US2425719A - Manufacture of linoleum - Google Patents

Description

A118. J. L BERGER 2,425,719

MANUFACTURE OF LINOLEUM Filed Sept. 19, 1942 Patented Aug. 19, 1947 MANUFACTURE OF LINOLEUM John L. Berger, Columbia, Pa., assignor to- Armstrong Cork Company, Lancaster, Pa., a corporation of Pennsylvania Application September 19, 1942, Serial No. 458,947

This invention relates to the manufacture of linoleum and, more particularly, to the production of molded inlaid linoleum and the like in which the pattern is formed essentially of inlays initially of granulated inlaying composition compacted into a homogenous mass onto a suitable backing such as burlap or waterproofed felt and subsequently cured.

Molded inlaying composition is generally formed of oxidized oil and resin, intimately mixed with a filler such as cork or wood flour and suitable pigments. The particles or granules of inlaying composition are sticky in the sense that if a handful of the mix is compressed, it will ball or cohere. The mix is, however, when in its loose condition, suificiently free flowing to permit strickling through small stencil openings.

In the manufacture of molded inlaid linoleum, a backing of burlap is fed over an inlaying table under a series of stencils and granulated inlaying composition is strickled through the stencils onto the backing indesign, each stencil serving to define the outline of an inlaid area. of a separate color. As the material moves through the machine past the complete set of stencils, the entire surface of the backing is covered with inlaying composition. The composition is in a relatively loose condition and is subsequently subjected to heat and high pressure, in the neighborhood of 350 F. and 1450 pounds per square inch, to consolidate it into a wear resisting surface of the desired final thickness, properly keyed to the burlap or other foundation. Heated platen hydraulic presses are generally used for this purpose.

In the pressing operation, considerable difliculty has been occasioned due to the adherence of the granulated inlaying composition to the platen of the hydraulic press which engages it in initial heat consolidation. If the adhesion is great, whole areas of the inlaying composition will be pulled away from the backing and other areas will be loosened from the backing. Even when there is only slight adherence over the whole face of the composition, the parting of the press platens causes a loosening of the inlaying composition from the backing and a poor key results in the finished product.

One method commonly used with considerable success and obviating to some extent at least the problem involved has been the use of a web of oiled paper applied over the upper platen of the first press. A fresh portion of the oiled paper is presented at each pressing operation. Whilethis precludes sticking of the composition to the press 9 Claims. (Cl. 154-26) platen, it has been objectionable for a number of other reasons primary, among which is the fact that even with oiled paper there is a slight adherence of the inlaying composition onto the oiled paper under the high pressure and temperature conditions'of consolidation so that when the oiled paper is stripped from the face of the composition, a thin film or skin of composition is pulled from the face of the compacted mass and this reduces the smoothness of the upper surface and also tends to pull the composition away from the backing, loosening the key. Besides, the paper is relatively expensive and can be used but a. single time.

Another method which has been tried without any substantial success is to spray the loose granular inlaying composition with a mist of lubricant. This was done immediately prior to initial consolidation. This practice was unsuccessful primarily because the lubricant prevented proper binding of the granulated mix into a homogeneous mass. The binder and the lubricant are not compatible and, since the mass is relatively open and porous, the application of a spray of lubricant to the surface has resulted in penetration of the lubricant through a substantial portion of the thickness of the layer of inlaying composition and this has reduced the internal bond of the particles to the depth of penetration of the lubricant.

Theapplication of an oil film to the face of the upper platen of the press has been tried but the problems of uniform distribution of a lubricant to the face of a large heated platen hydraulic press are manifold and this method has never been commercially practiced.

According to this invention, the upper surface only of the loose granulated inlaying composition is coated with a lubricant prior to initial consolidation of the mass. Thus, the application of the lubricant is limited to-those surfaces of the particles which will be engaged by the pressing surface. This is preferably accomplished by engaging the loose inlaying composition with a web of fabric,such as muslin or scrim cloth, which has been saturated with a lubricant. Only a'relatively slight pressure is applied, sufficient to [insure engagement between the lubricant-saturated fabric and the upper surface of the particles, but insuificient to cause particles of the linoleum composition to adhere to the fabric. An extremely thin film of lubricant is transferred to the upper surface of the particles at the face of the inlays.

It is not necessary that heat be applied at this stage and it is preferred not to apply heat until initial consolidation is eifected. Since the movement of the material through the inlaying machine is intermittent, the lubricant is preferably applied by an intermittently operating device.

In order that the invention may be more clearly understood, reference will be made to the accompanying drawing in which:

Figure 1 is a diagrammatic view showing an apparatus in conventional form for carrying out the method of this invention; and

Figure 2 is a diagrammatic view of a modified consolidating press utilized in carrying out a modification of my method.

Referring to the drawing, the forward end of a molded inlaying machine is shown. This includes the usual table 3 and pin band conveyor 4. The conveyor is intermittently operated to draw the backing through the machine into the various stencilling stations. The material as it emerges from the inlaying machine, as shown in Figure l, is formed of a backing 5, shown diagrammatically as a single line, having a layer 6 of granulated inlaying composition thereon, preferably formed of inlays of different colors, although the material may be monocolored or of the granite type having two or more colors randomly interspersed.

In regular manufacture, the material passes from the inlaying machine to a press 1 where initial heat consolidation is effected. The upper platen 8 of the consolidating press 1 is normally covered with an oiled paper to prevent adhesion, as previously pointed out. According to this invention, there is disposed between the initial heat consolidating press 1 and the point where the stencilling and inlaying is completed a device 9 for applying lubricant to the upper surface of the particles forming the layer 6 of inlaid composition. In the embodiment diagrammatically illustrated, this takes the form of a plate I having a fiat lower surface over which is stretched a fabric such as muslin or scrim cloth H, saturated with a suitable lubricant. Parafiine oil is the preferred lubricant, but other lubricants may be substituted for it. The fabric is fed from a wind-up roll l2, over the plate ID to a wind-up roll IS. A hand crank I4 is shown by which the winding may be conveniently effected. Generally, a fresh area is presented at each step to insure a uniform application of the lubricant to the surface and when the fabric has all been reeled onto the wind-up l3, the roll is resaturated with the lubricant and the operation of the wind-ups is reversed, the roll l2 now serving as a wind-up. A hand crank I5 is provided on the wind-up roll l2 for this purpose.

To bring the lubricant-saturated fabric into engagement with the upper surface of the particles, there is shown for purposes of illustration a cam l6 engageable with a cam follower ll mounted upon a support for the plate I0. The operation of the cam I6 is synchronized with the movement of the pin conveyor 4 to bring the device 9 down into engagement with the composition 6 at each stencilling operation'and while the material is at rest on the inlaying table 3.

No substantial pressure is applied by the device 9; sufficient is applied to insure a satisfactory transfer of lubricant from the fabric II to the surface of the composition 6 uniformly over the whole treated area. Satisfactory results have been obtained when the pressure has been limited to about one and one-half pounds per square inch but this will vary depending upon the type of lubricant employed, the physical make-up of the 4 fabric, and the tackiness of the inlaying composition being operated upon, The lubricant should be of such nature and transferred in such amount that the surface only of the particles forming the upper surface of the layer is coated, but this coating should be complete to prevent adherence of untreated particles to the platen 8 in initial heat consolidation.

The material with lubricant applied to the upper surface is then heat consolidated and cured in the usual manner. My method finds particular usefulness in the high temperature-low pressure initial consolidation and a final low temperature-high pressure facing or finishing consolidation. This method is diagrammatically illustrated in Figure 1 where press 1 has the upper platen 8 and the lower platen [8 each heated to about 350 F. A pressure of about pounds per square inch is applied for a period of about six seconds with a typical linoleum mix. The web attains a temperature of about 280 F. during this initial consolidation. The composition is reduced in thickness and consolidated to some extent and the high temperature causes the binder for the composition to flow to a considerable extent. The pressing surface is highly polished and is preferably a chromium plated steel platen. Even with this high temperature treatment, there is no offsetting or sticking of the composition to the press platen 8. As previously pointed out, it has been customary practice to cover the press platen 8 with a web of oiled paper to prevent this adherence and the disadvantages of such practice have been stated above. With my method this is completely eliminated.

The consolidated material then passes to a facing press [9 having an upper platen 2U heated to about 240 F. The lower platen 2| is heated by conduction from the heat in the composition and normally attains a temperature of about 180 F. A heated plate 22 may be interposed between the presses I and 19 to maintain the desired temperature in the composition, about 230 F. The facing press applies a pressure of about 1450 pounds per square inch to the composition, reducing it to final thickness, giving it a high gloss face, and keying it securely to the backing. The dwell of the facing press 19 is about six seconds and the consolidated web maintains its temperature at about 230 F. during this pressing operation.

The finally consolidated material is fed to a curing stove or oven for maturing in the customary manner.

In Figure 2, I have illustrated a press of modifled construction for the initial heat consolidation. It will be noted that the forward end 23 of the upper platen 24 of the press is flared at 25. It is customary to provide the lower platen 26 with a pad of cushioning material which is similarly flared as shown at 21. The purpose of this is to provide gradually reduced pressure to the material to avoid any sharp line of demarcation where adjacent areas are pressed.

Employing my method, eliminating the use of oiled paper over the upper platen of the press, I have found that there may be some tendency with certain types of linoleum mix for the particles to adhere to the flared portion 25 of the upper press platen 24 since, in consolidating presses as ordinarily constructed, the whole press platen is heated to a high temperature and insufficient pressure is applied to the particles at the flared portion to consolidate and join them pressing or tend to build up with other particles on the nose of the press. I have found that this may be overcome by providing cooling coils in the nose of the press as shown by the dotted lines 28 in Figure 2. These may be in theform of passageways or conduits through which brine, cold water,-or other cooling medium may be passed. Since there is some conduction of heat from the main portion 4 of the platen to the end portion 23, there will be a gradual reduction in temperature from the point where the nose 23 joins the main platen 24 outwardly toward the lip of the press. I prefer to maintain a temperaturebelow about 160 F. in the nose for at such temperature there is no lifting of particles. i

From the foregoing, it will be understood that by this invention I eliminate the need for the application of oiled paper or other facings to the initial or final consolidating presses and provide an arrangement whereby the lubricant maybe applied directly to the upper surface only of the particles to be engaged by the pressing surface in the initial heat consolidation. The carrier for the lubricant may be reused indefinitely and there is no offsetting or picking up of particles of composition or stripping off of a skin of material as is common when oiled paper is used under the initial consolidating press.

While I have illustrated and described certain preferred embodiments of my invention, it will be understood that my method is not limited to the embodiment shown and described but may be otherwise embodied and practiced within the scope of the following claims.

I claim:

1. In the manufacture of molded inlaid linoleum and the like, the steps of bringing a flat surface carrying a lubricant into engagement with a loose mass of granulated composition to transfer a film of said lubricant to the upper surface only of the mass of the composition, said lubricant being applied prior to initial heat consolidation, moving said composition to an initial consolidation station and there applying heat and pressure to said composition with the lubricated surface of said granules in direct contact with the pressing surface.

2. In the manufacture of inlaid linoleum and the like, the steps of bringing a surface coated with a lubricant into engagement with an unconsolidated mass-of granulated composition under pressure sufficient to transfer a thin film of said lubricant to the uppersurface only of the mass and insufiicient to cause said particles to adhere to the lubricant coated pressing surface and thereafter applying heat and pressure to said granules with the lubricated surface of the granules in direct contact with the pressing surface to efiect initial heat consolidation of said composition.

3. In the manufacture of molded inlaid linoleum and the like from a loose mass of granulated composition, the steps of pressing a flat, unheated surface carrying a lubricant into engagement with a mass of loose granulated composition to transfer a film of said lubricant to the upper surface only of the mass of composition, said lubricant being applied prior to initial heat consolidation, and thereafter applying heat in the order of 350 F. and pressure to said granules to effect initial heat consolidation of the granules with the lubricated surface of said granules in direct contact with the pressing surface with the applied lubricant serving as the sole means for preventing adhesion between the granules and the heated pressing surface.

4. In the manufacture of molded inlaid linoleum and the like from a, loose mass of granulated inlaying composition, the steps of bringing apressing surface coated with a lubricant from above a layer of granulated inlaying composition deposited upon a. backing into engagement with the upper surface only of said layer to transfer a small amount of lubricant to the loose particles disposed at the upper surface of said layer, said lubricant being applied prior to initial heat consolidation, elevating said pressing surface away from said layer, and thereafter applying heat and pressure to said granules with the lubricated surface of said granules in direct contact with the heated pressing surface to effect initial heat consolidation of the inlaying composition into a homogeneous wearing layer. I

5. In the manufacture of molded inlaid linoleum and the like from a loose mass of granulated composition applied to a backing, the steps of intermittentlyapplying a, lubricant to the upper surface only of particles of granulated composition disposed on said backing, said lubricant being applied priorto initial heat consolidation, and

intermittently applying heat and pressure to the mass of granulated composition disposed on the backing to effect initial heat consolidation, with the area under consolidation lying contiguous to an unconsolidated but lubricated area to be subsequently consolidated, said heat and pressure being applied substantially uniformly throughout the extent of the area under consolidation, except in a narrow zone adjacent the contiguous, lubricated area to be subsequently consolidated Where a force is applied gradually diminishing from that applied to the major area and where the granules are heated to a lesser degree.

6. In the manufacture of molded inlai linoleum and the like from a loose mass of granules of linoleum composition having a heat sensitive oilresin binder, said granules being disposed upon a backing web in the form of an unconsolidated layer, the steps of intermittently applying lubri cant to the upper surface only of the particles of granulated linoleum composition to be engaged by a pressing surface, said lubricant being applied prior to initial heat consolidation, intermittently moving said web with the lubricated granules to an initial heat consolidation station and there applying pressure to said lubricated granules with a flat heated pressing surface, said heat and pressur being applied substantially uniformly throughout the extent of the area under consolidation except in a narrow zone adjacent anunconsolidated portion of the layer where a force is applied gradually diminishing from that applied in the major area and where the granules are heated to a lesser degree, and thereafter consolidating the granules in said narrow zone with the application of greater heat and higher pressure than initially applied in said zone,

'7. In the manufacture of molded inlaid linoleum and the like from a loose-mass of granulated composition, the steps of pressing a fiat foraminous surface wetted with a lubricant into engagement with a mass of loose granulated composition to transfer a film of said lubricant to the upper surface only of the mass of composition, said lubricant being applied prior to initial heat consolidation, and thereafter applying heat and pressure to said granules with the lubricated surface of the granules in direct contact with the pressing surface to effect initia1 heat consolidation of said composition.

8. In the manufacture of molded inlaid linoleum and the like from a loose mass of granulated composition, the steps of pressing a flat surface carrying paraffine oil into engagement with a mass of loose granulated composition to transfer a film of said parafiine oil to the upper surface only of the mass of composition, said paraffine oil being applied prior to initial heat consolidation, and thereafter applying heat and pressure to said granules with the paraffine coated granules in direct contact with the pressing surface to effect initial heat consolidation of said composition.

9. In the manufacture of molded inlaid linoleum and the like from a loose mass of granulated REFERENCES CITED The following references are of record in the file of this patent:

UNITED .STATES PATENTS Number Name Date 425,875 Godfrey et a1 Apr. 15, 1890 1,305,127 Lawson May 27, 1919 1,850,630 Kaufman Mar. 22, 1932 2,299,066 Berger Oct. 20, 1942 308,508 McFerran Nov. 25, 1884

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