGS OF A CONVENTIONAL PENCIL LEAD CONSISTING ESSENTIALLY OF A STABLE COLLOIDAL DISPERSION OF GRAPHITE PARTICLES IN A LIGHT PETROLEUM OIL WITH SUBSTANTIALLY ALL OF THE GRAPHITE PARTICLES BEING LESS THAN 7 MICRONS IN SIZE AS THE PIGMENT AND SAID GRAPHITE PARTICLES BEING FROM 10% TO 25% BY WEIGHT OF THE WRITING COMPOSITION, A CARRIER COMPRISING A TAR-LIKE SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF TAR DERIVED FROM PETROLEUM AND BITUMINUOUS DISTILLATE RESIDUE AND ASPHALT DISSOLVED IN A PETROLEUM THINNER AND OIL, SAID COLLOIDAL DISPERSION BEING FROM 60% TO 80% BY VOLUME OF THE WRITING COMPOSITION AND SAID CARRIER BEING FROM 20% TO 40% BY VOLUME OF SAID WRITING COMPOSITION TO AND SAID TAR-LIKE SUBSTANCE BEING FROM ABOUT 16% TO 32% BY VOLUME OF SAID WRITING COMPOSITION, AND ADDING TO SAID COMPOSITION FROM ABOUT 5% TO 30% BY VOLUME OF A REFINED PARAFFIN BASE NON-DETERGENT TYPE MINERAL OIL WHEREBY THE WRITING COMPOSITION CAN BE CONTROLLED BETWEEN ONE WHICH REMAINS SUBSTANTIALLY ON THE SURFACE AND IS RELATIVELY ERASABLE AND ONE WHICH PENETRATES THE SURFACE AND IS RELATIVELY UNERASABLE