US2077017A - Paper - Google Patents

Description

April 13, 1937. E. c. SCHACHT PAPER Filed Oct. 27, l952 Patented Apr. 13, 1937 UNITED STATES PATENT OFFICE PAPER Elmer C. Schacht, Troy, N.Y.. aasignor to Behr- Manning Corporation, Troy, N. I, a corporations which matured into said patents.

The principal object of the invention is to produce sheet materials, particularly those 01 my 10 aforesaid applications, that is, flexible materials comprising (1) a web of a mixture of separators such as comminuted cork and fibre having a.

resinous binder incorporated therein in accord- H ance with my earliest application and (2) a web 1 the laminae of which comprise cork or other separator and fibre and fibres respectively and in which is likewise incorporated a resinous binder in accordance with the second or the above-mentioned applications. To obtain these sheet me.- go terials, I have developed a method which is efllcient for'large scale production and enables uniformity to be obtained in the final product.

Broadly speaking, I am particularly concerned with producing these various paper-like mate- 25 rials by a method wherein the sheets are formed as single ply webs, i. e., non-laminated webs on the usual Fourdrinier machine or are built upoi plies after the manner of paper making practice in which a cylinder paper making machineor multiple Fourdrinier machine is employed and wherein the respective stocks are i'ormed into laminated webs and felted together in the machine. I

Thus I will follow this invention in producing (1) single ply webs; and (2) multi-ply webs, the latter having its lamina composed 01 (1) a mixture of separators and fibres; (2) fibres exclusively and (3) certain laminae composed of fibres 40 and separators and other laminae of fibres exrious structures binder materials in predetermined percentages, so that the respective laminae of the ultimate sheet will contain: I

(a) The same percentages of the same binder;

(b) Difierent percentages of the same-binder;

(c) The same percentages of different binders; and

(d) Different percentages of different binders, whereby the characteristics of the respective plies can be controlled. 7, u u

The binder preferably employed consists of a natural resin or synthetic resin, of which many commercial types are known, and I prefer to use synthetic resins, particularly those of the Bake- 55 lite and alkyd types, the latter known commerclusively. I incorporate in the webs of these va- 1932, Serial No. 639.906

cially as glyptaP'. resins. With such resins, or when a natural or synthetic binder be employed, curing orv treating agents which will determine the character or condition of the resin in the sheet will preferably also be utilized.

7 Again, I obtain a single ply or integral stratified web in which the lamination or laminations of the built up structure are controlled as to (1) relative density, and (2) components, that is the kind and amount of (a) fibres, (b) comminuted cork or other separator, and (c) binder present. The relative densities of the layers will be controlled by the size of the cork particles, the type 1 of ffibre used,-a.n.d the length of time that the stock is subjected to'beater action and the percentage of the respective components. The structural components of: one layer may be composed solely of fibresand that of another layer of comminuted cork and fibres; the layersmay be formed solely of fibres and of respectively diflferent types, or solely of a mixture of cork and fibres and of variable mixtures respectively. The binder employed may be the same throughout the stratified web or each layer may have a difierent binderincorporated therein. The amount of binder present is regulated with respect to concentratio: and also with relation to the density of the we In this way, control of the coefllcients of (1) absorbency, (2) strength, and (3) resiliency, i. e., compressibility and rebound, may be had and varied at will (as well as relative flexibility and stillness) in the ultimate product.

Avery important object of the invention, therefore, isto produce sheet materials of the character of my aforesaid applications wherein a very precise controlmay be had of the structure of the sheet. a

The. method embodies paper making practice as describedwith either of several final or intermediate steps which are each efiicient to 111001? porate the binder. Thus I proceed (1) by a method of saturation after theweb is formed; (2) by recourse to pre-mixing, i. e., mixing the binder with the otherv components before the stock. is beaten, or (3) by beater addition, that is adding the binder to the stock in the beater;

In each-case the control features outlined above are available, can be operated with exactness and enablea uniform sheet to be obtained.

Sheet material according to this invention may be formed to have the following alternative structures:

a (a) Facing layer and bottom layer (1:) Facing layers and intermediate layers (0) Alternate layers corresponding to the respective facing layers and bottom or intermediate layers. I

(a) (b) (0) wherein the facing layers are (1) Thin, equal to or of less thickness than the bottom layer or intermediate layers, or vice versa. of less density than the bottom layer or intermediate layers, or vice versa. Of the same structural components or mixtures as the bottom layer or intermediate layers or vice versa.

Of a di flerent structural component or mixture than the bottom layer or intermediate layers, or vice versa. Permeated with the same binder as the bottom layer or intermediate layers, or

vice versa. 4

Permeated with a different binder than the bottom layer or intermediate layers, or vice versa.

Permeated with a greater amount of binder than the bottom layer or intermediate layers, or vice versa. Permeated with a binder of greater concentration, i. e., having a higher percentage of binder than the bottom layer or intermediate layers, or vice versa. Permeated with a binder compatible or harmonious with a desired surface coating or finish.

((1) Each of the products of (l) to (9) inclusive provided with (1) a facing, (2) a backing, (3) a facing and backing and (4) a core of flexible or stiff preformed material such as paper,

cardboard, vulcanized fibre, cloth or open mesh fabric, synthetic resin, or vulcanized latex or rubber, forming a flexible or stiff permeable or impervious reinforcement.

It is an object of the present invention to produce sheet material capable of wide application, which may be decorated, is light in weight, soundproof, abrasion or wear resistant, inert with respect to the action 'of water ororganic and inorganic solvents, and porous and absorbent or impervious and non-absorbent.

The products of the present invention are useful in the manufacture of gaskets and sealing material, rug anchors, press blankets for impression cylinders of printing machines, floor coverings, artificial leather, wall board, panel material, breaker strips for doors and jambs,

i. e., for refrigerators, electric and heat insulating material, anti-squeak material, channel material, soundproof material, insoles and table tops, as well as numerous other applications. The sheet materials are characterized by (1) high tensile strength, (2) resilience, i. e., compressibility and rebound, and (3) flexibility and pliability in that the sheets may be sharply flexed or creased without cracking or the formation of weakened areas.

I attribute the excellent qualities of these products in part to the method employed in their manufacture. Webs of the structure described without a' specially incorporated material will be resilient and cellular by reason of the presence of the cork, and strengthened because of the fibres, but are subject to cracking and formation of permanent weak areas under sharp flexing.

I prefer paper making practice because the web obtained may be controlled very exactly, and likewise the incorporation of the binder which is essential to the production of my sheeted articles can be precisely regulated and acbe described as hinging or pivoting of the fibres on the cork particles, thereby forming a strong and resilient web characterized by numerous voids and interstices. In other words, from a careful examination of the sheeted articles having the binder incorporated therein and formed by this method, it has been determined that when the cork fibre sheet is bent, cracked, or deformed, what actually occurs is that the fibres at the point of deformation are relieved to cause the cork particles which separate the fibres to compress. This allows the fibres to accommodate themselves or become 'aligned instead of being forced to absorb the entire strain and therefore become ruptured. The cork being highly compressible, returns to its original shape after the strain has been removed, and this causes substantially all of the fibres to resume their original positions in an unbroken state. Thus the sheeted articles under abnormal strains will not retain permanent lines of cracking or breakage. The sheet materials are moreover cellular and absorbent, i. e., capable of exerting capillary effect and the web may be treated uniformly throughout its interstitial mass to improve the inherent characteristics and enhance its flexibility, strength and resistance to bending strains. By reason of the method of this invention, the stratified web will have its respective layers simultaneously produced and bonded together as by felting. In other words, I find that by controlling the make-up of the web andthe incorporation and selection pf the resinous binder, that the normal characteristics of the web are improved and such weaknesses as lack of resistance to bending strains and tearing strains are effectively corrected.

It is an aim of the invention to produce a web or sheet adaptable for floor coverings or other applications where a wear resistant surface is required. In such a case the facing layer will be provided with a resinous binder having (1) a veryvstrong bonding coefllcient, (2) abrasion resistant and resistant to the eifect of water, solvent or chemical action and (3) present in large enough amount to insure the desired result. The bottom or intermediate layer may have any suitable type of binder or the same binder, but the binder will be present preferably in much less amount in the unexposed portion of the web.

Thus a floor covering made as a cork fibre product will have its top layer made as a highly absorbent structure which would, in a saturating process, take up a great deal of resin, rubber latex, or some glutinous adhesive so as to give the covering a high wear coefficient, and plain fibres will also in some cases be used in this top coarse cork particles and fibre so as to have agood non-slip surface, as where it is used for small rugs.

Similar floor coverings would likewise be made by introducing a high percentage of resin or rubher by. pro-mixing or beater addition during the paper-making process in the top ply at which times a lower concentration of resin or rubber will be introduced in the intermediate or bottom plies, thus saving on the cost of saturant, while producing a very acceptable product that has a high wear coeiiicient on its surface. 4

In the manufacture of artificial leather I will preferably resort to the laminated structure hav ing a cork and fibre mixture layer or layers wherein the top surface is composed exclusively of fibre and of high density, so as to absorb just as little of the saturant and give the high native paper strength. This all-fibre ply may be calendered.

25 acceptable artificial leather is made in the same manner by the use of rubber latex or resins introduced either during the paper-making process by pre-mixing or beater addition or by subsequent saturation.

A further important object of the invention is to produce press blankets for impression cylinders in the printing industry. Thus I use a single ply web of cork and fibres as produced onthe single Fourdrinier, or a built-up web obtained by using a multiple Fourdrinier or cylinder paper-making machine and permeated with a suitablebinder, i. e., glutinous adhesive, resin, etc., in accordance with this invention. With one or preferably both sides of the resilient web of appropriate flexibility will be combined a backing of preformed material such as paper, cloth, and/or vulcanized fibre, i. e., hard fibre or fish paper if desired.

In the manufacture of insole material, I will produce either a single ply web of cork and fibres, a multi-ply web of cork and fibres, or a multi-ply web of layers of cork and fibres and fibres respectively, and having an incorporated binder such as resin, latex or glutinous adhesive as herein recited. Theprincipal requirements of such material are (1) strength and ability to withstand stitching and sewing, (2) flexibility to maintain the shape of the insole in use, (3) resilience and smoothness so as to be comfortable, and (4) absorbency to take care of perspiration, and all of which I obtain with this invention. The surface layer, whether of cork and fibres or fibres alone, will be controlled as to density, i. e., absorbency, and may be calendered if required. Also a layer of pressure sensitive or heat sensitive adhesive applied to the undersurface of the sheet or any suitable adhesive or gummed surface will be desirable in some cases. Again a backing or facing, or both,

of muslin or other open web fabric, may be combined with the sheet and in fact thin leather,

. paper or cloth may be utilized. The backing of course in such case may carry the adhesive.

A further object of the invention is to produce sheet material for anti-slip rug anchors or bases my Patent 1,888,410.

This product will be sentedtothe fioorandbyreasonofthecellular orporousnature of the web,firmlygripsthefioor surface. I believe this may be due to the compressibility, and porosity of the web forming a multiplicity of. vacuum cups or to the frictional coeillcient of the cork and fibre layer and its relative spongy roughness.

, It is a further aim of this invention to produce a decorated finish on the sheet as described in For example, the web will have a facing layer composed solely of beaten fibres and a bottom or intermediate layer of cork .and fibre mixture. With such a facing layer facing. I'have discovered that the saturation or permeation of a laminated product of this type.

affords a means of producing a very improved coated sheet material. Some 'saturants, such as rubber, interfere with the application of certain finishing coatings. However, the fibre facing layer when applied'to the cork fibre may be readily regulated in characteristics which affect the condition of its surface intended to receive a finishing coating. For example, it may be regulated as to density, as by selection of proper fibres or control of the period of working the mass in the beater. This permits the permeation thereof by the binder to be reduced to a minimum or otherwise regulated by controlling the density of the fibre layer. Again the condition of the surface of thefibre facing layer, as well as the condition of its body, may be-varled as desired in any other respects independently of the cork fibre layer; since its mass is prepared-and may even receive.

its binder, in whole or in part, separately from the cork fibre layer, as described. The combination, therefore, of the paper fibre layer with the cork fibre layer in a product saturated with a binder, enables me to produce a surface which may receive a finish unimpaired in character by the saturant or binder, regardless of the nature of'the finish or of the saturant. For example, if the finish to be applied is one which does not coact well with the binder, the fibre facing may be made very dense, so that it has a very small amount of the resinous saturant therein, or may be separately impregnated, e. g., in the beater or by pre-mixing with a binder harmonious with the finishing material. as well as with the binder of the cork fibre layer. 0n the other hand, if the finish to be applied is one which is improved by or is compatible with the binder, a fibre facing less dense than in the former instance may be utilized and having a. proportionately increased amount of saturant therein. In any ,event, a fibre facing denser than the cork fibre layer is usually preferred.

The above and additional objects and advantages will appear as the description of the invention proceeds.

Figure 1 is a view showing a single ply web of cork and fibre.

Figure 2 is a view showing a. built-up web,one layer of which is formed of fibres and the other layer of cork and fibre mixture.

Figure 3 is a view of a multi-ply web of cork and fibres.

Figure 4 is a view of a multi-ply web of cork and fibres and a facing layer of fibres.

Figure 5 is a view showing facing layers of preformed material and a core of material made in accordance with any of the forms of Figures 1 to 4.

Figure 6 is a similar view of a laminated web method followed for an immersion treatment andalso the type of curing chamber employed with any of the several methods. I

In referring to paper making machines, it will 10 be understood that while I have represented for purposes of illustration in the drawing a cylinder type of machine, a multiple fourdrinier may be used with equal facility, and I use a regular or single Fourdrinier machine where single ply webs are being produced.

The vats for the stock are indicated at III, II and i2, and feed the respective cylinders, the web being felted together and built-up as understood in the art. In other respects, the various parts of the apparatus have been lettered to describe their function.

With reference to Figure 8, it will be noted that a bath is used in which the resinous or other binder is disposed and through which the web is entrained.

The present invention is not restricted to immersion or impregnation since I have found it equally satisfactory to incorporate the binder by pre-mixing or beater addition as above described.

In Figure 8 also I have illustrated a curing and drying chamber wherein instead of festooning the web, which I also do in some cases, it is passed between rolls which may be hot or cold as desired, and this procedure is adopted where the web as completed on the machine contains the incorporated binder. Of course, in some cases I may incorporate the binder by premlxing or beater addition, and thereafter give the web a saturating treatment, from whence it may be carried over drying racks or drying rollers, as desired.

The curing chamber, of course, may take various forms, depending upon the particular binder utilized, and its temperature will be suitably controlled to efiect a setting of the binder.

As a further condition of the method of operation, the speed of travel of the web through the drying and curing station can be controlled, and likewise in the case of the saturating treatment, the web may be wound onto rolls and thereafter, at any suitable time, passed through the bath, or the web may be formed and continuously fed through the saturating apparatus.

With respect to the vats III, II and I2, there may be any number of these, and I have simply shown four by way of illustration. The vats II and I2 will contain the stock for the surface layers, while the vats I0 will feed the cylinders to produce the intermediate layers or plies. Thus I may control the stratified or laminated structure of the web by disposing in the various cylinder vats such wet stocks with or without incorporated binder as will produce the desired web.

It will be understood that by "wet stocks" I mean a mixture of fibres or pulp fibres and,

cork in water. All such paper-making components are thoroughly mixed with water and put in suspension before being made into a felted sheet.

For example, the vats l0 may contain a stock composed of a mixture of cork and fibres while the end vats l I and i 2 will contain a stock which is exclusively fibres. Such a disposition may be reversed, and also each of the vats may contain a stock composed of a mixture of cork and fibres 75 or of fibres alone to produce the stratified web and the nature of the respective stocks can be varied to accord with-the ultimate product desired.

It will be understood that the web is built-up, i. e., simultaneously formed and bonded by'ielting to produce a substantially integral structure, characterized by the nature of the stocks fed to the respective cylinders. As I have here-.

inbefore set forth, webs which are not provided with a binder are resilient, cellular, and strong, but in accordance with the present invention, these inherent characteristics are materially enhanced. and more important, the web is rendered strongly resistant to tearing strains and bending and creasing strains.

In carrying out the invention, I prepare the various stocks and feed them to the cylinder vats. For example, I will prepare the stock consisting of a separator, that is, comminuted cork, fibres and sufilcient water, and feed such stock to the intermediate vats I 0; also I will prepare a stock composed substantially exclusively of paper fibres and feed the same to either of the end vats II and i2 to produce a surface layer or layers.

The broader phases of the process defined in the claims appearing hereinafter, may be carried out with the use of other separators than comminuted cork having substantially similar characteristics, for example comminuted barks other than cork, leather chips and rubber particles. By separators, I mean materials of low specific gravity which are compressible and/or elastic, which preferably can be screened to a size and which are of a character which retain compressibility and size when wet or compressed and which continue to separate the contiguous fibres and tend to cause these fibres to return to their original position when pressure has been released.

The separator or comminuted cork should be of a size which may be termed "effective. That is to say, the cork granules to be efiective should not exceed, in cross section, the desired thickness of the finished sheet, nor should they be smaller in cross-section than the cross-sectional diameter of the fibres. Finer cork than thiswill act as a filler, thereby preventing the formation of voids and air cells, and also will be lost to a larger extent in the paper making process; likewise smaller particles would be ineifective in acting as separators and. hinges about which the fibres can flex. I have used successfully cork particles of a grade from 50 to 150 mesh and 30 to 50 mesh.

The fibres with which the cork particles are mixed to form the web it, should be sufficiently long (a) to contribute tearing strength to the finished product, (b) to mesh and hold the separating particles, i. e., the cork, and (c) to make an absorbent paper, quickly permeable to saturating solutions. Specific examples of the fibres which I employ are:

Jute Absorbent alpha cellulose Rope Wood pulp fibres Hemp Cotton Sisal Linen Kraft pulp fibres Asbestos Long wood pulp fibres The requirements for a successful resinous binder are that it be capable of coating the cork particles and the fibres in such manner that the sheet will constitute a very strongly bonded structure in which the resilience and strength will be enhanced and the finished web will be substantially resistant to deformation.

Referring to Figure 1, I have illustrated a web constructed in accordance with this invention 5 and composed of a mixture of cork and fibres, and comprising a single layer or ply l3, for example as produced on the single Fourdrinier machine. A built-up structure of cork and fibre mixture is shown in Figure 3, the respective l strata ll of which are bonded together by the felting operation of the paper-making machine. The webs shown in Figures 1 and 3 will have the fibres and cork in intimate interlaced relation, producing a porous or absorbent structure capa- 16 ble of exerting capillary effect.

Either of the webs of Figures 1 and 3 will be permeated by a selected binder and most important, the density of the single ply or the density of the respective strata of the multi-ply '20 web may be controlled so as to regulate the amount of binder present when the web issubsequently saturated.

In the case of the stratified article, thethickness of the respective layers or plies it may be 25 regulated on the paper-making machine in accordance with the product desired by varying the number of cylinders employed, by varying the machine speed or the type of felt employed, and by changing other control factors which are well 30 known in the paper-making art.

In Figures 2 and 4, the paper-like layer I5 is composed exclusively of fibres and may be relatively thin with respect to the cork and fibre layers, as shown, and controlled as to density as heretofore explained if subsequent saturation is to be resorted to. The layers may be of any desired thickness and density equal to each other, or the fibre layer of greater thickness than the cork and fibre layer or different amounts of binder may be present in the different layers or different amounts of different binders may be i used in the various layers, all in accordance with the ultimate product desired.

The final webs obtained, that is, the single ply web or the composite web, will have the characteristics above enumerated, but will tend to crack or exhibit weakened areas if sharply flexed or creased. In other words, this product will have a tendency toward brittleness and will not pos- The binder creates a stronger union between the fibres and cork particles, increases the has the particular function or capacity of overcoming any tendency of the web to crack or weaken under creasing or folding strains. Also, ac-

cording to the specific requirements of the resultant saturated product, a binder can be selected which will render the product oilproof or waterproof or both, abrasion and wear resistant, and which will be harmonious with regard to a desired coating or finishing material.

The binder will uniformly coat the cork particles and impregnate the fibres throughout the cellular structure of the web and will be present in sufiicient amount to permanently insure and preserve a maximum of strength, resilience and flexibility in the web. a

strength and resilience of the respective webs and The binder employed will be described as a flexible binder but it will be understood that variations in stiffness or rigidity in the final product can be obtained by choosing a binder with the required characteristics, by varying the amount of the binder present and in some cases by varying the subsequent treatment of the binder. I For example, I may incorporate a large amount of a binder which when dried or cured throughout each of the layers of the integral web will produce a stiff sheet. Such sheet will have the characteristics of resilience and strength of the more flexible article and will be resistant to deformation in that it may be cut, punched, sawed or otherwise worked. The qualities in the final product are usually determined both by the choice of impregnant and by the amount of binder present and it should be understood that the control features of this invention include the use of different binders in different layers and which are controlled as to percentage or amount present.

The resinous binder and, in fact, any of the binders to be referred to hereinafter are incorporated in the sheet or in the stock from which the web is formed by either or all of the steps of immersion, pre-mixing, and beater addition and I find that the efficiency of the sheet material of this invention is due to obtaining a very thorough coating of the cork particles and fibres respectively with the binder.

Inorder that the operation of the invention may be clear, I will described several of the bindsuch as bituminous matter of asphalt pitches, that is bitumens which may be secured from the natural pitch lakes or as by-products from coke ovens, i. e., coal tar. I also use combinations of one or more of the several resins with a latex or vulcanized rubber mentioned in my copending application filed concurrently herewith, and as well as combinations of the said resins with animal and vegetable glues such as casein.

I also use as impregnating agents a etone solutions of vinylite resins, toluene solutions of polystyrol resins, alcohol and benzol solutions of phenolic resins, both with and without plasticizers, acetone solutions of alkyd resins both flexible and nonfiexible and naphtha solutions of oleo resin varnishes.

Since I also utilize with the resin binders, other hinders, the following additional examples of this component are described. In this connection, I may pre-mix a resin binder with one stock, and one of the binders to be mentioned with another stock and felt the same together on the paper making machine to produce the builtup layer having the respective laminations each provided with a different binder. Again, I may, by premixing or beater addition, incorporate a binder in the web which will be a resin binder and thereafter pass the web through a bath of one of the other types of binders to be now referred to.

with respect to the resinous binders above mentioned, I will use, for example, the flexible alkyd resins or bakeiite types (that is, phenolformaldehyde types) or other kinds of suitable resins available in the trade. It will usually be found advantageous to use both heat and the commonly indicated solvents for the type of resin employed in order to secure the proper degree of uidity for ready saturation in case the bath method is employed. The exact procedure lo will depend upon the method of impregnation product desired. Thus the permeated web may be subjected to both heat and pressure to cure the binder or to heat alone or to heat and oxygen (air) according to whether the permeating medium is heat reactive, oxygen reactive or both heat and oxygen reactive. Some saturants such as air drying varnishes or resins may be air cured at ordinary temperatures, but in general, higher temperatures with shorter curing times will be preferable. As illustrations of the above types, I prefer bakelite which is most advantageously cured with heat and under pressure, but which may be cured by heat alone; the modified alkyd resins as for example, the alkyd resins combined with China wood oil and suitable driers which are readily cured by heat and oxygen (air) and the so-called air drying varnishes with either natural or synthetic resins, which may be air-dried at ordinary temperatures.

Further examples of satisfactory flexible binders are natural or synthetic resins of which innumerable varieties are commercially available and which may be treated by conventional processes and with modifying agents as understood in the art, to impart the necessary flexibility and elastic characteristics.

These resins, plasticizers, and binders afi'ord the result that the sheet is strengthened, its tendency to crack or weaken is replaced by flexibility, resistance to sharp creasing and folding, and the compressibility and rebound not only are not disturbed, but are made eflective to a greater degree.

Examples of other binders are glutinous adhesives, such as casein, hide, bone, albuminous and similar glues capable of being rendered insoluble, and which can be treated or tanned, so as to become permanently and insolubly incorporated in the structure of the sheet.

As tanning agents, I resort to one or more of such materials as formaldehyde, paraformaldehyde, hexamethylenetetramine and sodium bichromate. In connection with the glutinous binder and tanning agent, I utilize plasticizers of which glycerine, sulphonated 'castor oil, diethylene glycol, and aquaresin, are examples. Thus I employ a plasticized adhesive or binder, and I find that with such a saturant the single ply or laminated structures are strengthened so as to be resistant to tearing, are rendered flexible, in that they will not crack under sharp creasing or folding and are pliable, in that regardless of the degree of flexing, to which they are subjected, they will return to the normal sheet-like condition without noticeable creases or any indication of the lines of bending. Moreover, such saturant being permanently and insolubly incorporated cure the rubber.

.throughout thecelluiar structure of the webs not only lends a resilience and pliability to the sheet, but enhances, to a remarkable degree, the inherent compressibility and rebound.

I also use as the binder a water solution or dispersion of normal latex having a content of rubber up to substantially 20% to 25% and to which solution is added sodium polysulphide in the amount of substantially 5% of the rubber present v and 1% to 2% of piperidine pentamethylene dithiocarbamate of the rubber present, as well as an antioxidant such as Neozone L (du Pont) in amountequivalent to substantially 2% of the rubber content. This composition is useful where an immersion treatment is employed. The impregnated sheet is dried at about 135 F. and subsequently heated to about 160 F. for about twenty minutes, to vulcanire the rubber.

Of the flexible plasticized adhesives above mentioned, it will be observed that many of them, such as the glutinous and resin binders are not only resistant to moisture. but are, moreover, inert with respect to various organic and inorganic solvents, of which mineral ofls and distillates are examples.

In selecting the various saturants or binders, the particular use of the material is the determining factor. In gasket materials it is essential that the article resist the action of water and oil so that it will not distintegrate when used to seal joints in pipes or containers conveying these fluids. In the manufacture of artificial leather, as well as floor coverings comparable with linoleum and artificial linoleum, it is essential, in most cases, that the article be moisture resistant.

The finished web when permeated with rubber latex or natural and synthetic resins, for exampie, will produce flexible floor coverings and artifieial leather not aflected by water.

In the manufacture of gasket material the tanned plasticized glue is very acceptable, and the product, while hygroscopic, will not disintegrate in water, and is very resistant to mineral oils and distillates.

With respect to binders adapted to produce stiflness in the sheet, I will use resins both natural and synthetic, rubber latex containing a high percent of sulphur and subsequently cured by a high degree of vulcanization, animal and vegetable glues with or without the hardening or setting agents to produce the required stiffness.

Where rubber is used as the permeating medium, I may employ vulcanized latex or vulcanized rubber which has been redispersed or vulcanized rubber dissolved in a suitable organic solvent. If a bath saturation process is used, the web can be saturated with rubber latex to which has been added sodium polysulphide or colloidal sulphur and a suitable antioxidant and the web subsequently dried at about 135 F.

A preferred solution for use as a bath saturant consists of normal latex containing 25% to rubber, 2% colloidal sulphur (based upon rubber present), 1% to 2% (based upon the content) of 'The sheet saturated with this solution may be dried at 135 F. and heated to about 160 F., to This solution produces a very flexible product. The flnal sheet may have a rubber content up to substantially 65% of the by heat, pressure, or both.

By reason of the pliability and resilience of the web, particularly with an incorporated binder such as described herein, it forms an excellent base for such plastic and flexible coatings as cellulose lacquers, or oleo resin varnishes, of which there are innumerable commercial varieties available. Such lacquers'utilize, as a base, a cellulose derivative, such as cellulose nitrate or cellulose acetate, together with a gum and plasticizer, and the present sheet material will cooperate with such a coating to prevent cracking of the coating film. I will also employ China wood oil varnishes and linseed oil varnishes which likewise are flex- 1 ible and of which a number of commercial varieties are obtainable.

Furthermore, substantially all of the binders will enable cellulose derivative or varnish coatings 5 and films to be applied to the sheet without difficulty.

' mixture, the binders, and examples of coating" In the case of artificial leather, I utilize coatings of pyroxylin, alkyd resins and similar substances which will produce the desired surface, and these, by reason of the flexible and resilient character of my laminated base, will be prevented from cracking or scarring in use.

In the manufacture of floor coverings, such as linoleum and artificial linoleum, I employ the varnishes and lacquers above mentioned, with equal success since the elastic and flexible nature of the coatings will be retained because of the flexibility and resilience of the laminated base.

I have set forth above the various components of the web, namely the fibres, the cork and fibre materials and finishes. 1

The method of carrying out the invention to produce the final binder incorporated sheet will now be described. I will have recourse to any one of three steps, and in some cases will combine one or more of these steps in accordance with the type of sheet desired.

In the drawing I have illustrated in Figure 8 a saturating treatment. That is to say, the web either formed on a single or multiple Fourdrinier machine, or upon a cylinder type machine, is entrained through the saturating bath as shown in Figure 8. l I

In this method, the density of ,the web will be controlled. and moreover its character will be determined by the nature and size of the cork, the nature of the fibres, and the amount of heating to which the mixture is subjected. Also the structure of the web will be regulated by the percentage of cork to fibre or' vice versa, and it will be understood that I may produce a web in which either of these components predominates.

Another step, and one equally preferable to the saturating treatment for incorporating the binder, is pre-mixing. By pre-mixing I mean incorporating the binder with the components of the stock before they are submitted to the beater action. In this manner not only may the structure or the web be controlled as above described, but also in the case of the stratified sheet, and percentage of binder and the type of binder may be controlled for the respective layers of the web.

the binder comprises beater addition. That is to say, the stock will have admixed with it in the beater the proper percentage and type of binder for the final article. 'It is to be observed that in each case I am enabled to control density of the web, the character of the components, their amount, i. e., their relative percentage with respect to each other, and the amount and character of the binder present in the final web.

With respect topre-mixing and beater addition, it will be understood that the components may be individually pre-mixed with the binder,

or a mixture of the components pre-mixed with of or after the web is formed. In other words,

I may resort to the single use of pre-mixing, beater addition, or subsequent bath saturation in order to impregnate the web with the hinder, or I may utilize a combination of any two or three of the above processes. As an illustration, I may add a binder by pro-mixing and add more of the same binder or another or a modifying agent in the beater or by subsequent immersion in the bath. In other words, independent consecutive treatments with the components of the saturant may be resorted to according to the binder employed and the specific qualities required in the resultant product.

Immersion treatment The web will be produced on the apparatus shown in Figure 7 or a multiple or single Fourdrinier. In the case of a single ply web of cork and fibres, its density will be controlled and the speed of travel through the bath regulated wherevary in inverse proportion to the density of the,

web and the speed of travel of the web.

In the case of the laminated integral and composite web, 1. e., built-up web, the same conditions apply except that the layers will usually be of different density and therefore less binder will be present in the layer or layers of greater density than in the one or more of less density, subject, of course, to the limitation that I could not efliciently in all cases introduce a high percentage of binder in the inside plies by the saturating process, where the outside plies are very dense, since these would present some difficulty to the introduction of the binder through them into the more absorbent inner plies. Therefore, in a final product of this kind, I preferably resort to beater addition or pre-mixing in order to introduce a high percentage of binder in the core and lower.

percentages in the outside plies. As an alternative, of course, I will resort to pre-mixing or heater addition to introduce the binder into the piles of the core and introduce the binder in the surface layers by an immersion treatment.

Specifically, and for purposes of illustration, since I have saturated webs of the various structures above set forth, (see (a) (b) (c) (d)) and have employed the various binders exemplified, the web will comprise a thin surface layer of fibres constituting a paper-like web and a layer' of cork and fibre mixture. The thin paper-like l resin in a to ammonia, a 25% ammoniacal cut shellac, a 40% urea formaldehyde syrup, bituminous emulsion, latex, a solution of rubber in benzol, or a saturating medium in which rubber is the disperse phase and water 16 is the continuous phase. In some cases it is found preferable to preheat the cork fibre paper in order to aid impregnation and in other cases it was found advisable to keep the impregnating material at approximately 60 C. during impreg- 20 nation. The respective proportions indicated may be departed from as desired and are simply given by way of illustration.

Also by way of illustration, I will treat similarly a single ply web of cork and fibres as herein described, the density of which has been suitably controlled.

The webs so treated are dried in any suitable manner, as on the drying rack or rolis as shown. The web is thereupon wound up into commercially distributable rolls. The final products are excellent for sealing material and gaskets, being resistant to mineral oils and water or other solvents, all according to the binder used.

The web treated by immersion, as just de scribed, has permanently and insolubly incorporated throughout its cellular structure, the flexible binder. This complete saturation is attained by reason of the interstitial nature of the web. That is to say, the presence of the separator, i. e.,

the cork particles, and their interlaced relation with the fibres, produces cells, air spaces and voids, whereby the web exerts a maximum capillary effect and the fibres are impregnated and the cork particles coated. In fact, both the fibres and cork are encased in the binder, and the thorough permeation of the web assures the presence uniformly throughout the web structure of sufficient binder to obtain and preserve the qualities of strength, resilience and flexibility or stiffness.

In the case of the stratifled web having a layer or layers l5 exclusively of fibres, i. e., a paperlike web, this thorough and uniform permeation is obtained, since such layers are porous in accordance with their density, permitting capillary action and the fibres are absorbent and capable of impregnation.

Any of the above mentioned binders may be used, as determined by the product desired, and prepared as a bath with their modifying agents,

through which the sheet is passed.

In this connection a single bath may be employed or several independent immerslons resortedto. Thus, in a laminated structure I may incorporate the glue and glycerine in one bath and paraformaldehyde in another, or place all in a single bath, with a suitable retardant, i. e., oxalic acid, to delay the glue formaldehyde reaction, to saturate the outside plies after a resin ous or rubber binder has been incorporated by pre-mixing or beater addition in the inside plies.

Further, the resinous and latex binders are capable of being cured in the sheet by means of heat and pressure or heat alone without producing any deleterious results. This is particularly 76 true with bakelite resins as well as the rubber saturants. and I have described above specific baths composed of these two materials. In some cases suitable dryers may be added to the varnishes or resins respectively, in order to decrease the temperature and time of curing.

Therefore, without describing them in detail, I refer to Figure 8 wherein the single ply or multiple ply web is passed through a single bath of a rubber or resin saturant and then through a curing and drying chamber over racks or rolls. The temperature of the chamber and the temperature and/or pressure of the rolls will be regulated in accordance with the particular saturant solution or mixture employed, according to its determined amount in the sheet and the setting or hardening required.

By way of illustration, since 'I use any of the structures mentioned above (see (a) (b) (c) ((1)) and the binders exemplified, in the impregnating method, the cylinder forming the top ply of paper is fed with a mixture of cork and fibre which has been subjected to a severe beating in order to decrease the porosity and subsequent absorption of this part of the web. The paper web is formed and dried in the usual manner and then passed through a bath containing a solution of a suitable resinous composition as described above to saturate the web and then passed to a suitable drying arrangement as shown to evaporate the solvent and cure the binder.

With respect to saturation with a bath of a rubber or resinous composition as herein described, the respective plies of the sheet will be controlled as to density, i. e., absorbency. As for instance, a more absorbent furnish may be supplied to the vats feeding the cylinders to form the surface ply or plies. The resulting web when subjected to the rubber or resin impregnating bath will absorb a higher percentage of rubber in the surface layer or layers than in the intermediate or concealed layers, thus furnishing resistance to wear at the point of contact when the product is in use.

In other words, the density of the outer layers would be so low, so as to permit the introduction of a high percentage of rubber in thb surface. The density of the inner or intermediate plies could be increased so that less rubber would be located in. the center section where it is not needed.

Thus by controlling the density of the outer layers, I increase the rate of absorption during the saturating process, so as to get a high percentage of rubber on the surface,

For wear resistant material, as fioor coverings, I select a resin or rubber saturant as above mentioned. These can be 'ured in the sheet to give a hard finish, and a sheet which will. be abrasion resistant and resistant to the action of water, mineral oils, as well as organicgand inorganic solvents. The amount present will be determined by the density of the web and the method of binder incorporation employed. Thus when wear resistant material is desired, it can be made by putting a high percentage of the selected binder in the top surface which can be accomplished by making the surface ply very absorbent if saturation is to be resorted to or by putting in a high percentage of binder in the top ply during the paper making process by beater addition or pre-mixing. In other words, I rely on density control to get the high percentage of binder on the top ply when saturation is employed whereas I preferably put the binder in during the paper-making process by pre-mixing or heater addition in most other instances to accomplish the result. As above explained, I e

ed to calendaring and/or hot pressing to produce also resort to a combination of both methods.

Pre-mixing By pre-mixing, the binder is mixed with th components of the web individually, as amixture or both, before being beaten.

In the case of'a single ply cork and fibre web, 10 the resinous or other binder is mixed (1) with the fibres, (2) with the cork, (3) with both, and (4) with a mixture of cork and fibre. The stock, i. e., mixture of structural components and binder, thereafter is beaten to the desired extent and 15 fed to the papermachine or respective vats for the cylinder. H

Where a paper-like layerforms a part of the web, it likewise is pro-mixed with" thebinder,

beaten and fed to theproper cylinder vats to 20 form, for example, an integral web having a paper-like layer of fibres and a layer of cork and fibre mixture.

Thus I form stocks of various components, regulate their density by the nature and percentage of the components and the beating action, control the percentage of binder present and the character of binder to form any of the sheets mentioned under (a), (b) and above by feedflow point of 70m 80 C., and 50 parts by weight of cork, 30 to 150 mesh. The entire mass is then mixed at a temperature of 90 C. for forty-five minutes. Hot water, 50 parts byweight, is added and the mixing continued for fifteen minutes, whence the entire mass is removed and placed in a suitable beater. The concentration in the beater is so adjusted as to givethe proper beating consistency, that is,a'pproximately 5% solids and beaten for one-half 'hour. The resulting furnish is then suitably diluted and used to feed the cylinder forming the surface ply in the final paperlike material. The other cylinders may be fed with a stock prepared as follows; 50 'parts by weight of rope fibre is saturated with an equal amount of water and placed in a steam jacketed mixer, together with 25 parts by weight of a phe nolic resin having a flow point of 70 to 80 C. and 50 parts by weight of cork, 30 to 150 mesh. The entire mass is then mixed at a temperature of 90 C. for forty-five minutes. Hot water, 50 parts by weight is added and the mixing continued for fifteen minutes, whence the entire mass is removed and placed in a suitable beater. The concentration in the beater is so adjusted as to give the proper beatingconsistency, that is, approximately5% solids, and beaten for one-half hour. The resulting furnish is then suitably diluted and used to feed the cylinders with the exception of 75 through the heated curing chamber maintained the cylinder forming the surface ply. The cyl inders fed, as described above, are operated to give a paper-like product with a surface layer.

at 125 C. in order to set up the binder. After the binder has been set, the web may be subjectthe desired finish.

An example of another resinous binder comprises fifty parts by weight of fiexible alkyd resin (A stage) prepared from the interaction of glycerine, phthalic anhydride and thefatty acids of linseed oil, is placed in a steam jacketed Werner Pfieiderer mixer, together with twenty parts of 50 mesh cork and 30 parts by weight of a mixture of equal parts of rope and jute fibre which has previously been saturated with an equal weight of water. The entire mass is mixed for thirty minutes at 85 C., whence more water is added to givea creamy consistency. The resulting dough is then transferred to a beater and beaten for an hour, then run on. a cylinder machine to give a paper of approximately .021" thickness. The resulting paper is then passed through the, heating chamber maintained at 130 C., to set the resin, a flexible waterproof, oilproof sheet being attained, which is a suitable base for the manufacture of artificial leather, fioor covering, and the like. ther forms of flexible alkyd resins known to the trade can, of course, be used. Natural resins, oleo binders, and bituminuous binders can also be used. As a specific example, forty parts by weight of a petroleum base asphalt, fiow point approximately 180 F., thirty parts by weight of 30 mesh cork and 30 parts by weight of suitable rag fibre,

are pre-mixed in a manner similar to that described above. The resulting mix, after proper dilution, is then beaten for a half hour in an ordinarybeater and made into 150 mil. board on a conventional board machine. The final board, after proper drying and heat calendering, produces a satisfactory insulating board.

In lieu of using different percentages of the samebinder in the stock invarious vats feeding the cylinders on a cylinder machine, we may use entirely different binders in the respective stocks supplied to the separate vats, since it is possible to prepare the stock for each vat by a separate pre-mixing and beater operation. As an example of this method of operation, a top or surface ply of papermay be formed in the same manner as given in the firstexample of the pre-mixing process. The other plies of paper may be made of a furnish prepared by pre-mixing and consisting of 40 parts by weight of petroleum base asphalt, flow point approximately 180 F., 30 parts by weight of 30 mesh cork and 30 parts by weight of suitable rag fibre. The resulting mix or furnish after proper dilutioniis then beaten for one-half hour in an ordinary beater and the respective stocks fed to the vats in the usual way.

In the manufacture of fioor coverings and the like, a low percentage of the binder may be placed in the cork fibre mixture used to feed the vats forming the center and, in some cases, the bottom layers, while a high percentage of a hard finishlng binder may be placed in the stock fed to the vats forming the surface layer so as to offer suflicient resistance to wear. Also where a high percentage of the hard binder is used in all the plies, then the material will be relatively stiff. Thus equal or different percentages of a similar hinder or a different one may be incorporated in the separate plies by the pre-mixture process.

It will be observed that by the pre-mix process I am able to have a relatively thin paper-like high or low density, and a layer of cork and fibremixture of greater or less density than the paper-like layer and containing a greater or less.

percentage of the binder. Furthermore, I will 5 incorporate any of the several binders above referred to, and in addition the concentration of the binder, that is, its adhesive effect, may be different for the respective layers.

Also, I Will use for some of the layers a binder capable of giving a hard finish, and I may incorporate in the respective layers different binders selected from those listed above, whereby .when the sheet is subjected to a curing action, one thereof will become hard and wear resistant while the other will be resilient.

By the pre-mix process I am enabled to produce flexible materials, absorbent materials, materials having a hard finish and abrasion resistance, and also I am enabled to produce a rela-v tively stiff product as where substantial or equal percentages of some of the binders, i. e., hard binders, permeate all layers of the composite web.

To obtain the proper adherence for a finishing 5 coating which may not be harmonious with the binder employed as an impregnating medium, the binder will be introduced by the pre-mix method in minimum quantities in the surface layer which is to come in contact with the coat- 3 ing material, while the inside layer or layers will have a higher percentage of binder present.

In this way a product is formed having high resistance to tear, but with absorbent surface layers. Such a product is of use for inner soles where some absorption of perspiration is desirable. Where heretofore it has been customary to produce a laminated article of this type by forming the layers individually and by bonding them by a rubber or other cement, the effect 40 has been that the cement between the respective preformed layers acts as a seal between the respective layers and prevents moisture from passing from one side to the other, which is corrected by the present process and article.

Beater addition With respect to beater addition, the same control is available as just described in connection with pre-mixing. The step of beater addition,

however, comprehends adding the binder to the beater mass or mixture, and is applicable with any of the binders above mentioned.

, Likewise, the curing treatments will be substantially the same, that is, the web will be formed from the respective stocks and thereafter presented to the curing chamber over racks or rolls and at appropriate temperatures and pres- .sures or both to obtain the desired setting of the binder.

With each process above outlined, the paper or board as formed is passed through a heated chamber over a drying rack or preferably rolls as shown in the drawing to remove the solvent or solvents. In cases where a heat convertible binder is present, the heat treatment is continued sufliciently to set the binder. In practically all cases a temperature of from 80 to 140 C. was found preferable, the time, of course, varying with the particular material.

Suitable coloring agents, for example, dyes or suspended pigments, may be added to the binders in order to obtain any desired color effects.

In connection with the examples given, other fibres will be used, as for example, rope, jute,

wood, kraft, sulphite, hemp, alpha cellulose, rag,

and the like; the proportion of fibre can be varied as desired.

Although 50 mesh cork was specified in the above examples, this can be varied over wide limits, and we have successfully used mesh ranges from 30 to 200.

In order to obtain a greater flexibility, more flexible phenolic resins than the examples given above can be used, or such plasticizers as for example dibutyl phthalate can be incorporated at the time of pre-mixing. Again, in the case of the phenolic binder, this can be varied over wide limits, as for example, from 20 to percent of the finished product.

By adjusting the proportions of binder with any of the methods described, a material suitable for use in the plastic field .can be prepared. However, in this case, the material is not given any severe heat treatment, care being taken that the paper is simply dried, in order that a subsequent molding operation can be carried out C., 1,000 lbs. pressure per squareinch).

It will be understood that the coating treatment will preferably take place after the binder incorporatedv web has been formed and the coating may be applied by immersion, brushing, spreading or spraying.

With each of the several methods, I am enabled to obtain a flexible product, and by varying the type and percentage of binder, and the curing treatment, one which will have relatively greater stiffness.

The specific natural and synthetic resinous binder compositions per se mentioned herein are all commercial products and I have set them forth as illustrative instances of binders which I have utilized with success. The same is true of the other binders and with the coating materials.

By resorting to pre-mixing and/or preferably beater addition, a product desirable for insoles can be formed which has high resistance to tear due to a high percentage of rubber or other binder in the inner layers but which has absorbent surface layers due to the decreased percentage of resin and/or rubber added to the beaters supplying the vats which make up these particular plies. For example, on the paper-making machine, I would produce by beater addition or pre-mixing a laminated sheet having a small percentage of rubber on the top layer which would insure the insole absorbency as required. I could not efliciently introduce a high percentage of rubber in the inside plies by the saturating process because where the outside plies were very dense, they would present some difficulty to the introduction of the binder through them into the more absorbent inner plies. Therefore, if the final product is to have absorbent outside plies and still contain the binders, I preferably resort to beater addition and make the completed product on the paper-making machine, so that its outside layers will contain less binder and therefore be more absorbent as to perspiration when used as inner soles, for example.

As modifications of the three methods which are embodied in the paper making process, I may subject the respective stocks or any one of them to a pre-mixing or beater addition treatment and thereafter to a saturating treatment using different types of the binders herein mentioned.

Summing up the control features of the invention and regardless of the components, the control of the qualities of the finished sheet are secured byfirst, the regulation of the density of the individual layers, second, by the control of the percentage and type of binder present in the layers. and third, by the combination of these two I H controli'eatures. The density of a layer oi paper v composed of plain fibre or or cork and fibre or any other components from which the paper will be made, .can.be varied in the paper-making process (without the introduction 01' a binder'oi 1 any kind) by. varying the time of beating, length of fibre, size of cork particles and relative pro-- portions of these or other components employed.

A multiple ply paper made on a cylinder papermaking machine can therefore be made by laminating several plies of paper having a diflerent density in each ply. when this completedsheet issaturated, the amount of saturant which the various plies will absorb will be diii'erent, d8.- pending upon the varying rates of absorption resulting from the variation in density from ply toply, subject to the practical limitationsheretofore disclosed. That is, for example, a large amountof binder cannot be introduced into a.

porous center ply if the. outside plies are of greater density. Therefore, a means of controlling the amount of hinder or saturant present inthe dif- 2 ferent pliesis presented by the density control of the individualplies, although as in the illustration just given, no binder is introduced into the plies during the paper-making process.

resorted to, I not only vary the amount of binder present in the individual plies but vary as well the type of binder or binders in the individual layers. For example, I use diflerent amounts of the same binder in vats ll- -i0 and can use different percentages, oi. an'entirely different binder in vats Ill-42. The binder is incorporated in the paper-making process eitherby pre-mixing or beater addition or both,

As a third variation, Ican have a combination of the cases just outlined above whereby'I control the densityof one or more piles of paper (unimpregnated) and combine these plies on the paper-,makingfmachine with other plies contain- 5 ing controlled amountsof binder or binders, added ent in the individual plies or layers when such hinder or binders are added by the pre-mixing and/or beater addition processes, and

3rd; By thecombinationof these two methods.

It will be understood that the coating treatment will preferably take place after the binder incorporated web has been formed and the coating may be applied by immersion, brushing, To spreading or spraying.

With each of the several methods I-am enabled to obtain a flexible product, and by varying the type andpercentage of binder and the curing treatment, one which will have relatively greater stiffness.

' Wherepre-n'iixing and/or beater addition are by pre-mixing or beater addition or both. This: productis then passed from the paper-making 1st. That, presented as in the bath treatmentf Wa led he t. ,4

ss a e tively stifi, as desired, serving as a reinforce- 75 m ans-m ment for the web and may be permeable or im- The preformed material will be (see Figure (1) a backing, (2) a facing, and (3) both, or (see Figure 6) a core. As to the 5 core structure, this also may have a facing or backing, or both, of the preformed material.

That is to say, the sheets will be constructed in accordance with either of the webs of Figures 1 to 4. The combining may take place on any 10 suitable combining machine, as for example, be-

tween opposed rolls.

A preformed facing and backing material is applied as the permeated webs issue from the paper making machine or bath and the combining takes place simultaneously with the curing of binder and the drying of the web, 1. e., the combining rolls will be suitably heated.

The adhesive may be applied to the surface of the preformed material or the surface of the web.

Pressure or heat sensitive adhesives are employed as well as glues and binders of the type recited above. In certain cases the web will have excess binder present on its surface so that additional adhesive will not be required. Again the web and preformed non-permeated material will be combined and then the composite sheet saturated in a bath of the binders herein described. Also the permeated or nonpermeated webs may be formed and wound into rolls, and thereafter combined with preformed material as required, or the compervious.

bining will be a continuous or consecutive step after or before permeation or after or before drying of the web. Also, the combining may be accomplished with pre-cut sheets as with the manufacture of veneers.

These faced and backed products have a variety of uses and particularly are useful for printing press blankets, insoles and rug anchors, as well as floor coverings. They may be suitably coated for any desired purpose with lacquers or varnishes as herein described.

For press blankets I may use any of the permeated webs herein described, but I prefer to use for printing press blanket material a single or double ply web of cork and fibre in accordance with this invention. I saturate the web with one of the natural or synthetic resinous materials or with a glutinous adhesive, 1. e., glue and glycerine and set the glue with formaldehyde. This will give a flexible blanket of required strength and resilience.

I will in some cases, where added strength is needed, apply a flexible backing of paper, cloth or vulcanized fibre. Also I apply the backing to both surfaces of the web as shown in Figure 5 as a further reinforcement. 1

As a modification, a non-permeated web of cork and fibre has one or both surfaces united to a backing as above described.

As a further modification a core of the backing material will be employed such as cloth or paper and the webs united to opposite sides thereof. A backing and/or facing will also be used in some cases.

Asa further form of printers blanket or make ready, and particularly with reference to the use of vulcanized fibre, I will employ! relatively thin sheet of this material, and adhesively unite it to one of the sheeted products of this application, or

to a layer wholly of comminuted cork particles and a binder, preferably one of those herein mentioned.

This material (i. e., cork and binder) may be sheet-,

ed or may be spread upon the vulcanized fibre sheet.

The outside surfaces of the blanket material will be treated in such manner as to be smooth and impervious and non-adhesive to printing ink.

For insole material I will use any of the various webs herein described and any of the several binders to obtain a flexible, strong and absorbent material which likewise is resilient.

Preferably the exposed portion or tread surface will be freely absorbent to perspiration and hence will have only a minimum of binder present.

A permeable facing or backing such as muslin or other open web fabric will sometimes be applied to one or both surfaces of the web as a reinforcement.

The undersurface will also in some cases carry a pressure sensitive or heat sensitive adhesive of which many varieties are commercially available.

The insoles will be stamped out of the sheet in the usual manner.

As one illustration, I will, by pre-mixing or heater addition, put a small percentage of binder such as a resin and/or rubber latex in the top plies (fibre alone or cork and fibre) in order to produce absorbency of the finished insole on account of perspiration. In the intermediate and bottom plies, I introduce a high percentage of a binder such as a resin and/or rubber latex in order to increase the strength of the product, its resistance to wear and ability to stand sewing.

Other of the binders are equally applicable.

A new and important use for treated cork fibre- (single ply or multi-ply) resides in its application as a rug anchor. Tests with a sheet of cork fibre impregnated with a resinous material as well as with glue, glycerine and formaldehyde under small rugs on polished floors were very satisfactory. The rug does not slip on the cork fibre surface and the cork fibre grips the polished floor so that there is no movement of the rug relative to the cork fibre or the cork fibre relative to the floor, or both the cork fibre and the rug relative to the floor.

Cork fibre treated with the various binders mentioned produces a very acceptable rug anchor with or without the addition of a reinforcing material such as a layer of paper or cloth. This expedient is used in some cases in order to prolong the life of the anchor because small rugs are constantly being removed from the floor for cleaning purposes, and in the handling, a thin sheet of cork fibre might ultimately become torn. I use a combination of cork fibre and cloth, and cement the cloth on the side of the cork fibre which is in contact with the bottom side of the rug. I also put two layers of cork fibre on either side of a core of reinforcing cloth. I also use a rubber-like binder in some cases.

The products of this invention, especially treated cork and fibre, are adapted for use as anti-squeak material on automobiles. In this application, the compressibility and resilience of the product insure a tight joint between the adjacent surfaces and at the same time due to sound absorbency prevent noise and squeaking. It is readily processed into the desired form, that is, cut, slit, or folded. It is also substantially weatherproof and does not disintegrate when wet.

Another automotive application is the-use as window channel material. The compressibility and resilience of the cork and fibre products make possible a tight joint with glass and at the same time afford a yielding or cushioning support to prevent window breakage. Other desirable attributes for this purpose are availability in various colors, weatherproofness, resistance to disintegration when wet, sound absorbency and ease of processing.

It will be understood that the various structures set forth herein will be permeated with various of the binders, for example, the surface layer will be permeated with a glutinous binder, i. e., glue, glyeerine and formaldehyde, and the intermediate plies and bottom plies with a resinous material or a rubber-like material. Thus also one layer will contain a rubber-like binder and another layer a'resinous binder. Similarly other sheets will be formed in which either the resinous binder or the rubber-like binder will permeate the surface layers and the other binders the intermediate and bottom layers. In some cases the top and bottom layers will be permeated with the same binder.

In referring herein to a resinous binder, I mean various natural and synthetic resins and compo- 20 sitions thereof which are well-known commercial articles, and in connection with rubber-like materials, I mean latex and similar latices, i. e., balata and gutta percha and various rubber compositions, all of which are available in the trade.

The term paper-like is intended to cover the webs produced in accordance with this invention on a paper-making machine.

I claim:-

1. The process of making sheet material com- 30 prising a laminated web having paper-like layers felted to produce an integral composite structure which comprises preparing separate stocks for the individual layers, felting the layers on a paper making machine into an integral laminated web,

and including a different resinous binder material in predetermined percentages in each respective layer.

2. The process of making sheet material comprising a laminated web having paper-like layers felted to produce an integral composite structure which comprises preparing separate stocks of' different densities, each of a mixture of separator and fibres, felting the stocks on a paper making machine into an integral web, the laminae of which have different coefiicients of absorbency and saturating the web with a resinous binder to include such binder in the web in accordance with the absorbency of the layers thereof.

3. The process of making sheet material comprising a laminated web having paper-like layers felted to produce an integral-composite structure which comprises preparing separate stocks of difierent densities, each of a mixture of comminuted cork and fibres, felting the stocks on a paper making machine into an integral web, the laminae of which have different coefficients of absorbency and saturating the web with a resinous binder to include such binder in the web in accordance with the absorbency of the layers thereof.

4. The process of making sheet material comprising a laminated web having paper-like layers felted to produce an integral composite structure which comprises preparing separate stocks for the individual layers, incorporating in some of said stockspredetermined percentages of a resinous binder material, felting the stocks into a laminated web and saturating the web to incorporate a binder material in other of the layers of the web.

5. Sheet material comprising a laminated paper-like web having the laminae thereof felted binder. l

'7. Integrally laminated sheet material of paperlike form having one of its layers permeated with a resinous binder and another with a glutinous adhesive.

8. Integrally laminated sheet material of paperlike form having one of its layers permeated with a resinous binder, and another with a rubberlike binder and another with a glutinous adhesive.

ELMER, C SCHACH'I.

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