US2143831A - Synthetic products and process for making them - Google Patents

Description

Patented Jan. 10, 1939 UN TE osjTATES sYnTnitTrcrRo UcrsANn rltooss'sron l l V ,George H.Ellis,St.'Paul,and wiuismm-scmarge,

Minn

eapolis,,Minn., assignors to The Insulite Company, Minneapolis, Minn.,a corporation o! Minnesota 1N0 Drawing. Application jahuaiye, 1932,

Serial No.5 84,56 6

bla m (01.192421) "I'his inventlonrelates generally to the synthetic production of; hard, stifl, board-like bodies and particularly ,toa processior producingib'odies of high tensile strength-which are highly non- 5 water absorbent, and which have asmall*-'coefllcient of expansion in the presence of moisture. Objects are: to produce bodies 'of the above character, cheaply from ,flberized wood or the like; to produce bodies which-have'an unusual 1o tensile strength; generally to bind the woody or fibrous constituents together by the usefof vegetable substances other than woodycons'tituents; and specifically to produce such, bodies by mixing pulpedwood, or" the like, either separatelyi of in combination with the follo'wing vegetable substancesz tung'oil; perilla oil, soybeanloil, corn oil or linseed oil; formingasheet and then-simultaneously applyingfheat and pres'surex Therefore; where the body was composed substantially only or rawfood, it wasynecessary "(in order to obtain proper cementationl that the mass being pressed have a high water content, which content was depended uponflto obtain cementation and hardness, and to facilitate reduction of volurne;under action of'pressure and heat. We havefound, however, that synthetic wood "products having a substantially greater tensile strength than any known tons," and also having a substantially greater water-proofness, can be obtained by using, in admiirture withthe fiberized material, the substances named. ,We have alsofound that by'using such substances, avery'thoro ugh andstrong cementation of'the fibers can be accomplished in thepresence of a verysmallquantity of-water. The discovery of the results obtained by the use of the substanceabove mentioned. in'the presence of a small amount of watenis" of great value, partly 40 because of the superior strength and toughness of: the products, and partly because it j is 'on'ly necessary to dispose of a relatively small quantity of water during thepressing operation;

Thepresent invention is based on at" least four discoveriesi the first of which relates to" the action of the oils mentioned (andprobably other oils of the same class) when added to wood pulp or "like iiberize d vegetable matter; the second tothe efiect of the application of i pressure and heat to a sheet formed from such In carryin out" claimed, procesa w or processes, "to produtzeJthe. claimedl product, or

' products, asuitahle' 'fiberiz able substance (such as woodfincluding poplar, Spruce, jack pine or U any sawmill waste or forest waste), is fiberized, Y

jforeicample, bythe grindstone process toproduce fc'oarsa longjfibers such. asare commonly used in the ffmanufacture of heat [insulating bodies. Qrdinarily; the fiber is toolongand too coarse for fthe-coarsest grades, oipapeniandsthus a pulp 10 ,ir u'ch cheape flth'antheordinary pulp is produced.

In order to obtainja very thigh, degree .or cementation of "the fibers, after formation, into a sheet (under the action of heat and pressure) 15 ariclf resultanthi h ite isile strength and hard- "ness, andlwater-Droofn'ess in the finished product, emulsions j of one er: more of l the following vegetablefsubstances are added to thepulp be made into a sheet: tung oil, perilla 20 oil, soybea'noilfcorn oillorihnseed oil.

'As'an e ramplei Whentung oil is used, take an amount 2 f oilby weightequalto ten percent Emulsifythis oil, preparing the emulsion asiol- 25 lows: Use an amount ofwater in weightequal t the weight ofthe on, and add to the water a weight of sodaash within a range of one to two per centot the weight of. thewoill Add the, soda-ash water, slowly to the oil, while 30 rapidly agitating. j

an example: When soybean ,oil is used, take an amountiofpil equal ,to ten per. cent of the dry" weight, of the finished product. Emulsify and prepare theemulsion as follows; Usegal ten 35 per cent water solutionof rosinfsize equal' to weight offthesoilfijadd "this solution slowly to the oiL while rapidly agitating. The oil can be added directly to the pulp, but much more time is required to ,distributefthe oileven1y over 40 the fibers. 1

i i The aboye procedures, relating to amounts of oil' 'andfthe rnan ner of, emulsifying, have given excellentfresults; 'However, l good [products are: obtained by adding quantities of Chinaewood oil 45 (tung oili orlsoybeanfoil-in quantities, by weight ranging 'froni'iiye td thirtyfper cent, and by the additiori' tofthis oil" of j rosin size in quantities from" one toflve per cent of the weight of the oil. l

The emulsion is added to the pulp and thoroughly mixed therewith. Then alum is added to break down the emulsion. The pulp is now run into and through a suitable apparatus such as a cylinder felting machine (of the type shown in is porous sheet, and for this purpose a. steam heated hydraulic press is generally used. Oneside'oi' the press generally-has a smooth polished plate Patent Nb. 1,672,249 to George H. Ellisfor Apparatus for making composition boards or sheets) to produce a wet sheet approximatelyone-hali an inch thick. The sheet is delivered to a drying oven, which has a temperature of about 350? Fahrenheit at one .endand about 250 Fahrenheit at the other. Ninety-five per cent or more of the water is removed. The dry board can -thanten. The product is completed by. the simultaneous:

then be stored, and it may absorb moisture from the atmosphere (depending on the degree of.

humidity) enough water to raise the moisture content above five, but not substantially more application of heat and pressure to the thick The sheet is pressed at pressures ranging from 300 to 600 pounds per square inoh,with the temperature of the press ranging from" 300 to. 5009 Fahrenheit, the temperature depending upon the time that the'sheet is to remain in the press, and

"upon the hardness, tensile strength, toughness quired. Two of thebestproducts are those which contain ten percent of ftung oil or ten nd degree of resistance to watereabsorption-reper cent of soybean oil, and in which-the sheet is submitted to a pressure of 500 pounds per square inch at a temperature of I400v Fahrenheit, with the pressure and temperature applied for about vforty minutes. A very good board is produced by pressing for ilfteenl minutes at 409 pounds at 37 5'.

Fahrenheit.

It has been discovered that by adding from one to four per cent of montan wax (obtained'from the lignite by steam distillation) or ozok erite wax "(a fossil wait), paraflln wax, beeswax or rosin size to the tung oil before it is emulsified, or by adding from one to four per cent of coal-tar creosote,

that the water absorbing ability of the finished board is'reduced, without introducing. any objectionable qualities. The weight of added was is one to four. per centof, the weight of'the dry finished product. 1

The product'resultant from the of tung-oil has a .very high tensile strength and is unusually tough. The product resultant from the use of "soybean oil has also a high tensilestrensth, and although not quite as tough as that produced from the tung oil, it can be more cheaply produced.

The tensile strength of the product is great estin direction of movement of the sheet din-ingfabrication, that is. perpendicularly to the axis of rotation of the forming cylinder.

It has been found thatthe tensile strength decreases if the rosin is in greater amount'thanoil. Good proportions have been found to be six of, oil-four of rosin; seven of oilthree of rosirn A board-made from coarse raw wood fiber, which is one-half an inch thick when Impressed, vand containing about ten per cent of oil has a-tensile' strength of aboutQOO poundspersquareinch and a water absorption-of thirtyper cent, after suba,14a,ss1.

per cent, after submergence for two hours. The increased thickness of this pressed board (at the end of the period of submergence mentioned) is only about .008 of an inch.

It appears that, because of the presence of the oil in the thick sponge-like dry board, before and during the process of dry pressing. the oil acts to soften and make the fiber more plastic. We have discovered that the hardening of the all takes place very rapidly at high temperatures and very slowly at low temperatures; for example at a temperature 01300" Fahrenheit, hardening of the .oil requires about three hours; at 450 Fahrenheit,

fifteen minutes, and at 500? Fahrenheit, eight minutes. In any event, products having unusual tensile strength, and high water-resistent properties are produced.

We claim as our invention. I 1. A process for the purpose described consisting Y in flberizing raw wood to produce a fiber too long and too coarse for the coarsest gradeof paper,

making an emulsion of a raw drying oil and water,

by using oilain quantity equal to about ten per cent of" the weight of the finished product,

and water in an amount substantially equal to the weight of the oil, adding a wax to the oilin proportion of about one to four per cent or the dry weight of the finished product and before emulsitying, adding to the water a quantity of soda ash within-the rangeof one to two per cent of the weight of the oil, adding the sodaashwater to the oil to complete the emulsion,. adding the emulsion to the pulp, precipitating the emulsion, forming a porous sheet, dryingthe sheet to remove about ninety-flve per cent of the water, and then simultaneously applying heat and pressure 'to the sheet, with-the pressure within the range of from three hundred to six hundred poundsper square inch, and the temperature within the range of from three hundred toflve hundred degrees Fahrenheit, and operating from fifteen to forty-minutes.

2. A process for the purpose described consisting in flberlzing raw wood to produceianber toolong and too coarse for the coarsest grade of paper,-

making anemulsion of a drying oil and water.

using oil in quantity equal'tojabout ten per cent of the dry weight of thefinifshed' product, and an amount of water substantially equal to the weightof the oil, adding a waxto the oil in proportion of one to four per cent of the dry weight of the finished product and before emulsifying, adding to the water a' quantityof soda ash within the range of one to two per cent of the weight of the oil, "adding the soda-ash water to the oil slowly while rapidly agitating, adding the emulsion to the pulp, adding alum,forming a poroussheet,

drying the sheet to remove about ninety-flye per cent of water, and simultaneously applying heat and pressure to-the sheet with the pressure {with-- in the range of from three hundred to six-hundred;

pounds per square inch, and with thetehrpera ture within the range of from three hundred to I ,iive hundred degrees Fahrenheit. andoperating from fifteen to forty minutes.

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