US1305621A - Leather substitute - Google Patents

Description

rmrrnn srnras PATENT orFioE.

JOHN D. PRINCE, OF sosron, MASSACHUSETTS.

LEATHER SUBSTITUTE.

No Drawing.

To all whom it may concern:

Beit known that I, JOHN D. PRINcE, a citizen of the United States, and resident of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in Leather Substitutes, of which the following is a specification.

This invention relates to a sheet material designed to be used as a substitute for leather, buckskin, chamois, and the like, and

' also as a substitute for rubber in many of its applications. It is particularly directed to the industry of manufacturing boots, shoes and the like, but it is of such a nature as to have a very wide range of usefulness; some other applications which I may mention being floor coverings, upholstery, vehicle tops and covers, waterproof clothing, piston packing, etc.

One of the particular features of advantage of this invention is the fact that it has a permanent fibrous appearance, so that it may, from the point of View of looks, fully satisfy the requirements of a substitute for leather, buckskin, chamois, or other material of the same general nature. In this respect my material is sharply distinguished from rubber compounds, which have been in use, inasmuch as the latter have, at the beginning and throughout their life, a glossy ap pearance as contrasted with a fibrous one.

Again, my material may be used by shoe manufacturers in exactly the same manner as leather is used today, no matter whether it be applied as soles, heels, or uppers. The very same machinery, dies, models and other appliances may be used. It is also susceptible to the same finishing process, including the polishing, coloring, edging and stitch ing, Whether the latter be known as the channeling method, the McKay method, the stitched aloft method, the stitched down method, or any of the other well known methods of securing soles to uppers.

Furthermore, this material is about 20% cheaper than high grade leather, and on grinding tests, it has shown its wearing qualities to be 85% greater than that of the best scoured oak sole leather, and 73% better Specification of Letters Patent.

The material is about 100% more flexible than leather of corresponding thickness; it is waterproof, although it absorbs a suflicient amount of moisture to make it more desirable than rubber, particularly when applied to the manufacture of shoes or waterproof clothing, for the reason that it does not produce the so-called sweating effect. It will not slip on wet pavements, nor will it adhere to clothing. It is much more resilient than leather, so that it is applicable to use in place of the so-called rubher heels, for the purpose of avoiding jars and shocks. It is heat proof and cold proof.

With this brief outline of the general nature and characteristics of the material, I will proceed to describe the manner in which it is made.

Broadly considered, the material is composed of a fiber which has been ground so Patented June 3, 1919. Application filed July 22, 1916. Serial N 0. 110,698.

as to be broken into short lengths, and 'rubber compounded with sulfur; the whole being suitably vulcanized into the desired sheet form and thickness. Other ingredients which are added in compounding the material serve to enhance its valuable qualiies; and, in the best form of the invention now known to me, the same is composed of cotton fiber, selected sheet Ceylon rubber, pure rubber gum, known as concho, reclaimed rubber or shoddy, pontianak, pulverized magnesia, red oxid of iron, and sulfur.

I find cotton-fiber to be the most desirable of all, owing to its strength and availability, but, other vegetable fibers, such, for instance, as hemp, flax, jute, sisal, wood fiber, straw or grasses, may be employed.

In carrying out the invention, the cotton, as it is baled, is provided'and subjected to a grinding process; a. 9., between heavy rollers in a machine commonly known as a rag mill, which is designed for grinding fibrous material. The cotton is preferably ground in mass so that the grinding process shortens instead of crushing the fiber, the effect being a tearing apart as distinguished from a flat pressure. The cotton is ground to lengths of approximately 1/100 of an inch and is then ready for use in compounding my material. Thus, when I say in the claims short length fiber, I refer to fibers of not more than about one to ten one hundredths of an inch long.

To a batch aggregating approximately 20 pounds, the ingredients mentioned are mixed in substantially the following proportions:

4.; pounds of cotton fiber, in its ground condition;

L pounds of selected sheet Ceylon rubber- 1% pounds of pure C-oncho rubber gum;

9 pounds of reclaimed rubber shoddy;

1 pound of pontianak;

pound of pulverized magnesia;

g; pound red oxid of iron; and

1% pounds sulfur.

These ingredients are compounded and thoroughly milled between. heated rollers into a mass, as is customary in compounding rubber, which is well understood in the art.

I prefer to use the selected sheet Ceylon rubber because it is very strong, clean and pure. However, other kinds of rubber can be used in its place, such, for instance, as up-river Para.

The Concho rubber is selected because of its great adhesiveness and elasticity. Furthermore, it is a good, pure rubber and blends well with the other ingredients incorporated. But, in this case also, other rubber gums can be used, such, for instance,-

as Manocoba.

The pontianak, which is a byproduct of a resin, is particularly desirable owing to .its adhesive properties, but other resins may be used in its place.

The reclaimed rubber, which is commonly referred toas shoddy, is a regular ingredient of rubber compounds, and is desirable for the purpose of cheapening the product.

The pulverized magnesia is, as is well understood, a drier, and is generally used in rubber mills. It has a suificient drying effect, is light in weight and a good filler. In place of it some such material as chalk flour could be used, if desired.

The red oxid of iron 18 used for the purpose of a coloring agent, but it could be substituted by any other well known pigment material, such as lamp black, black carbon, chrome yellow, yellow ochre, Indian red, etc.

The sulfur is, as will be well understood,-

for the purpose of vulcanization.

" After the mixture has been compounded and milled as described, it may be vulcan ized in any of the ordinary ways, such for instance, as in a flat sur ace press, or on rolls wrapped with wet cloth. A very convenient way is to vulcanize it in a press, the plates of which are blocked apart a sufiicient distance to give the finished sheet material the desired thickness. The vulcanization is preferably carried out at a temperature equivalent to 35 pounds steam pressure, and for a time period of 25 minutes. This quick vulcanization, at a comparatively low temperature, is very desirable from the point of view of economy of time, fuel and labor, and it also is advantageous as it minimizes the tendency of the heat of vulcanization to injure the natural oily or waxy material in the cotton fiber. The manner of vulcanizing will be well understood to any one skilled in the art, Without further description.

After vulcanization, either one or both surfaces of the material may be bufied to remove any glossy appearance resulting from the action of the platesin the vulcanizer, so as to provide a natural, fibrous appearance. This buffing may be accomplished by any of the ordinary methods commonly employed in rubber manufactories, and is well understood in theart.

Instead of simply vulcanizing the material into sheets, it may be associated with cloth, such, for instance, as duck or sheeting, by calendering, in a well known manner, the composition onto one or both surfaces of the cloth. The cloth thus calendered with the material, may be subjected to heat for the purpose of vulcanization, after which it may be applied to such uses as Waterproof clothing, uppers for shoes, upholstering or other cases where a very flexible leather or rubber sheet is required;

\Vithout setting forth at greater length the characteristics and advantages of my invention, I may repeat that two of its greatest features of value lie in the fact that it may be employed by the manufacturer in exactly the same way that leather isused, and that it has, at the beginning, and during its whole life, a fibrous leathery appearance.

In conclusion, it will be understood that 110 various changes may be made in the ingredients and proportions specified; and in the method of treating, compounding and vulcanizing the various substances, without departing from the spirit and scope of my 115 invention; hence I do not intend to be limited to details hereinbefore described except as they may be specifically included in the claims.

What I claim is 1. A permanently fibrous material designed as a substitute for leather and the like, comprising short length fiber, a pure, clean rubber. and a strong and adhesive rub her, the same being compounded with sulfur a resin, and a drying agent, the Whole being compounded with sulfur and vulcanized.

3. A permanently fibrous material designed as a substitute for leather and the like, comprising a short length fiber, a pure, clean rubber, a strong and adhesive rubber shoddy, a resin, a drying agent, anda pigment, the same being compounded with sulfur and vulcanized. v

4. A permanently fibrous material designed as a substitute for leather and the like, comprising short length fiber, selected sheet Ceylon rubber, gum Concho, shoddy,