US1843581A

US1843581A - Method of making fiber-rubber material

Info

Publication number: US1843581A
Application number: US212356A
Authority: US
Inventors: Reed P Rose; Allen F Owen
Original assignee: Mechanical Rubber Co
Current assignee: Mechanical Rubber Co
Priority date: 1927-08-11
Filing date: 1927-08-11
Publication date: 1932-02-02
Anticipated expiration: 1949-02-02
Also published as: GB295387A; FR658793A; DE588344C

Description

H Patented Feb. 2, 1932 expensive,

man sTATEsPATENT OFFICE REED r. ROSE AND ALLEN r. owEN, or JAoxsoN HEIGHTS, EW YoiiK, ssIeNons 'ro THE MECHANICAL RUBBER COMPANY, or CLEVELAND, 01110, A CORPORATION on NE JERSEY METHOD or MAKING FIBER-RUBBER MATERIAL No Drawing.

' more particularly to a leather substitute suitable for uses similar to those in which sole leather is employed.

Leather of the sole leather type has a wide use inrthe arts, more particularly for shoe parts such assoles'and doublers, counters and toe boxes, belting, gaskets, pump valves and cups, shims such as body shims for. automobiles and many other purposes. However, leather of this characteris relatively since for the highest class articles only selected parts of the best grade hides can be used; Moreover, while sole leather has many desirable qualities which fit it for the above and other purposes, it is open to a x number of objections the most important of which is lack of uniformity which is apparent not only between different lots butto a great extent even in the individual hides. itstensile strength and resistance to flexing and abrasion are relatively good, there. is Y room for considerable improvement in these respects, and it is also open to the objection that it is water-absorbent, and when water soaked, it loses its resistanceto abrasion and cutting. and loses in tensile strength,and it has the further disadvantage that after drying,,itbecomes unduly stiff and does not recover its original physical characteristics. Furthermore, it deteriorates in the presence of strong alkaliesand acids, and hence cannot be used for purposes where resistance to these is required. An object of our inventlon is to provide-a uniformly dense, tough,.high tensile, flexible,

water and abrasion resistant composition. of

fiber and rubber. Another object is to provide a sole leather substitute which can be used for every purpose for which sole leather is now used having properties substantially equalling or surpassingthose of' geninue leather. Another object is to provide a finished shoe bottoming blank directly from an aqueous'suspension offiber and rubber. further object is to provide shoe soles, dou blers, counters, toe boxes and other findings of improved quality and to provide an inexpensive method of manufacturing the Application filed August 11,

, While 1927. Serial No.. 212,356.

same. A still further object is to provide a method of preparing and treating the composition by which the desired qualities are obtained. Further objects will appear fromalone or compounded, the material being.

characterized by its density, toughness, high tensile and high flexing test, and resistance to water and'abrasion. The invention further comprises the method for making the material.

In carrying out the invention, an aqueous suspension of fiber mixed with an aqueous dispersion of rubber is first prepared. While it is preferred to use vegetable fibers such as cotton any other fiber or mixtures thereof possessing the desired characteristics may be used. The cotton or other fiber is first partly hydrolized in any"'suita-ble manner preferably by treating with water in any suitable type of a heating engine or hollander. The beating operation is carried outwith care so that the fibers are drawn or brushed out and not cut fine andis continued until the fiber has been hydrolized to such an extent that the fiber surfaces have been reduced to a gelatinous condition. Any suitable aqueous dispersion of rubber, latex, unvulcanized or vulcanized, or an artificial dispersion of rubber,- is then added to The invention also includes the addiif" desired, of any suitable compoundfilling ingredients including protecas glue, treated starches,

tion, mg or tive colloids such casein, etc. and

which-it is desired to. modify the properties.

After the batch .is thoroughly mixed, the

such as natural I any other ingredients by the above prepared aqueous suspension of fiber.

coagulation. It is preferred-to utilize the two-sta e method of depositing the rubber ished article in any of the following ways:.

The solid material of the batch may be deposited in sheet form of the desired thickness directly from the suspension in water by the use of a paper machine of theFourdrinie'r or cylinder type. After the formation of a sheet of suitablethickness, the wet sheet is then cold pressed preferably between the plates or platens .of a press at a pressure not to exceed that at which the sheet will flow or spread while in its wet condition. The main purpose of this pressing is toremove moisture and to initially consolidate or compact the material. The pressure used can be between the limits of 50 to 500 lbs, but for the higher pressures it is preferable to apply it gradually in order not to distort the position of the fibers inthe sheet and spread the same. If products of a medium quality are desired such as shoe doublers or mid-soles, counters,

I toe boxes and automobile body shims the moisture content may be reduced to form 10-15% in one drying operation. However, if a better quality product is desired the drying step should be carried to a point where the material contains between 20 and 30% moisture and should be followed by an intermediate pressing step; using a pressure of from 500 to 1200 lbs. per square inch with a cold press. After this intermediate pressing step the dryin is continued until amoisture content of rom 10-15% is reached. After the cold pressing the sheet is dried in any-suitable manner until its moisture contenthas been further reduced. Fol: lowing the drying step, the sheet is then hot pressed at a temperature and under a pressure which will vary somewhat with conditions and the urpose for which the finished material is to e used.

That is, if a relatively high heat and long pressing are employed, the pressure may be somewhat reduced, while if the heat is lower and the pressing of comparatively short duration, the pressure should be greater. Other things being equal, the higher the pressure the greater the density, toughness, tensile strength, .water and abrasion resistancev of the sheet, but if the pressure is unduly high, the flexibility maybe decreased to such an extent that the material is nb longer suitable for shoe bottoming purposes requiring considerable flexibility but may .be-used for other purposes where flexibility is not an essential factor. The pressure should not be substantially below 800 lbs. in the making of a sole or doubler material, and by reason of the aforesaid decrease in flexibility, it should not substantially exceed 2000 lbs, the pr eferred limits for the pressing being from about 1200 to 2000 lbs. at a temperature of from 225 F. to 310 Fffor these products.

While, if desired, vulcanizing ingredients may be included and the material vulcanized, satisfactory results are obtained Without vulcanization. After the final pressing step the material, if to be used for shoe bottoming, is

then cut into the desired blanks, and in this connection it may be pointed out that the characteristics of the material are such that it may be channeled,- skived, stitched or otherwise treated in the same manner as genuine leather and by the use of the same machinery. Where flexibility is not a paramount requisite the pressure limits may'extend beyond 2000 lbs. as for example in using the material for purposes such as pump valves, cups, etc.

Instead of forming the wet sheet on a continuous type of paper machine such as the Fourdrinier or cylinder type it may be built up by the use of a wet or board machine, plying up on a suitable pick up or making roll to the desired thickness, and then removing the sheet. If desired, an aqueous dispersion of rubber, such as natural or artificial rubber latex, may be sprayed or otherwise applied between the layers as they are plied up on the making roll and the'latex may be com pounded with glue or other. suitable ingredients for the purpose of increasing or decreasing the adhesiveness, tensile strength, etc. of the dispersed rubber. If glue is used it may beset or not as desired by. the use of formaldehyde, tannic acid or other suitable agent. The use of glue in this way improves the bond between the plies and also adds tothe water resistance. The wet sheet as obtained from the cylinder machinemay then be subjected to the same pressing and drying operations as above described in connection with theproduct from the continuous sheet forming machine.

As an alternative to either of the above methods of forming thewet sheet, it may be produced by centrifugal deposition from the suspension in the following manner:

, An ordinary centrifugal may be partitioned off into compartments either vertically or horizontally by pairs of walls of finely perforated'metal or/ot-her suitable material spaced sufficiently to give the. desired thickness of material and opening into a common cylindrical compartment running vertically and parallel with the periphery of the basket. 0n supplying the machine with the fiber-rubber. suspension, the material will be deposited in a sheet between the thickness,

partially built in the the case with a master walls.

sion of fiber and rubber, obtained as before described may be partially dehydrated by allowing it to settle or by any other suitable means and then the wet fibrous mass placed in asuitable mixing apparatus, such asa Werner-Pfieiderer mixer, and an additional amount of natural or artificial latex, such as a dispersion of rubber in water with or without the addition of glue or other suitable protective colloid, is added to the batch in the mixer, and the mixing operation continued until the added rubber and other ingredients are uniformly distributed throughout the mass. No coagulating step is used upon the portion of'the rubber added to the batch in the mixing machine'and if the proper protective colloid is used, coagulation. does not take 'place until the material is dried. This mixing is continued until the batch is in a proper condition to be extruded through a suitable apparatus, which may be an ordinary tuber or pug mill fitted with an. orifice capable of giving a shape to the material approximating that desired in the finished product. The material may be cold pressed, dried with or without the intermediate pressing and then hot pressed as previously described. Alternatively, the product from the mixing machine may be partially dried down to a moisture content of between 2030% and then made into sheet or ribbon form by any suitable means.

Another method of forming a sheet is to place the rubber fiber mixture between'two moving convergent wires or felt surfaces form of a vertical hopper so that as the bodyv of the rubberized fiber moves toward the bottom of the machine it is gradually compacted with the removal of water-until the sheet coming from the bottom orifice of the machine is of desired and with a sufiiciently low mbisture content so sheet frornan ordinary Fourdrinier paper machine. This sheet is then pressed, dried and treated in every way as described above.

- Byour invention a leather substitute may be produced which is similar in appearance to leather of the sole leather or doubler types and in .whi'ch'the fibrous material is distributed continuously throughout the body of thematerial, and is bonded by rubber either from natural latex or from an aque- .may be made therein without departing its spirit, and it is therefore not desired to that it can be handled as is ous dispersion of rubber (crude or reclaimed) uniformly distributed in minute particle form substantially invisible to the naked eye throughout the body of the material to form a'continuous fibroid flexible sheet, having the characteristic appearance of leather, especially after abrasion, being dense and tough, and having a high flexing and tensile test and a high resistance to water absorption and abrasion. Moreover, even after long exposure to moisture, it still.

retains its characteristic properties and is not softened, warped, ,mushroomed and otherwise deteriorated-as is the case with leather. It may be manipulated in the same general-manner and by the same machinery as is used for leather. While it may con tain a relatively high percentage of rubber, it has the general appearance and characteristics of leather and has not the rubberlike feel and appearance of a, similar com-' pound made by mixing fiber 6n a mill with plasticized rubber. Its resistance to abrassion is also vastly superior to that of an ordinary milled -rubber-fiber compound and the abrasion is very uniform.

While a specific disclosurehas been made of the invention, it is obvious that changes from limit the invention more than is required by the prior art and as set forth in the appended claims.

Having thus described our invention, what we claim and desire to protect by lhetters Patent is:

1. The method of forming a fiber-rubber material which comprises forming an aqueous suspension of rubber and vegetable fiber,

depositing the rubber on the fiber, forming a relatively thick wet sheet material therefrom, cold pressing the material without flowing or spreading it to compact it and remove moisture, drying the material to not substantially over 15% moisture, and hot pressing at an increased pressure.

2. The method of forming a fiber-rubber material which comprises forming an aqueous suspension of rubber and-vegetable fiber,

coagulating the rubber on the fiber, forming a relatively thick Wet sheet material thereflowing or spread-ing'itto compact it and remove moisture, drying the material to not substantially over 15% moisture, and hot pressing at over 800 lbs. pressure.

3. The method of forming a fiber-rubber material which'comprises forming an aqueous suspension of rubber and partly hydrolized vegetable fiber, coagulating the rubber on the fiber, forming a relatively thick wet sheet material therefrom, cold pressing the 7 from, cold pressing the material without material at not substantially over 1000 lbs.

pressure, drying to not substantially over .ous suspension of rubber to 15% moisture, and hot pressing at over 800 lbs. pressure. i

, 4. The method of forming a fiber-rubber material which comprises forming an aqueous suspension of rubber and partly hydrolyzed vegetable fiber, coagulating the rubber on the fiber, forming a relatively thick wet sheet material therefrom, cold pressing the material at not substantially over 1000 lbs. pressure, drying to not substantially over 15% moisture, and hot pressing at 1400-2000 lbs. pressure.

5. The method of forming a fiber-rubber material which comprises forming an aqueous suspension of rubber and partly hydrolyzed vegetable fiber, coagulating the rubber on the fiber, forming a relatively thick wet sheet material therefrom, cold pressing the material without flowing or spreading it to compact it and remove moisture, material to substantially 10-15% moisture, and hot pressing at 1400-2000 lbs. pressure.

6. The method of forming a fiber-rubber material which comprises forming an aqueous suspension of rubber and partly hydrolyzed vegetable-fiber, coagulating the rubber on the fiber, forming a relatively thick Wetsheet material therefrom, cold pressing the material at not substantially over 1000 lbs. pressure, drying to substantially 10-15% mo sture, and hot pressing at not substantially over 2000 lbs. pressure.

-7. The method of forming a fiber-rubber material which comprises mixing an aqueou's suspension of partly hydrolyzed vegetable fiber and a suflicient amount of an aqueprovide 12-50% rubber, coagulating the rubber on the fiber,

forming a relatively thick wet sheet material .therefrom, cold pressing the material Without fiowing'or spreading it to compact it and remove moisture, drying the material to not substantially over 15%] moisture, and hot press ng at an increased pressure.

8. The method of forming a fiber-rubber -material which comprises mixing an aqueous suspension of partly hydrolyzed vegetable fiber and a suflicient amount of an aqueous suspension of rubber to provide 1250% rubber, coagulating the rubber on the fiber, forming a relatively thick wet sheet material therefrom, cold pressing the material at below 1000 lbs. pressure, drying the material to not substantially over 15 moisture, and hot pressing at over 800lbs; pressure.

, 9. The method of forming a fiber-rubber l I o 4 material which comprlses mlxing an aqueous suspension of partly hydrolyzed vegetable fiber and 'a sufiicient amount of an aqueous suspension of rubber to provide 12-50%' rubber, coagulating the rubber of the fiber, forming a relatively thick wet sheet material therefrom, cold pressing the material without flowing or spreading it to compact it and remove moisture, drying to substandrying the tially 10-15% moisture, and hot pressing at over 1400 lbs. pressure.

10. The method of forming a fiber-rubber material which comprises mixing an aque- -ous suspension of partly hydrolyzed vegetable fiber with a sufficient quantity of an aqueous suspension of rubber to provlde 12-50% rubber, coagulating the rubber on the Wet sheet material therefrom, cold pressing the material without flowing or spreading it to compact it and remove moisture, drying to not substantially over 1 5% moisture, and hot pressing at over 800lbs. pressure.

12. The method of forming a fiber-rubber material which comprises mixing-an aqueous I suspension of vegetable fiber hydrolyzed to a partly gelatinous condition with a sufficient amount of an aqueous suspension of rubber to rovide 12-50%- rubber, coagulating the ruber on the fiber, forming a relatively thick wet sheet material therefrom, cold pressing the material at below 1000 lbs. pressure, dry- I ing to substantially 10-15% moisture, and hot pressing at over 1400 lbs. pressure.

13. The method of forming shoe bottoming material which comprises forming an aqueous suspension of rubber and fiber hydrolyzed to a partly gelatinous condition, coagulating the rubber on the fiber, forming a relatively thick wet-sheet therefrom, drying the sheet to not substantially over 30% moisture, cutting out shoe bottoming articles from the sheet, cold mold pressing the articles at not to not substantially over 15% moisture, and hot pressing at'not substantially over 2000 lbs.

14. The method of forming shoe bottoming-material which comprises mixing an substantially over 1000 lbs. pressure, drying tively thick wet sheet therefrom, drying the sheet to not substantially over 30% moisture,

cutting out shoe bottoming'articles from the sheet, cold mold pressingat not substantially,

over 1000 lbs. pressure, drying to substantialpressing at a ly 10-15% moisture, and hot pressure of 1400-2000 lbs.-

15. The method of manufacturing a fiberrubber material which comprises forming a wet sheet of intimately intermingled. rubber particles and fibers,"pressing the Wet sheet at room temperature Without spreading it, drying the wet sheet to a moisture content of not over 15%, and pressing and completely drying the sheet at an elevated temperature.

16. The method of forming a fiber-rubber material which comprises mixing an aqueous suspension of partly hydrolyzed vegetable fiber and rubber latex, coagulating the rubber on the fiber, mixing therewith a rubber vlatex in the presence of a protective colloid,

forming an article therefrom, partially dehydrating the material, cold pressing under moderate pressure, further dehydating, and hot pressing under a higher pressure.

17 The method of manufacturing a fiberrubber material which comprises forming a watery body of partly hydrolyzed vegetable fibers intimately associated with ooagulated rubber particles, mixing therewith a water suspension of rubber in the presence of a protective colloid, shaping an article therefrom, partially dehydrating, cold pressing, further dehydrating, and hot pressing under a higher pressure.

18. As a new article, a fiber-rubber material comprising a dense, compressed, relatively thick, flexible sheet of closely matted relatively long vegetable 'fibers, the individual fibers being spaced and strongly united by a relatively thin bond of gelatinized hydrated cellulose and the deposition product of an aqueous rubber disperslon.

Si 'ned at New York, county and State of New York, this 5th day of August, 1927 REED P. ROSE. Signed atCleveland, county of Quyahoga and State of Ohio, this 8th day of August,

ALLEN F. OWEN.