US2225100A - Manufacture of sheets or boards containing mineral wool - Google Patents

Description

UNITED STATES PATENT OFFICE MANUFACTURE OF SHEETS OR BOARDS CONTAINING MINERAL WOOL Albert L. Ciapp, Danvers, Mass.

No Drawing. Application May 9, 1938, Serial No. 206,840

10 Claims.

In my application Serial No. 185,784, filed January 19, 1938, of sheets or boards c more especially long I have disclosed the manufacture ontaining mineral wool and -fibered mineral wool by a process which involves treating or soaking a mass of aggregated mineral or rock wool fibers, as it is available on the market, substantially uniformly with a slimy material and then manipulating the slime-treated or soaked mass in the presence of water, as in a mixing or beater engine, to liberate substantially completely the fibers of the mass and thereby to sion of the substantially completely bers.

preserve largely or produce an aqueous suspenliberated fi- The mixing or beater action is controlled to practically completely the original length of the mineral wool fibers in the course of theirliberation and suspension in water so that the resulting suspension mineral wool fibers, ranging contains the from a fraction of an inchto several inches, constituting the starting mass of aggregated or tangled mineral wool fibers. 'Once the aqueous mineral wool fiber suspension is produced,

and other purposes, p

cible binders, such as dispersions of bitume mixed therewith. In

mentioned application,

,it is possible to spread it for instance, to use it plaster for insulating articularly when water-missodium silicate, aqueous n, resins, or the like, are adaccordance with the aforethe aqueous mineral wool fiber suspension is produced in a relatively large amount of water, for yield a suspension of instance, sufilcient water to about 3% to 4% fiber content, and, alter further appropriate dilution with water, is formed into making machine.

a shgt or board on a paper- ,1 As described in that application, it is frequently desirable to produce an aqueous suspension of mineral wool fibers blended with cellulose fiber and/or asbestos or the like, in which case, the

slime-treated mineral wool fiber mass is added with proper manipulation to an already-prepared aqueous charge or. the cellulose fiber and/or to an already-prepared aqueous suspension of the asbestos fiber, as in a beater engine. The resulting aqueous suspension of mineral wool fiber blended with more asbestos fiber is then designed for various or less cellulose and/or formed into sheets or boards purposes, for instance, for

use as thermo-lnsulating'material in buildings,

refrigerators, and other structures. finished sheets are to when the be used as wallboard or the like, they may contain a substantial proportion of both cellulose an d asbestos fiber as well as.

mineral wool fiber. However, should the quality of substantial fireproofriess be desired in the finished sheets or boards, they may contain little, if any, cellulose fiber and be composed essentially of the mineral wool fiber or a blend of such fiber 5 and asbestos fiber. In some instances, the finished sheets or boards may be impregnated with sizes or binders of various kinds, which, as disclosed in the aforementioned application, may be incorporated into the aqueous fiber suspension from which the sheets or boards are formed and/or be infused into the already-fabricated sheets or boards.

I have now ,found that when a slimy watersoluble soap solution is used for the purpocse of treating or soaking the mass of aggregated mineral wool fibers preparatory to the manipulation of the slime-treated mass in water for the purpose of liberating the individual fibers of which the mass is composed, it is distinctly advantageous that the water in which such manipulation occurs contain a chemical reactive with the Water-soluble soap to form a water-insoluble soap gel or slime, for such latter gel or slime is even far more effective than a water-soluble soap slime in promoting the desired loosening and segregation or liberation of the individual fiber units from the mass and thereby yielding the desired aqueous fiber suspension whose fibers are of a length approximating those in the original mass 0 and which is practically devoid of clumps or tangled fibers. It will thus be seen that a slimy water-soluble soap solution is initially used so as to realize the desired penetration and soaking of the mass of aggregated fibers, as this ensures substantially uniform access of the slime to substantially all of the fiber surfaces. Once the fibers in the mass have been substantially uniformly enveloped or protected by the water-soluble soap, slime and the mass is to be manipulated in water, it is desirable that the slime resist dispersion or difi'usion from the fiber surfaces into the aqueous phase until fiber-liberation has been largely substantially completed; and this is accomplished pursuant to the present invention by converting the water-soluble soap slime on the fiber surfaces to a water-insoluble soap slimethrouglr the action of suitable chemicals present in thewater, namely, chemicals which furnish the positive radical of a water-insoluble soap, for instance, 0 chemicals of the nature of alkaline earth metal oxide or hydroxide, metal salts, etc. Lime, magnesium oxide or basic carbonate, or equivalent alkaline earth metal compounds are generally preferable by virtue Ofthe fact that they render al- .mass, but it is preferable that kaline the aqueous medium in which the slimetreated fiber mass is being manipulated. An alkaline medium evidently functions to preserve the strength of the mineral wool fibers as they are being liberated from the mass and hence minimizes cutting or fracture of the fibers, whereas salts, especially of an acidic nature, such as alum, although useful for the purposes hereof, appear to weaken or tender the fibers as they are being liberated and hence to make more difficult the desired preservation of the fibers at substantially their original length.

While not limited thereto, the prese t invention will now be described in terms of he manufacture of wallboard or insulating board containing asbestos and cellulose fiber. Any suitable cellulose fiber, such as groundwood pulp, and suitable asbestos fiber, preferably short-fibered asbestos, may be added to a beater engine in proportion to yield a finished sheet whose fibrous content will consist of, say, about 25% of asbestos, about 25% of groundwood pulp, and about 50% of the mineral wool fiber. The groundwood pulp not only reduces the cost of the sheet but serves, on account of its short fiber length, to improve its texture or formation. The short-fibered asbestos, which is also inexpensive, not only improves sheet formation but assists to some extent in liberating or individualizing the mineral wool fibers of the slime-treated mineral wool fiber mass subsequently added to the beater engine. The asbestos also enhances the freeness of the stock even though it wets up and absorbs water readily. The groundwood pulp and asbestos are mixed in ample water in the beater engine until a substantially uniform aqueous fiber suspension is realized, whereupon about 5% of lime, calculated on all the fibrous components of the finished sheet or board (including the weight of the mineral wool fiber component subsequently added) is admixed with the aqueous suspension of blended asbestos and groundwood pulp.

The mineral wool fiber mass to be added to the fiber suspension in the beater engine is prepared or conditioned for such addition by undergoing a substantially uniform wetting or soaking treatment with an aqueous solution of water-soluble soap in slimy, preferably heated, condition. Specifically, a mass of the aggregated mineral wool fibers consisting of fibers ranging from a fraction of an inch to several inches may be thoroughly soaked with excessive heated soap solution, such as a 3% to 5% solution of sodium stearate or other fatty acid soap. The soap solution may be produced by dissolving the soap in hot water, whereupon, while the soap solution is still hot or warm, the mass of mineral wool may be submersed in an excess of the solution so as to ensure uniform wetting of substantially all the fiber surfaces with the solution. The desired results are had when about 200 parts of the mineral wool fiber mass are plunged into about 1,000 parts of a hot soap solution of about 3% to 5% strength. Excess soap solution may be drained and, if desired, gently squeezed from the upwards of about 150% tion upon being added of its weight of soap soluto the beater engine. Upon being added to the beater engine, which contains, for example, a lime water suspension of the asbestos and groundwood pulp, the soapsolution-soaked mass of mineral wool fibers is subjected to manipulation and, in being manipulated, the lime water quickly diffuses to the soapy slime enveloping the fibers and reacts the mass contain therewith to form a water-insoluble soap slime, namely, a, calcium soap slime. The calcium soap slime resists, on account of its water-insolubility, displacement or dispersion from the mineral W001 fiber surfaces. Accordingly, such slime tends to remain present on the 'fiber surfaces during the manipulation of the aggregated mineral wool fiber mass until the fibers, as a result of the continued manipulation of the mass, have been substantially completely liberated or individualized in the aqueous medium and commingled with the asbestos and groundwood pulp fibers. In other words, the calcium soap slime evidently affords the desired lubricating action on the fibers and is not materially diluted or dispersed in the beater water until the fibers of the mass have substantially completely parted from one another and the originally aggregated fibers of the mass have been resolved into individualized or disaggregated fibers and have been substantially uniformly dispersed along with the asbestos and groundwood pulp fibers in the aqueous medium. The substantially complete liberation and dispersion of th mineral wool fibers in the aqueous medium requires only a comparatively short period of time, for instance, about 5 to 15 minutes or so, the particular time depending, of course, on the particular mixing or beater engine and the amount of stock charged thereinto. It might be noted that the mixing or beater engine used for the purposes hereof need not be of that type ordinarily used for papermaking, that is, the type comprising a beater roll equipped with sharp blades or knives arranged in fiber-cutting or beating relationship to a bed-plate. On the contrary, the mixing or beater engine used for the purposes hereof may comprise as its mixing or beating instrumentality nothing more than a paddle wheel, under whose action the desired or manipulate the mineral wool fiber mass in the beater water. The same sort of manipulation, agitation, or mixing action is also all that is usually necessary for slushing the asbestos and groundwood pulp to form a smooth fiber suspension. The finished aqueous fiber suspension consisting of a blend of mineral wool fiber of substantially original fiber length, asbestos, and groundwood pulp, may be of about 3% stock or fiber content.

Once the mixed substantially completely individualized fiber suspension has been produced in the mixing or beater engine, various sizing agents, fillers, pigments, etc. may be added thereto. For instance, about 5% to 8% cooked or raw starch, based on the dry weight of all the fibrous components, may be added to the fiber suspension so as to enable the realization of a finished sheet or board of marked stiffness by reason of its starch content. Again, alum in the amount of, say, about 2% to 3%, based on the weight of the fibrous components, may be added to the mixed fiber suspension so as to precipitate or fix on the fibers such residual lime and/or water-solublesoap as may have escaped interaction. It is generally preferable, however, to add alum in amount short of imparting an acid condition to the fiber suspension, that is, in amount to leave the suspension at a pI-lf value of, say, 7.5 to 8.5,

for delivery to the papermaking machine. On its; way to the papermaking, or -board-forming. ma-

chine, the fiber suspension maybe diluted with further water to appropriate sheet-forming, or board-forming consistency; and, should there be excessive foaming tendency in the suspension on account of its content of calcium fatty-acid soap, suitable anti-foaming agents, such as kerosene and/or paraflin wax emulsion may be added thereto. The sheets and/or boards may be formed on the papermaking machine in much the sameway and for much the same purposes asdisclosed in my application Serial No. 185,784; and the resulting sheets or boards may, if desired, undergosuch after-treatment or after-impregnation with suitable binder, waterproofing material, or the like, as disclosed in that application.

It is to be understood that the process hereof l is subject to variation, so far as concerns, for example, such features as the particular watersoluble soap slime used for soaking the mass of mineral wool fiber, the strength of the-aqueous water-soluble soap slime, the. particular fibrous composition orvfurnish'. for .the finished sheetl or 1* board, and the particular kind of chemical used 1 to convertthezwater-soluble soap slimezin-qthe' mineral'woot fiber mass to'a'watereinsoluble soap slime, as it is being manipulated in waternGen ei'al lyspeakingxit is preferable-.to' -u'se fatty-acid soap *slim'e's of the natureof sodium 'stearate and/or sodium palr'nitate' and/or sodium .1 oleate or the like, but it is possible, ofacourse, to use the potassium soap of the fatty acids or 'other"water-" J soluble "alkali-metal soap solution for initiallysoaking the mineral wool fiber mass; Although rosin soap slime is not so effective as-fatty acid soap slime, yet it' may'be used in some instances, especially in admixture with fatty acid'soap slime; Again, the soap of the substance known commercially as tallol, which is a by-product of kra'ft pulp manufacture, may be used. Tallol soap, which may be prepared by sapo'nifying the tallol wlthalkali-metal hydroxide, such as sodium or potassium hydroxide, is a complex material containing fatty acid soap as well as rosin soap; and it may be used as a slimy aqueous solution of suitable strength for soaking the mass of mineral wool fibers. In lieu of forming the sheets or boards hereof from the particular mixed fiber suspension hereinbefore described, that is, a fiber mixture containing about 50% of the mineral wool fibers and about 25% each of asbestos and groundwood pulp, it is possible to'form such sheets or boards from an aqueous fiber suspension consisting essentially only of the mineral wool fiber or consisting of a mixture of the mineral wool fiber with, say, about an equal amount of asbestos. Again, it is possible to form the sheets or boards hereof from an aqueous suspension of mixed fibers containing, besides the mineral wool fiber, various proportions of asbestos and cellulose fiber, for instance, chemical wood pulps, such as kraft and/or sulphite pulp, waste papers, rag pulp, etc.; and, if desired, the mixed fiber suspension may contain animal fiber, such as cattle hair, wool, or the like.

It is to be understood that the process hereof constitutes essentially an improvement of the process outlined in my application Serial No. 185,784, more especially in those instances when a water-soluble soap slime is used in initially treating or soaking the mass of mineral wool fiber, and that such improvement consists essentially in converting the water-soluble soap slime into a water-insoluble soap slime by the addition to the erated' fibers. 1

water in which the soaked fiber mass ismjanipu lated of a chemical furnishing the ion (i. e,, .positive alkaline earthmetal or'metal ion) combinable with fatty acid to yield water-insoluble fatty acid soap; It is, as already indicated, preferable to 5 disseminate such chemical,.e; .g., lime, through-, out the water in the mixing or beating engine, before the addition and manipulation of the s'oapsolution-soaked mass of mineral wool'fiber in the water, but such chemical; may be added to the '10, water simultaneously with the addition of such mass or during the veryearly stages of manipulating such mass in the water. ,Other than the particular improvement herein indicated, the process hereof is akin to the process of theaforementioned application andmay involve the various features indicated in that application Iclaim: r u

1. A process which comprises treating almass ous slimeof water-soluble so'apgof at least about- 3%.soa'p content so-as toenvelop;the'fibersgsubj w v 1 stantial-ly 'uniforrnlyw ith, the slimegandagit stantiall-y completely-liner suspension die the subs ntiall of at least a ut 3% soap,;co'ritent streamin ,such slime-treatedmass of. aggregated fibers in I water containing a chemical that reacts with'sai d soap and forms a' water-insolublesoap slime until the fibers of said mass have been substantially completely liberatedto yield an aqueous suspension of the substantially completely liberated 40 3. A process which comprises treatinga mass of aggregated mineralwool fibers with aqueousslirne of water-soluble soap in amount infexcess of that'- necessary to envelop the fibers substantially unifo'rmly with the slime; removing excess slime from said mass; and agitating said slimetreated mass in lime water, thereby converting said slime into calcium soap slime, until the fibers of said mass have been substantially completely liberated to 5 yield an aqueous suspension of the substantially completely liberated fibers.

4. A process which comprises thoroughly soaking a mass of aggregated mineral wool fiber with aqueous slime of water-soluble soap in amount 5 in excess of that necessary to envelop the fiber substantially uniformly; removing excess. slime from said mass; and agitating said slime-soaked mass in lime water, thereby converting said slime into calcium soap slime, until the fibers-of said 60 mass have been substantially completely liberated to yield an aqueous suspension of the substantially completely liberated fibers, said agitation being controlled to preserve largely the original fiber length of said fibers.

5. A process which comprises treating a mass 'of aggregated mineral wool fibers with aqueous slime of water-soluble soap of at least about 3% soap content in amount in excess of that necessary to envelop the fiberssubstanti ally uniformly with the slime; removing excess slime from said mass; adding the slime-treated mass to an already-prepared suspension of asbestos and cellulose fiber in water containing a chemical that reacts with said soap and forms a water-insolan aqueous slime of'water'esolub fatty-acid 15 4 uble soap slime; agitating said mass in said water to liberate substantially completely the fibers of said mass and thereby to produce an aqueous slime of water-soluble soap in'amount in excess' of that necessary to envelop the fibers substantially uniformly with the slime; removing excess slime from said mass; adding the slime-treated mass to an'already-prepared suspension of asbestos fiber in water containing a chemical that reacts with said soap and forms a water-insoluble soap slime; agitating said mass in said water to liberate substantially completely the fibers of said mass and thereby to produce an aqueous suspension of thesubstantially completely liberated fibers, said agitation being controlled to preserve largely the original fiber length of said mineral wool fibers; and sheeting the mixed fibers from the resulting aqueous suspension.

7. A process which comprises treating a mass of aggregated mineral wool fibers with aqueous slime of water-soluble soap in amount in excess of that necessary to envelop the fibers substantially uniformly with the slime; removing excess slime from said mass; adding the slime-treated mass to an already-prepared suspension of cellulose fiber in water containing a chemical that reacts with said soap and forms a water-insoluble soap slime; agitating said mass in said water to liberate substantially completely the fibers of said mass and thereby to produce an aqueous suspension of the substantially completely liberated fibers, said agitation being controlled to preserve largely the original fiber length of said mineral wool fibers; and sheeting the mixed fibers from the resulting aqueous suspension.

8. A process which comprises thoroughly soaking a mass of aggregated mineral wool fiber with aqueous slime of at least about 3% concentration of water-soluble fatty acid soap in amount in excess of that necessary to envelop the fiber substantially uniformly; removing excess slime from ing a mass of aggregated mineral wool fiber with aqueous slime of water-soluble fatty acid soap in amount in excess of that necessary to envelop the fiber substantially uniformly; removing excess slime from said mass; adding the slimesoaked mass to an already-prepared suspension of asbestos in lime water, thereby converting said slime into calcium fatty acid soap slime; agitating said mass in said water to liberate substantially completely the fibers of said mass and thereby to produce an aqueous suspension of the substantially completely liberated fibers, said agitation being controlled to preserve largely the original fiber length of said mineral wool fibers; and sheeting the mixed fibers from the resulting aqueous suspension.

10. A process which comprises thoroughly soaking a mass of aggregated mineral wool fiber with aqueousslime of water-soluble fatty acid soap in amount in excess of that necessary to envelop the fiber substantially uniformly; removing excess slime from said mass; adding the slime-soaked mass to an already-prepared sus-' pension of cellulose fiber in water containing lime, thereby converting said slime into calcium fatty acid soap slime; agitating said mass in said water to liberate substantially completely the fibers of said mass and thereby to produce an aqueous suspension of the substantially completely liberated fibers, said agitation being controlled to preserve largely the original fiber length of said mineral wool fibers; and sheeting the mixed fibers from the resulting aqueous suspension.

' ALBERT L. CLAPP.

as I