US2826522A - Wall board product and method of manufacturing same - Google Patents

Description

March 11, 1958 w. c. 'M'ATTSON WALL BOARD PRODUCT AND METHOD OF MANUFACTURING SAME Filed Nov. 27, 1953 o v k w m m m M E V C. N N R R T T A A L H. w. m% Y B 3% 22m M6565 55E .io Su E3210 mwuE 596 2: 2:; $23 02.5.. v 9:5 5!: 5:5 zmwmom z M355 5:5:

WALL BQARD PRODUCT AND METHOD OF MANUFACTURING SAME Willard C. l lattson, Ashland, Oreg.

Application November 27, 1953, Serial No. 394,730

i Claims. (Cl. 154-459) This invention relates to wall board and a method of manufacturing it, particularly wall board having a medium density. By medium density is meant board with a density of between .5 and 1.0.

The utilization of waste products of the lumber industry has been the object of a great deal of investigation, particularly during recent years because of the rapid depletion of our lumber resources. There have been many suggestions for the use of this Waste including the manufacturing of building materials such as wall board and the like from the waste.

It is the object of the present invention to utilize lumber waste products and manufacture them into wall board which has some of the characteristics of natural wood yet has certain advantages thereover including being less expensive than a comparable grade of natural wood.

Briefly, the process according to this invention comprises the following steps: Feeding wood shavings or chips into a hammer mill where the particles of wood are reduced to 'a more or less common size; screening the particles from the hammer mill and retaining the particles of desired dimensions; drying these particles until they have a desired moisture content, mixing the particles with a binder solution; depositing the mixture in a blanket form on belts, cutting the blanket of material into a plurality of sections of given length and placing them in a press where they are subjected to a certain amount of heat and pressure for a fixed time. After the pressing operation, the boards are completed and need only be trimmed to pre-determined size.

The Wall board produced according to this invention has many uses such as wall panelling, sheathing, subfloors, veneer stock. The physical properties of the product are such that is will not warp or split and it will ignite only when subject to intense heat. The board in its natural state is water repellent and may be treated or covered to make it waterproof, however, such processes or products form no part of the present invention and it is intended that the board produced according to the invention will be primarily for use other than that which is exposed to the elements or much moisture. The board will not absorb and disperse a liquid throughout its body if exposed thereto the way a blotter does. For instance, if a portion of this board is permitted to stand in water for some time, only that portion actually in contact with the water will absorb the water, and the rest of the board will remain dry. The board is resistant to denting, scratching or other marring, yet can be painted, have veneers applied thereto, paper, plaster or other covering materials. The wall board has good insulating characteristics and may be sawn and have nails or screws applied thereto the same as lumber. The board may be made up in standard 2' x 4' and 4 x 8 panels, having thicknesses of from /2 to A. The dimensions of these boards may, of course, be varied on special order.

Referring to the flow diagram, shavings from a planar States Patent 2,826,522 Patented Mar. 1958 mill and chips from a chipper are accumulated in a suitable storage from which they are fed into a hammer mill. The hammer mill is set so that it will beat this material into wood particles, having about the following dimensions: length, to /4; width, ,1 to A2"; thickness, $4 to The particles from the hammer mill are conveyed to screens which sift out substantially all particles which do not have the previously mentioned dimensions. It has been found that it is permissible to have between 5 and 10% by weight of particles which vary in dimensions from those previously mentioned. If the percentage of the diiferent sized particles is greater than 10%, it has been found that the ultimate boards are lacking in some of the desirable qualities of this product, i. e. strength, beauty. Pieces of bark may also be permitted to go into the hammer mill where they are pounded fine and it is permissible to have from 1% to 3% by weight of bark in the final board. The main function of the bark in the board is to give color which when used in correct amounts heightens the eye and sales appeal of the board.

After the screening step, the particles are dried so as to have a moisture content of from 2% to 5%. The dried particles are then conveyed into a mixer where they are sprayed with a mixture comprising by Weight 2% to 4% phenolic resin, 2% to 4% of wood or ethyl alcohol, and 3% to 5% of petrolatum. If it is desired to diminish the amount of time that the particles are subjected to the pressing operation hereinafter described, 2% to 4% of glycerine may be added to liquefy the resin. The use of glycerine also reduces the fire hazard and necessity for ventilating equipment required when alcohol is used alone in the mixture.

After the particles and the formula have been thoroughly mixed, they are carried to a felter which deposits them in the form of a continuous sheet or blanket on belts. The blanket may conveniently have a Width of about 4 feet and if it is desired to make Vt inch Wall board, for instance, the blanket will have a thickness of about 5 inches. The belts carry the blanket past flying cut-off saws which cut it transversely into sections of desired length such as 8 feet. The blanket sections are then placed one above the other 10 to 30 at a time in a charger or a loader which loads them into a press. It has been found that the appearance of the end product may be enhanced by subjecting the surfaces of the blanket sections to a light spray of water just before pressing. In the press, the sections are subjected to a heat of around 275 F. plate temperature and 300 to 325 pounds pressure p. s. i. The heat may vary up to 5% from the 275 F. temperature. The length of time which the sections remain in the press depends on the thickness of the ultimate board, and in the case of a /2 inch board, for example, the sections will be left in the press between 8 to 12 minutes. If glycerine has been used in the mixture, the pressing time may be cut down to 5 to 7 minutes.

After the pressing operation, the completed sections of wall board are placed on a loader which carries them to trim saws which remove ragged edges and cut the board into any final desired dimensions.

All of the machinery employed in this process is commercially available and well known to people familiar with operations in saw mills and hard board or plywood manufacturing plants.

While a preferred embodiment of the invention has been described, alternatives, variations and certain changes will be suggested to those skilled in the art by the foregoing. However, it is the intention to cover all such changes and to limit the invention only as defined in the appended claims.

I claim:

1. A wall board comprising comrninuted woo-d particles of pre-deterrnined sizes, and a binder for holding the particles together comprising by weight 2% .to 4% Phenolic resin, 2% .to 4% glycerine, 3% to 5% petrolaturn.

2. A cured wall board comprising comminuted wood particles substantially all of which are A" to /4" in length, ,5 to A3" in width, A to in thickness and a binder for holding the particles together comprising about 2% to 4% phenoli resin, about 2% to 4% glycerine and about 3% to 5% petrolatum by weight.

3. The method of forming wall board comprising the steps of comminuting pieces of wood into particles having substantially the following dimensions: length, As to A1", width A to 4;", thickness ,4, to 12, screening the particles to retain those of desired dimensions; drying the particles to have a moisture content of about 5%; mixing the particles with 2% to 4% phenolic resin, 2% to 4% glycerine, 2% to 4% alcohol, 3% to 5% petro'latum; forming the particles into flat sections; subjecting the surface of the sections to a light spray of water; subjecting said sections to a pressing operation at about 275 F. and 300 to 325 pounds pressure p. s. i. until the sections are formed into Wall board; and trimming the board to predetermined dimensions.

4. The method of forming medium density /2 inch cured wall board comprising the steps of assembling Wood chips and shavings, comminuting said pieces of Wood into particles to retain substantially all of the particles whose dimensions are about in length, 34 in width, in thickness; drying the particles until their moisture content is about 5%; placing said particles in a mixer; mixing said particles with a formula comprising by weight about 2% thermosetting phenolic resin, 2% alcohol, 2% glycerine, 5% petrolatum; forming the particles in a continuous blanket of about 5 inch thickness; cutting the blanket transversely into sections of desired length; subjecting the surfaces of the sections to a light spray of water; placing a plurality of said sections one on top of another in a press; subjecting the sections to a pressing operation at about 275 F. and 300 pounds pressure p. s. i. for about 7 minutes; removing the sections from the press and trimming the sections into wall board panels of desired dimensions.

References Cited in the file of this patent UNITED STATES PATENTS 1,901,325 Novotny Mar. 14, 1933 2,067,012 Loetscher Jan. 5, 1937 2,078,269 Nevin Apr. 27, 1937 2,080,078 Mason et al. May 11, 1937 2,122,543 Toms'icek et al. July 5, 1938 2,642,371 Fahrni June 16, 1953 2,658,847 MacDonald Nov. 10, 1953 FOREIGN PATENTS 608,252 Great Britain Sept. 13, 1948

Claims (1)

1. 4. THE METHOD OF FOMING MEDIUM DENSITY 1/2 INCH CURED WALL BOARD COMPRISING THE STEP OF ASSEMBLING WOOD CHIPS AND SHAVINGS, COMMINUTING SAID PIECES OF WOOD INTO PARTICLES TO RETAIN SUBSTANTIALLY ALL OF THE PARTICLES WHOSE DIMENSIONS ARE ABOUT 1/8" IN LENGTH, 1/16" IN WIDTH, 1/64" IN THICKNESS, DRYING THE PARTICLES UNTIL THEIR MOISTURE CONTENT IS ABOUT 5%, PLACING SAID PARTICLES IN A MIXER, MIXING SAID PARTICLES WITH A FORMULA COMPRISING BY WEIGHT ABOUT 2% THERMOSETTING PHENOLIC RESIN, 2% ALCOHOL, 2% GLYCERINE, 5% PETROLATUM, FORMING THE PARTICLES IN A CONTINOUS BLANKET O F ABOUT 5 INCH THICKNESS, CUTTING THE BLANKET TRANSVERSELY INTO SECTIONS OF DESIRED LENGTH, SUBJECTING THE SURFACES OF THE SECTIONS TO A LIGHT SPARY OF WATER, PLACING A PLURALITY OF SAID SECTIONS ONE ON TOP OF ANOTHER IN A PRESS, SUBJECTING THE SECTIONS TO A PRESSING OPERATION AT ABOUT 275*F. AND 300 POUNDS PRESSURE P.S.I. FOR ABOUT 7 MINUTES, REMOVING THE SECTIONS FROM THE PRESS AND TRIMMING THE SECTIONS INTO WALL BOARDS PANELS OF DESIRED DIMENSIONS.

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