US1817323A - Process of making rubberized sheet materials and products - Google Patents

Description

Aug. 4, 1931. H. D. RICLE 1,817,325;

PROCESS OF MAKING RUBBERIZED SHEET MATERIALS AND PRODUCTS Filed March 22. 1929 by l "m' 2'1 )1: Harold D. R 1 c 1: Y 3 W1 4 w 4TTORNV Patented Aug. 4, 1931 UNITED STATES PATENT OFFICE HAROLD D. RICE, OF BRISTOL, RHODE ISLAND, ASSIGNOR TO WOONSOCKET RUBBER COMPANY, OF MILLVILLE, MASSACHUSETTS, A CORPORATION OF RHODE ISLAND PROCESS OF MAKING RUBBERIZED SHEET MLATERIALS AND PRODUCTS Application filed March 22, 1929. Serial No. 849,071.

This invention relates to a process for making rubberized sheet material, more particularly to a sheet material having the characteristics of finished leather, and to the product. 1

There are a number of substitute or imitation leathers on the market in which a fabric base is provided with a nitro-cellulose or similar coating treated to simulate various leather effects. These products are relatively expensive to make by reason of the use of a cloth backing, and by reason of the number of spreading and other operations required to apply and properly finish a nitro-cellulose 16 coating of the required thickness. In addition, materials of this character depend almost wholly for their strength on the cloth backing. Furthermore, unless the edges of the cloth backing are treated in some manner 20 they tend to fray in a comparatively short time, giving a. ragged edge.

An object of the present invention 1s to provide a method for making a rubberized sheet material which is cheap, durable, flexible, waterproof throughout, having a relatively high tensile strength, gi ing an edge which when out resembles that of leather, having no tendency to fray, and which can be 'ven various finishes to simulate different leathers. The invention also comprises the article.

The invention broadly consists in hardening relatively cheap fibres into a bat, impregnating the bat with rubber in fiu1d form,

5 compacting the bat, coating it with rubber,

and where embossing is desired first superficially treating the coating with a halogen and then embossing, vulcanizing and fin sh- "ing the material by a surface halogenating treatment.

For a complete disclosure of the nature and objects of the invention, reference is had to the accompanying specification and drawings,

in which latter:

Fig. 1 is a perspective of a piece of completed hardened hat of fibre;

Fig. 2 is a similar view showing the piece after impregnation with rubber and partial consolidation;

Fig. 3 is a similar view of the piece as reduced to its final thickness by pressing;

Fig. 4 is a perspective of a piece of the finished sheet material; and

Fig. 5 is a diagrammatic view of a suitable apparatus for impregnating the bat.

In carryin out the invention, a bat of fibres is first ormed, preferably by blending fibres of rayon, hemp, wool and cotton in a blender and picker, the blend then being made up into a hat on a cross forming carding machine, superimposing one thin layer on top of another, with the fibres in one layer running at right angles to those in an adjoining layer, until the desired weight is attained. A suitable blend of fires is rayon 50 parts, wool 10 parts, cotton 20 parts, and hemp 20 parts. While the invention is not limited to the specific amounts given or to the s ecific kind of fibres named, the abovedescrlbed blend has been found very, suitable. The rayon is valuable by reason of its long fibre, its cleanliness and low cost. The hemp also has a low cost and imparts strength. The wool is valuable for its hardening characteristics; and the cotton is used as a filler. While a straight forming carding machine can be used, it is preferred to use a cross forming carder, since it gives a stronger bat with greater resistance to bearing and separation after impregnation. If desired to obtain still greater strength, a woven cotton web, such as an open sheeting may be introduced near the middle of the bat, between two layers of the carded material.

The bat is then subjected to a rocess known in the art as hardening, which imparts sufficient strength for succeeding oper' ations. In this operation the bat is wet with water, folded up on itself, and operated on by hammers which act to compact the fibers to some extent without, however, felting them together in the sense that the term felting is ordinarily employed. The moist batis then unfolded and is ready to be im'- pregnated with rubber.

The bat 1 thus produced is relatively loose and thick, and has the general appearance as shown in Fig. 1. While the bat may be dried and impregnated with rubber in the form of cement, it is preferred to operate directly on the moist bat and impregnate it with a water dispersion of rubber, such as natural or artificial latex.

In Fig. 5 there is shown a suitable form of impregnating apparatus, in which the bat l is drawn over a guide roll 2, before entering the latex bath 3. The' bat then passes underneath a roll 4 partly submerged in the latex and passes from this roll beneath a second roll 5, and then between the rolls .5 and 6, and finally between the rolls 6 and 7. During its passage through the bath the bat becomes any excess 15 squeezed out by the rolls 5, G and 7; which also partlyco nsolidate the bat. The

top 'roll-7 preferably has a rubber surface, "whilethe other rolls may be of metal.

it natural latex is used, it is preferred to employ alatex which has been subyectcd to on'e'of the well-known'creammg processes,

which the water solubles present in the i latex are greatly reduced and the latex concentratedQ However, normal latex, vulcanized'latex or any suitable artificial dispersion of rubber. may be used. A suitable latex comound is asfollows:

Zinc oxide M Pigment CAPUOOU W The Nekal in the above formula is condensation product of an aromatic hydrocarbon with an aliphatic alcohol in the presence of sulphuric acid. It acts as a preservative and increases the penetrating power of the dispersion. The above formula is merely il lustrat-ive, and the ingredients named may be replaced in whole or in part by other suit able ones. For instance, any other accelerator may be used in place of the heptaldehydeaniline condensation product, but it is preferred in aii cases to use an acceleratorfunctioning at a lo w enough temperature to avoid any possible injury to the fibres by too great or too long heating. Any other suitable antioxidant may also be employed, well as other filling or coloring materials. In making up the latex composition it is diluted with water until the total solid content is approximately 40 per cent.

After the impregnated bat issues from between the rolls 6 and 7, the rubber in it is Softeners (such'as'parafii-n'fiwax, pme' 7 the acid. After coagulation by thea cid or:

other coagulant used',' th'e' bat may be passed through a series of washing tanks, to'rmove the coagulant,.andthen passed into a drying chamber as before, and appears as shown at 8 lHgFlfZ. 2. If. desired, the bat may be passed through the latex bath a second time and againdried; v i From the drying.chamberkthevmaterial is passed throilgh a series? of 'ca lendar wells, to bring it to the desiredithioknesgto. give-it a uniform surface, and to thoroughly .zmatath e fibres gently together,=. about as: shown" at 9 in Fig. 3. 1-; p2: The material is nowready for coating with a rubber compound, and-,this icompound may be conveniently applieda'by the llsual oalem dering process. 'Howeverg'. if? desired, the rubber coating may be appliedas a-dough-by the usual formof spreading mahin,e-,-.--or instead of a dough of r milled: rubber-,3: latex 'composition prepared for {spreading may be used. A suitable'rubber conipoundion coating the material-is as follows. a l

tar, Montan w-axje'tc. Ground chronie'leather- Formaldeliyde ethylam'he: .condensa-w' tion' product Zinc oxidel The above formulaiis in'erel and it may be variedin" whole r suit conditions. In placeof t-li' I I or amehyde-ethylamine condensation product, such accelerators as ftetrarnethylthiuranimonosulphide, tetramethylthiuram s ber compound used forcoatin giscontrolled by the weight of the felt t'o 's't-art "u ith-. In starting with a -'16 ounce felt-im regnated with 16 ounces of latex compound, it*'isnec essary to coat with 16 ounces of rubber compound, considering the width of 'ther'felt 54 inches per linear yard.-

Itan embossed finish is 'desiredfthe ber coating is next superficially' treat-ed v with a halogenating material, such as .sul-phur chloride, in order to set or harden the rubber "cry slightly in from the surface, so that it will retain the configuration impressedupon it by the embossing piates. While the sulphur chloride may be applied in any desired form and by any suitable method, it is prefered to spread a 7% per cent solution of the sulphur chloride in carbon tetrachloride, as by the spreading operation the reaction can be better controlled. Following the sulphur chloride treatment, the material is then embossed by the use of any common embossing apparatus. Following the embossing step, it may be given a two-tone finish by spreading on the rubber surface a 1 hin rubber cement of a contrasting color to that in the rubber coating compound, so as to more or less fill the indentations formed by the embossing dies. If a plainfinish and not an embossed one is desired, the before described sulphur chloride treatment and the embossing may be omitted. The material may also be made up in single colors and embossed. If desired, a coating may be spread or calendered on the inside surface. This inside coating may or may not be embossed.

The embossed or plain sheet is then cured in any suitable manner as in an open heater, and, as before pointed out, it is preferred to use low temperature vulcanizing combinations, both in the impregnating compound and the coating compound, in order that the fibre may not be sub ected to an unduly long heat or excessively high temperature.

After vulcanizing the material, the coating is given a finishing treatment with a halogen, which may be a sulphur chloride solution or a bromine solution, but preferably both are used. For instance, the surface of the coating may be first treated with a 7% per cent solution of sulphur chloride in caron tetrachloride, and this treatment followed by one with a 2 to 3 per centsolution of bromine in carbon tetrachloride, or instead a single solution is used of the two ingredients in about the same proportions. The succesive treatments with sulphur chloride and bromine-impart a somewhat hard and glossier surface. However, the combined treatment is a little more convenient, as it involves only a single step. If desired, he vulcanized material may be given a thin coating of shellac before the final surface halogenation, or the vulcanized rubber surface may be halogenated, shellacked, and ,"gain halogenated.

It will be seen that by the present invention a sheet material 10 has been produced which is cheap, durable, tough, has a very high resistance to tearing, and uniformity of strength, both crosswise and lengthwise of the fibres, which is waterproof throughout, which has a cut edge resembling that of leather, and which has a surface feeling free from harshness and very similar to that of the ordinary embossed leather used for upholstery, luggage, and other purposes. In addition, the material has great resistance to fibrous sheet material with rubber, applying a coating of rubber to the sheet, superficially treating the coating by halogenation, embossing, vulcanizin and finally halogenating the finished sur ace.

2. A method of making a leather substitute which comprises forming a shee-t'bat of mixed vegetable, animal and artificial fibres, im-

pregnating the bat with a water dispersion of rubber, drying, consolidating the bat, applying a coating of rubber, superficially treating the coating with sulphur chloride, embossing, vulcanizing, and halogenating the finished surface.

3. A method of making a leather substitute which comprises impregnating a sheet hat of fibres with a water dispersion of rubber, drying consolidating the sheet, applying a coating of rubber, superficially treating the coating with sulphur chloride, embossing, vulcanizing, and forming a finished surface by treatment with bromine.

4. A method of making 'a leather substitute which comprises impregnating a sheet hat of fibres with rubber latex, drying, consolidating the sheet, applying a coating of rubber, superficially treating the coating'with sulphur chloride, embossing, vulcanizing, and halogenating the finished surface with bromine and sulphur chloride.

5. A method of making a leather substitute 3 which comprises impregnating a sheet hat of fibres with rubber latex, drying, consolidating the sheet, calendering a coating of rubber thereon, superficially treating the coating by the application of sulphur chloride in solution, embossing, vulcanizing, and successively treating the coating with solutions of sulphur chloride and bromine.

6. A method of making a leather substitute a which comprises impregnating a sheet bat of fibres with rubber latex, drying, consolidating the sheet, applying a coating of rubber, vuleanizing, and finally halogenating the finished surface with bromine and sulphur chloride.

7. A method of making a leather substitute which comprises impregnating a sheet bat of fibres with rubber latex, drying, applying a coating of rubber to one surface, superficially treating said coating with sulphur ehlo ride, embossing, applying a coating of rubber on the other surface of the fibrous material, vulcanizing, and halogenating both surfaces with bromine and sulphur chloride.

8. A method of making a leather substitute ITD ' which comprises ct sheet hat harclepmg .fpressupe, 1mplteg-nat 1 face a cdating of x and h-av m ggn ones water dispersion of o id-Ming. 2 23 mb 1 rubber, yulcap'izing, 3111 v ated finished surface by ahno sheet, applyingagqgy mg of 1- tel-i211 coml'nisipg ac P/551E ?.halg i Signed at Bristol,

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