US1790796A - Chusetts - Google Patents

Description

Patented Feb. 3, 1931 UNITED STATES 1 PATENT OFFlCE ALBERT :t. CLAPP, or Dramas, MASSACHUSETTS, 'ASSIGNOR 'ro BEoxwI'rn MANU- rac'runnve COMPANY, or BOSTON, MASSACHUSETTS, A oonromrron or MASSA- CHUSETTS BOX TOE Ho Drawing. Original application filed October 31, 1922, Serial No. 598,214. Divided and application filed September 27, 1924, Serial No. 740,414. Again divided and this application filed March 10, 1827.

Serial No. 174,424.

This invention has for its object to produce a shoe stiffener or sheet material from which such stiifeners may be produced.

Heretofore it has been customary in the manufacture of shoe stifi'eners such as box toes to form a sheet of fibrous materlal, usually cotton'and wool felt or like open porous material, and then to saturate or impregnate the sheet with a molten mass of a stiffening agent in the nature of hydrocarbons, which when cold is hard and friable but which when softened by a relatively moderate degree of heat permits the sheet or blank cut therefrom to become limp and flexible, so that the box-toe blank may be molded about the end of the last in pulling over or lasting the shoe. Various stiffening agents have been employed for this purpose, such as resins,

gums, asphalts and hydrocarbons of the nature of Montan wax.

More particularly, the object of the present invention is to produce box toes or the sheets from which the box-toe blanks may be cut,

by incorporating the stiffening agent with the pulp during the manufacture of the sheet in a paper machine so as to render unnecessary the step of separately impregnating the already formed sheet of fibrous material. It.

is necessary that the stiffening agentbr agents should be thoroughly distributed throughout the sheet, that they should be of such nature that the box toe when molded is resilient and stiff, that they may be softened so as to render the sheet limp and flexible when heated to a relatively low temperature, and that they will set quickly when permitted to cool. One of the prime requisites of the sheet is that it must not part or tear easily when the stiffening agent is in a soft plastic condition, and that it may be stretched to some extent and pulled about the toe end of the last without being weakened or torn so as to conform to .the shape of the lastwithout injury.

The present invention consists of a box-toe blank, the sheet from which it is cut and a method of producing the same which will provide a box toe having the optimumcharacteristics which 'I have hereinbefore feferred to.

In initially preparing the sheet, I employ a furnish, including long fibers such as long rope fibers or flax fibers, and even in some cases may utilize long cotton fibers. In addition to these fibers, however, I also employ short fibers, preferably of the character of wood pulp used in the manufacture of paper,this for the reason that a sheet formed only of long fiber is too open andporous and requires some shorter fiber in order to secure the necessary felting in the formation of the sheet on the paper, machine. Inasmuch as an object which I desireto achieve is to secure a maximum quantity of stifl'ening agent in the sheet, it is necessary that the fibrous body of which the sheet is formed should be of such character that it. will form properly in a web and yet be sufliciently open to permit from waste kraft paper or the like. Of course, I

in lieu of wood pulp,. one might employ rags or other raw material which provides relatively short fibers, which, when mixed with long fibers, will furnish a sheet having the desired characteristics.

As the thermoplastic stiffening agent I may utilize any gums or bituminous materials such as rosin, asphalt, Montan wax, copal or the like, which will give to the box toe the necessary stiffness and resiliency, and which will softenat a relatively low degree of heat and set quickly when cooled. Normally adhesive bituminous materials may likewise be utilized for furnishing the stiffening agents, provided they may be diluted with water and be thoroughly incorporated with the other elements or ingredients of the furnish in the beater stock.

As an example, one may proceed as follows: 8 parts by weight of long fibers such as rope, flax or cotton fibers and 8 parts by weight of sulphate pulp or equivalent short fibrous material may be placed in the beater with a large amount of water, much more than is ordinarily necessary for beating the stock. The beating engine is started in operation but the knives are carefully adjusted so as not to cut the fibers but merely to brush them and secure a thorough, physically homogeneous mixture. The stock should be thinned with 5 water as this permits the rapid. admixture of the ingredients.

longer time, one might secure the same results with a thicker stock or one having less water. By having a very thin stock, it is possible to. secure the desired physical homogeneity in. the course of to minutes. After the beater contents have been brushed as described, the thermoplastic stifl'ening agents may now be added. In the example herein 15 given, I employ parts byweight of rosin, 25 parts by weight of gilsonite and 5 parts by weight of Montan wax, all pulverized to about mesh. These ingredients are introduced into the beater, together with about 30 20 parts of asphalt emulsified or dispersed in water. This emulsion or dispersion preferably consists of normally adhesive asphalt emulsified or dispersed in water with a colloidal' clay emulsifying agent, the asphalt 25 constituting the disperse phase of the emulsion. The amount of the emulsion added to the heaters is figured as the asphalt. on a dry basis.

An emulsion, such as herein described, is not per se my invention, and can be obtained on open market under the trade name of K-B emulsion.

With these hydrocarbon resinous ingredients, which constitute the thermoplastic stiffening agent, I preferably add a small amount of casein dissolved in an alkaline solution. Instead of casein, I may use any other ingredient, which when precipitated by a precipitating agent carried down with it the stiffening materials in a more or less conglomerate mass. Thus, in lieu of casein, I may use. rosin size, viscous animal size, or other equivalent material. In some cases, however, I do not utilize either casein or the sizing matemixed with the fibrous material in the beater by continued rotation of the beater roll adjusted somewhat away from the bed plate, I then add 10 parts by weight of alum as a precipitating agent. The fibrous stock with the stiffening agent thoroughly incorporated therein is now formed into a felted sheet by a cylinder paper machine, and, when the sheet is of the desired thickness, it is cut and removed from the make-up roll. The sheet is then dried for the removal of water; and, when dry, is relatively open, free and porous with free rosin, gilsonite, Montan wax and asphalt distributed as discrete particles throughout the sheet, and, when magnified, are visible as such. lVhile still warm from the drier, the sheet is now preferably passed through calender rolls heated to a sufiicient Of course, by taking a rial last referred to, but ordinarily I find.

temperature to flux the hydrocarbon stiffening agents so that they will ccialesce throughout the sheet. The effect of the calendering is further to condense and compact the sheet, so that, when the sheet cools, it is relatively hard, compact or dense, stifl and resilient; and it is not afl'ected by body temperature or materially affected by solar heat, but may berendered limp and flexible at a temperature .of 140 to 150 F.

the residue after cutting out the box toes or other shoe stiifeners, must he disintegrated before being added to the heater. 1 find that this distintegration may be accomplished bysubjecting the. material to the action of an Abbe" rotary cutter or grinder.- Such machines are on the market and are easily procurable. Since there is some tendency of the stiffening agents in the waste to gum the knives, I employ as a preventative a small amount of talc which may be thrown into the grinder from time to time by the handful.

For example, I find that in any given amount of the distintegrated waste fiber, there need not be over 70 of tale to in sure the successful operation of the grinder. The disintegrated waste material consists of the usual fibers of which the felt was formed together with the gums or solid hydrocarbons with which it was impregnated. It "is possible to reduce the proportion of the asphalt emulsion from 30 parts by weight to, say, 20 parts by weight, and to increase the percentage of the casein orbther size which is employed.

By long continued experiment, I have found that a sheet, having only the asphalt emulsion as the stiffening agent, does not produce satisfactory box toes, for the reason that the sheet is too soft and does not possess the requisite rigidity and resiliency when cold, and that further it becomes too limp and soft when heated in the usual heaters employed in shoe factories in connection with the pulling and lasting operations. I regard, however, the employment of the asphalt emulsion as desirable for the reason that the normally adhesive asphalt imparts a certain desirable toughness to the sheet when it is warm, and contributes towards permitting the box-toe blanks to be folded and stretched about the last when the shoe is being pulled over or lasted. Since the asphaltic emulsion is in sufiicient to produce a sheet of necessary resiliency, rigidity and stiffness, I employ rosin,

gilsonite or the equivalent which is distribpenetrability when molten, acts as a fluxing agent for the other hydrocarbons in the sheet. The-addition of Montan wax or like hydrocarbon of high penetrability and relatively low melting point is particularly desirable when a tempering agent such as gilsonite is employed, as otherwise itmay be necessary to heat the calendering rolls to such a high temperature to flux or coalesce the other hydrocarbon ingredients as might or would tend to burn the long fibers employed in making the sheet. An advantage in employing asein rather than other size is that when precipitated with alum it is not affected by dry heat but will soften when moist. Ordinarily,

in the pulling over or lasting of shoes, in which stiffened box-toe blanks are employed,

it is customary to subject the blank to moist heat, and therefore it is desirable to use some agent which when precipitated is not affected by dry heat but which will soften when sub jected to heat and moisture.

After the sheet is finished, the blanks are cut and skived to serve as shoe stiffeners, such,

as box toes or counters.

The stiffening agents may be referred to as thermoplastic material, meaning to include -1. A box-toe material, consisting of a by that term those compounds or mixtures which function as herein set forth,namely those which may be incorporated in the wet .mass of fibrous material while ina finely divided condition, which soften on the appli-' cation of heat not injurious to the shoe, which set rapidly when cooled, which give rigidity, stiffness and resiliency to the molded box toe, and which will permit the heated and binder. 2. A box-toe material, consisting of a fibrous pulp and relatively longer vegetable fibers of the class described distributed throughout the same in felted relation therewith and impregnated with a thermoplastic binder, the proportion of vegetable fibers being no greater than that of the fibrous pulp.

3. A box-toe material, comprising a waterlaid felt, consisting of rag pulp and much longer vegetable fiber distributed therewith and impregnated a thermoplastic through and in felted relation therewith, and

impregnated with a thermoplastic binder.

4. In a water-laid felt, a fibrous foundation consisting of a rag pulp, and much longer vegetable fiber distributed throughout the mass in felted relation therewith, and capable of being impregnated with a thermoplastic binder.

5. In a water-laid felt, a fibrous foundation consisting of a rag pulp and relatively longer ligno-cellulosic fiber of the class described, uniformly distributed therethrough.

6. A felted fibrous foundation consisting of about equal proportions of fiber of a length of the order of magnitude of rag or i wood fiber and a fiber of a len h of the order of magnitude of' rope or ax fiber, said foundation being impregnated with sufiicient thermoplastic binder to be serviceable as a thermoplastic box-toe material.

In testimony whereof I have aflixed my signature. I'

. ALBERT L. CLAPP;

limp box-t'oe blank to be stretched about the. I

toe endof the last, in-the' pulling-over and end-lasting operations.

This application is a division of my aperial No. 740,414, filed Septemplication ber-27, 1924, which in turn is a division of my application Serial No. 598,214, filed October 31, 1922, and which issued onfJuly 7, 1925, as Patent No. 1,544,813.

What I claim is fibrous pulp and a relatively longer vegetable fiber of the class described distributed 66 throughout the mass in felted relation there-