US2686143A

US2686143A - Process for manufacturing a composite wooden board

Info

Publication number: US2686143A
Application number: US630619A
Authority: US
Inventors: Fahrni Fred
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-04-25
Filing date: 1945-11-24
Publication date: 1954-08-10
Anticipated expiration: 1971-08-10

Description

F. FAHRNI Aug. 10, 1954 I PROCESS FOR MANUFACTURING A COMPOSITE WOODEN BOARD Filed Nov. 24, 1945 3&1

* INVENTOR. Em e/{ .BY 77041.4

Patented Aug. 10, 1954 OFFICE 2,686,143 PROCESS FOR MANUFACTURING A COM- POSITE WOOD EN BOARD Fred Fahrni, Zurich, Switzerland Application November 24, 1945,

Serial No. 630,619

In Germany April 25, 1942 Section 1, Public Law Patent expires 11 Claims.

The object of the present invention is a process for the manufacturing of fabricated sheets or compound compressed plates made of layers of pieces of wood and binding materials.

The products so far known of this type, made of wood pieces and the like mixed with a binding substance, showed great disadvantages.

When the pieces of wood were of coarser splinter shaped material, the surface is too rough and unsuitable for many uses, as for instance for flooring, cabinet-makers work and so on.

Where a finer material is used, which necessitated a larger amount of binding substances, such plates are too expensive, all the more when coarser pieces of wood are used and reduced to a finer material, which necessitates a larger use of energy.

In addition compressed masses of fine material alone with water content of 8% and over, when compressed hot, presented difficulties, because the steam could not escape and steam bubbles spoiled the production.

This disadvantage can be obviated by placing a metal sieve or the like between the heated press and the mass to be compressed, which however on the other hand makes it impossible to produce plates smooth on both sides, since a sieve mark on one of the sides prevents it.

These difficulties have now been overcome by the process according to the present invention by superimposing at first a basic layer of fine, selected material, then a middle layer of coarser material, needing less binding substance, and finally a covering layer of fine, selected material the mass so obtained being then compressed in one operation.

A major advantage of this process is that due to the presence of the said middle layer, relatively coarse Wood waste of any shape, colour and size without any great additional use of materials for binding may be used for making compound compressed good looking wood plates.

The plate has, nevertheless, as a result of the special basic and covering layers, a perfectly fine and equal surface, so that its uses are almost endless.

The porous structure of the coarser inner layer serves simultaneously as a channel for steam so that on both sides smooth plates are obtained.

More beautiful and smoother surfaces are obtained by keeping the outer layers damper than the inner ones during the compression, so that the general development of steam is relatively slight. Thus warping of the plates will be avoided.

It is further advantageous to add larger quan- 690, August 8, 1946 April 25, 1962 titles of binding material and of substances ensuring a better appearance and resistance to outside influences to the pieces of wood destined for the outer layers. Such substances consist for instance of waterproofing or additions to achieve a greater resistance to humidity, to harden the pieces of wood, to add colours to the same or for heightening of the powers of resistance against mildew and mold and so on. Thereby, in spite of a great reduction of production costs, the whole surface of the outer surface is particularly good and firm.

The accompanying drawing shows a sectional view of what a fabricated sheet or plate, made according to the present invention, may look like, and illustrates a partial and half schematical embodiment of a device, given by way of example, for the manufacture of wood plates according to the present process.

Fig. 1 is the said sectional view.

Fig. 2 shows how the three layers may be filled into frames.

Fig. 3 is a detailed view of the filling apparatus for the finer material, forming the basic and covering layers.

Fig. 4 is a detail of the of the coarser material.

In the plate shown in cross section in Fig. 1 the two outer layers, of finer material, I, 2 with mirror smooth upper surface 3 or i, are immeiately recognizable, as also the middle layer 5 of coarser material.

The size of such a plate is, of course, limited only by the possibility of compressing bigger upper surfaces.

The three layers can, by means of a very Simple apparatus according to Fig. 2, be superimposed.

On a bed or guide 6 frames can be moved or conveyed to and fro or lengthwise.

Such a frame is shown in i.

It first performs a to and fro movement according to the arrows 8 between the extreme positions 1 and la, and this under a filling funnel, which serves to lay the fine basic layer.

Figure 3, further described below, gives more details of such a funnel.

The Whole layout must of course so be conceived that an equally distributed layer results.

This first operation terminated, the frame is pushed to R where it, by means of the arrows Iii, is moved to and fro between the positions It and 70. A channel H, which can be constructed, for example, as a shaking channel serves to feed the middle layer, made of coarser maapparatus for the filling terial, on to the basic layer already in the frame.

After termination of this second operation the frame is pushed further towards 5d, where it again, according to to the arrows l2, carries out a to and fro movement.

A funnel it serves, thereby, like the funnel 9, to lay the upper covering layer of fine material.

Finally the triple layered mass will be subjected to the compressing operation.

Now will be shown shortly according to Fig. 3, how the filling of the basic or covering layer may be carried out.

The frame l is here shown in the shape of a form closed at the lower side in reality, however, it is executed as a movable frame of which the lower side consists of a sheet of polished metal.

Its to and fro movement, according to arrows 8, arises with the help of an endless chain l5 propelled. over two rollers like 14, with a pin ll, reaching into the lower fork H; of the frame.

If the roller li turns in the direction of the arrow, it is easy to see that the pin, lying on the upper part of the chain, first propels the frame to the left.

If it, however, arrives over the roller, it will slide downwards in the fork i6 and the desired turning of the carrying direction is obtained. This operation will take place in the same manner to the right, outside the drawing, in crossing the roller, not shown, opposite roller i l, but in the opposing direction.

In the upper part of the funnel 9 there is a slider it, on which can be laid the finer material it, which is first prepared and in some cases, weighed.

Under this slider rotates a spur-cylinder so in the direction of the arrow 2 i. It breaks up possible lumps in the material that it feeds out of the slider 58 to a number of cylinders 22 closely continguous to each other and square in profile,

which distribute this material evenly over the shaking sieve 23.

The sieve, thrust to and fro by the lever 24, can accomplish about 80 complete movements to the minute, and the cylinders 22, driven over strap 25, about the same number of rotations to the minute, while the spur cylinder 20, for example, turns ten to twelve times slower.

The evenly distributed fine material falls into the frame 1 through the lower part of funnel 2%.

The channel l l, the upper part of which is visible in Fig. l, for coarser material, can be fed for example with the help of a bucket-chain 2'! raising the material in question out of a pit.

Finally, the second funnel i3 would be constructed something like the first, that is to say according to the execution according to Fig. 3.

Of course the briefly described contrivances can be completed by further apparatus, as for example automatic weighing devices and the whole process could be run partly by hand, partly or completely automatically.

It should now be added that it is expedient that, when the outer layers are of a markedly finer material than the inner, these latter should be compressed before the finer layers are filled. By the pre-compressing of the coarser inner layers the projection of parts into the outer surface will be avoided and further the space between the single coarser pieces will be reduced, so that complete covering may be carried out with a minimum of covering material.

The mixture, composed of pieces of wood and binding substances, placed in the frame, can next, be compressed in the said frame and then without frame submitted to the main compression. This has the advantage that the press serving for the main compression, which is usually a hot press, need not be constrained, either in its measurements or its execution to limits defined by the shape of the frames, whereby its uses are considerably increased.

Following are some examples of execution of the process according to the present invention:

Example 1.-Waste from veneering, ends, and furniture factories are so worked in a splitting machine that pieces result between 5 and 50 mm. long, about 5 to 10 mm. wide and from one to several millimeters thick. Other shorter and thicker little pieces occurring do not matter. This material is, possibly previously waterproofed with 2.5% paraffine, dried to a humidity content of 5% and with a 3.5% of a binding substance, for instance a condensate of urea-formaldehyde obtained in powder form according to an already known process with the suitable catalyst, which rapidly dissolves the binding substance in question in the heat and then mixed with water.

For the covering layers the material is dustfree, clean white soft wood, planing shavings or other thin and flat kinds of shavings, which are mixed with 14% of binding substances and finally kept to a humidity content of 1 3% by sprinkling with water.

In a mobile form having a sheet-metal base like l of Figs. 2 and 3, so many thin layers are formed through the to and fro movement, that these are, when finally compressed, 2 mm. thick. On this basic layer are again spread so many single layers of as much previously selected coarser material as to produce when compressed, a thickness of 21 mm.

These two layers can in some cases be precompressed and thereover single layers of glued flat shavings of the same mixture will be filled in up to 2 mm., in order to produce the covering layer.

The whole mixture will now be rapidly precompressed, so that it becomes sufficiently coherent and provided with a covering sheet of metal, be compressed without frame in, for instance, a press heated to 120 C. with 10 kg. pressure per square cm.

The product obtained is a beautiful, firm and on both sides very smooth plate with a pale, veneer-like surface, which is very suitable for furniture or cabinet-making, for doors as for walls and ceiling coverings. The covering layers may also be stained. and polished and thus substituted for expensive veneering.

Example 2.Uneven waste, such as sawmill waste, splinters, trunk disks, etc., are broken into coarser, splinter shaped parts and dried to about 4%. 800 parts by weight of this material are mixed, according to the already known process, with 32 parts by weight of a binding substance, fed uniformly into a form as described under (1) and pro-compressed; this accounts to about 4% of binder.

Uneven waste of hard wood is split on a suitable machine into thin, fiat, planing shavings shaped pieces of wood, which are then further reduced to scale shaped bits. After drying out to 10% humidity content 150 parts by weight as well as 50 parts by weight finer hard wood saw shavings are mixed with 20 parts by weight of a waterproof binding substance and 20 parts by weight of water. 10 parts by weight of hard wax powder are then added. The mass thus mixed layers of the sheet into one body.

What I claim is:

l. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material; applying 3.5% of a binder substance to said coarse wood pieces so as to obtain slightly humid binder treated coarse wood pieces; cutting other wood material to substantially flat shavings; applying 14% of a binder substance to said fiat wood shavings so as to obtain humid binder treated fiat wood shavings; forming a first humid surface layer of said humid binder treated fiat wood shavings; superimposing on said first surface layer a slightly humid porous core layer of said slight- 1y humid binder treated coarse Wood pieces; superimposing upon said porous core layer a second humid surface layer of said humid binder treated fiat wood shavings; and applying a pressure of substantially 1O kilogram per square cm. at a temperature of substantially 120 C. to said superimposed layers so as to cause a firm adhesion of said binder treated fiat wood shavings in said surface layers and of said binder treated coarse wood pieces in said porous core layer to one another and to cause also a firm adhesion of the layers themselves to one another, while permitting the steam formed by applying heat to escape into said porous core layer of coarse wood pieces, thereby obtaining a composite wooden board composed of a porous core layer and two substantially water-impervious surface layers firmly adhering to said porous core layer and having a high tensile strength.

2. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material; ap plying 4% of a binder substance to said coarse wood pieces so as to obtain slightly humid binder treated coarse wood pieces; cutting other wood material to substantially fiat shavings; applying of a binder substance to said flat wood shavings so as to obtain humid binder treated fiat Wood shavings; forming a first humid surface layer of said humid binder treated fiat wood shavings; superimposing on said first surface layer a slightly humid core layer of said slightly humid binder treated coarse wood pieces, said core layer having a porous structure forming air channels; superimposing upon said porous core layer a second humid surface layer of said humid binder treated flat wood shavings; and applying a pressure of substantially 25 kilogram per square cm. at a temperature of substantially 150 C. to said superimposed layers so as to cause a firm adhesion of said binder treated fiat wood shavings in said surface layers and of said binder treated coarse wood pieces in said porous core layer to one another and to cause also a firm adhesion of the layers themselves to one another, while permitting the steam formed by applying heat to escape into said air chamiels in said porous core fiat wood shavings; superimposing .6 layer, thereby obtaining a composite wooden board composed of a porous core layer and two substantially water-impervious surface layers firmly adhering to said porous core layer and having a high tensile strength.

3. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material; drying said coarse wood pieces to a humidity of approximately 5%; applying 3.5% of a binder substance to said coarse wood pieces so as to obtain binder treated coarse wood pieces; cutting other wood material to substantially fiat shavings; applying 14% of a binder substance to said fiat wood shavings so as to obtain binder treated flat wood shavings; keeping said fiat wood shavings at a humidity of approximately 18%; forming a core layer of said binder treated coarse wood pieces; forming a surface layer of said binder treated fiat wood shavings; superimposing said core layer and said surface layer upon each other; and applying pressure to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated flat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervious to water and having a high tensile strength and firmly adhering to said porous core layer.

4. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material; drying said coarse wood pieces to a humidity of approximately 5%; applying 3.5% of a binder substance to said coarse Wood pieces so as to obtain binder treated coarse wood pieces; cutting other wood material to substantially fiat shavings; applying 14% of a binder substance to said flat wood shavings so as to obtain binder treated fiat wood shavings; keeping said fiat wood shavings at a humidity of approximately 18%; forming a core layer of said binder treated coarse wood pieces; forming a surface layer of said binder treated said core layer and said surface layer upon each other; and applying a pressure of substantially 10 kilogram per square cm. at a temperature of substantially C. to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated flat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervious to water and having a high tensile strength and firmly adhering to said porous core layer.

5. A process of manufacturing a composite Wooden board, comprising the steps of making coarse wood pieces from a wooden material said wood pieces having substantially a length between 5 and 50 mm., a width between 5 and 10 mm., and a thickness of at least 1 mm. drying said coarse wood pieces to a humidity of approximately 5% applying 3.5% of a binder substance to said coarse wood pieces so as to obtain binder treated coarse Wood pieces; cutting other wood material to substantially fiat shavings; applying 14% of a binder substance to said fiat wood shavings so as to obtain binder treated fiat wood shavings; keeping said fiat wood shavings at a humidity of approximately 18%; forming a core layer of said binder treated coarse wood pieces; forming a surface layer of said binder treated fiat wood shavings ;-superimposing-said core layer and said surface layer upon each other; and applying a pressure of substantially 10 kilogram per square cm. at a temperature of substantially 120 C. to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated fiat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervicue to water and having a high tensile strength and firmly adhering to said porous core layer.

6. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material; drying said coarse wood pieces to a humidity of ap proximately 4%; applying a relatively small quantity of a binder substance to said coarse wood ieces; cutting other wood material to substantially fiat shavings; applying a relatively large quantity of a binder substance to said flat wood shavings so as to obtain binder treated flat wood shavings; keeping said flat wood shavings at a humidity of approximately 18%; forming a core layer of said binder treated coarse wood pieces;

forming a surface layer of said binder treated flat wood shavings; superimposing said core layer and said surface layer upon each other; and applying pressure to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated fiat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervious to water and having a high tensile strength and firmly adhering to said porous core layer.

7. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material; drying said coarse wood pieces to a humidity of approximately i%; applying 4% of a binder substance to said coarse wood pieces; cutting other wood material to substantially flat shavings; applying 10% of a binder substance to said fiat wood shavings so as to obtain binder treated fiat wood shavings; keeping said flat wood shavings at a humidity of approximately 18%; forming a core layer of said binder treated coarse wood pieces; forming a surface layer of said binder treated flat wood shavings; superimposing core layer and said surface layer upon each other; and applying pressure to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated fiat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervious to water and having a high tensile strength and firmly adhering to said porous core layer.

3. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material said wood pieces having substantially a length between 5 and 50 mm, a width between 5 and and a thickness or at least 1 mm.; drying said coarse wood pieces to a humidity of approximately 4%; applying a relatively small quantity of a binder substance to said coarse wood pieces, cutting other wood material to substantially flat shavings; applying a relatively large quantity of a binder substance to said flat wood shavings so as to obtain binder treated fiat wood shavings; keeping said flat wood shavings at a humidity of approximately 18%; forming a core layer of said said binder treated coarse wood pieces; forming a surface layer of said binder treated fiat wood shavings; superimposing said core layer and said surface layer upon each other; and applying pressure to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated fiat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervious to water and having a high tensile strength and firmly adhering to said porous core layer.

9. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material said wood pieces having substantially a length between 5 and 50 min, a width between 5 and 10 mm, and a thickness of at least 1 mm.; drying said coarse wood pieces to a humidity of approximately 4%; applying 4% of a binder substance to said coarse wood pieces; cutting other wood material to substantially flat shavings; applying 10% of a binder substance to said flat wood shavings so as to obtain binder treated flat wood shavings; keeping said flat wood shavings at a humidity of approximately 18%; forming a core layer of said binder treated coarse wood pieces; forming a core layer of said binder treated coarse wood pieces; forming a surface layer of said binder treated fiat wood shavings; superimposing said core layer and said surface layer upon each other; and applying pressure to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated flat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervious to water and having a high tensile strength and firmly adhering to said porous core layer.

10. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material; drying said coarse wood pieces to a humidity of approximately 4%; applying 4% of a binder substance to said coarse wood pieces; cutting other wood material to substantially flat shavings; applying 10 of a binder substance to said flat wood shavings so as to obtain binder treated flat wood shavings; keeping said fiat wood shavings at a humidity of approximately 18%; forming a core layer of said binder treated coarse wood pieces; forming a surface layer of said binder treated fiat wood shavings; superimposing said core layer and said surface layer upon each other; and applying a pressure of substantially 25 kilogram per square cm. at a temperature of substantially C. to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated flat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervious to water and having a high tensile strength and firmly adhering to said porous core layer.

11. A process of manufacturing a composite wooden board, comprising the steps of making coarse wood pieces from a wooden material said wood pieces having substantially a length between 5 and 50 mm., a width between 5 and 10 mm, and a thickness of at least 1 mm.; drying said coarse wood pieces to a humidity of approximately 4% applying 4% of a binder substance to said coarse wood pieces; cutting other wood material to substantially flat shavings; applying 10% of a binder substance to said flat wood shavings so as to obtain binder treated fiat wood shavings; keeping said fiat wood shavings at a humidity of approximately 18%; forming a core layer of said binder treated coarse wood pieces; forming a surface layer of said binder treated fiat wood shavings; superimposing said core layer and said surface layer upon each other; and applying a pressure of substantially 25 kilogram per square cm. at a temperature of substantially 150 C. to said superimposed layers so as to cause firm adhesion of said binder treated coarse wood pieces and said binder treated flat wood shavings to one another, thereby obtaining a composite wooden board composed of a porous core layer and a surface layer being substantially impervious to water and having a high tensile strength and firmly adhering to said porous core layer.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,033,411 Carson Mar. 10, 1 36 2,066,734 Loetscher Jan. 5, 1937 2,067,012 Loetscher Jan. 5, 1937 2,078,269 Nevin Apr. 27, 1937 2,080,078 Mason May 11, 1937 2,120,137 Mason June 7, 1938 2,124,921 Lederer July 26, 1938 2,347,697 Levey May 2, 1944

Claims

1. A PROCESS OF MANUFACTURING A COMPOSITE WOODEN BOARD, COMPRISING THE STEPS OF MAKING COARSE WOOD PIECES FROM A WOODEN MATERIAL; APPLYING 3.5% OF A BINDER SUBSTANCE TO SAID COARSE WOOD PIECES SO AS TO OBTAIN SLIGHTLY HUMID BINDER TREATED COARSE WOOD PIECES; CUTTING OTHER WOOD MATERIAL TO SUBSTANTIALLY FLAT SHAVINGS; APPLYING 14% OF A BINDER SUBSTANCE TO SAID FLAT WOOD SHAVINGS SO AS TO OBTAIN HUMID BINDER TREATED FLAT WOOD SHAVINGS; FORMING A FIRST HUMID SURFACE LAYER OF SAID HUMID BINDER TREATED FLAT WOOD SHAVINGS; SUPERIMPOSING ON SAID FIRST SURFACE LAYER A SLIGHTLY HUMID POROUS CORE LAYER OF SAID SLIGHTLY HUMID BINDER TREATED COARSE WOOD PIECES; SUPERIMPOSING UPON SAID POROUS CORE LAYER A SECOND HUMID SURFACE LAYER OF SAID HUMID BINDER TREATED FLAT WOOD SHAVINGS; AND APPLYING A PRESSURE OF SUBSTANTIALLY 10 KILOGRAM PER SQUARE CM. AT A TEMPERATURE OF SUBSTANTIALLY 120* C. TO SAID SUPERIMPOSED LAYERS SO AS TO CAUSE A FIRM ADHESION OF SAID BINDER TREATED FLAT WOOD SHAVINGS IN SAID SURFACE LAYERS AND OF SAID BINDER TREATED COARSE WOOD PIECES IN SAID POROUS CORE LAYER TO ONE ANOTHER AND TO CAUSE ALSO A FIRM ADHESION OF THE LAYERS THEMSELVES TO ONE ANOTHER, WHILE PERMITTING THE STEAM FORMED BY APPLYING HEAT TO ESCAPE INTO SAID POROUS CORE LAYER OF COARSE WOOD PIECES, THEREBY OBTAINING A COMPOSITE WOODEN BOARD COMPOSED OF A POROUS CORE LAYER AND TWO SUBSTANTIALLY WATER-IMPERVIOUS SURFACE LAYERS FIRMLY ADHERING TO SAID POROUS CORE LAYER AND HAVING A HIGH TENSILE STRENGTH.