Document nmRvxMe3LOOaZjpNb5R1rOB4X

FILE NAME Keene KNE DATE 1956 Jan 24 DOC KNE003 DOCUMENT DESCRIPTION US Patent - Method of Making Mineral Wool Insulation Office TR United States Patent OfficeOffice Office Office 2,732,295 Patented Jan. 24 1956 2 . eg, infusible Wem MIN OF ME AKIR NG MA INEL RAL INSULATION corporated Frederick H. Hollenberg Jr. Maple Heights Ohio as in the interfelted web is converted by heat to in insoluble stage Since the bentonite is in in the inorganic fibrous pres in e the n prec sene ce aqueous medium the water will swell the bentonite the final product will contain bentonite in its swollen signor to Baldwin Company Trenton N. I. a cor- In the preferred embodiment of the invention the sheet poration of New Jersey of insulating material which is subjected to heat to convert No Drawing Original application May 2 1946 Sertal No. 666,807 Divided and this application September 22 1952 Sexial No. 310,920 the resin is formed from an aqueous suspension of the fibrous material by the use of a screen to remove water therefrom Preferably the thermosetting resin and C"hafins CL 92 21 The present invention relates to at inorganic fibre insulating material of unusual and improved properties and to a wet process of producing the same and more particularly it relates to an insulating shee material which is characterized by its resistance In addition the invention relates to an aqueous resinous composition which is available for use in the production of inorganic fibrous insulating material possessing water- and fire sistant properties The present application is a division of application Serial Number 565,807 filed May 2 1946 Dow Patent Number 2,633,433 One object of this invention is to provide an inorganic fibre insulating material which while relatively light possesses high fiexural strength is waterproof fireproof and has high electrical and thermal insulating values Another object is to furnish an insulating material which possesses in addition to other desirable properties fire- resistance and which if raised at one portion to the com- bustion temperature of the resin will provide a barrier preventing propagation of thermal decomposition in ad- jacent portions of the product . A further object is to provide an economic and com- mercially practical method of producing an insulating material comprising inorganic fibrous material a syo- thetic resin binder and bentonite the lafter ingredient not only imparting resistance and other desirable properties to the product but also facilitating the practice of the process Still another object of the invention is to provide method of producing an insulating material by which various types of thermosetting resins including a soluble resin even in a very dilute solution may be used and in which the white water may be utilized to make up new stock solutions Still another object is to provide a resinous composition comprising a soluble thermosetting resin in solution in an aqueous medium and a retardant in suspension therein which composition is availat e for use in the production of insulating material of improved improved properties Other objects will be apparent from a consideration of this specification and the claims The insulating material of the present invention comprises an interfelted web of inorganic fibrous material and a synthetic resin in its insoluble infusible stage and bentonite incorporated in suid interfelted web the resin and bentonite providing resistance and resizt- ance respectively to the product as will hereinafter be dis- cussed In one preferred embodiment the resin and bentonite are distributed throughout the interfeited web substantially uniformly but if desired the product may have more resin in the outer sections than in the center section and the resin may even be substanticoanflilneyd . to the outer sections . The product may be preparebdy any procinews his ch a thermosetting resin and bentonite in the presence of an aqueous medium is incorporated in inorganic fibrous material the fibres of which are interfelted in an aqueous suspension thereof and in which the ersin after its associ- frited web for example to the wet fibre on the sheetproducing areen or subsequently If desired instead of forming the interfelted web from an aqueous suspension by the use of a screen a smaller amount of water may be empl ando theyree sultd ing suspension may thbe e dn eposited sither continuously on & conveying system or for intm e fos rms As will hereinafter appear other suppsl ucheasmaesun pplt emeantl al reurdaaden foat m- ing agent a bentonite reducing agent or both may advan be t adda ed ag t ae suio tablu e ps ointl in y the process By inorganic fibres is meant what is generally knoiw n tn he industry as glass wool mineral rock or slag wool and asbestos fibres and all these will be refered to generally herein as fibres Any one of these fibrous materials may be used advantageously in the process the use of mineral wool being generally preferred and mixtures of any two or all of them in varying pro- partions may be milized For example portions of long fibre asbse uchsastamo oss ^>temay be advantageously mixed with glats wool or rock wool or both to provide additional strength to the finished board In the case of the use of the glass or rock wool either fibre or loose wool or what is known in the trade as granulated or nodu wool l mi ayz beeusd ed The granuiased or nodulized wool is prepared by nodulizing the wool on a rotary screen which aiso removes the major portion of the shot that is the glass granules of nonfiberized material When fibre wool is lara g lare ge of the shot is advantageously removeidn the process for example by a riffle box The remov ofatl he major portion of the shot is important since obviously substantial quantities of it will seriously alter the weight of the finished board without changing the volume appreIn the preferred embodiment of the invention grann- lated or nodulized wool is employed since the finished product will have lower thermal conductivity lower density greater strength and better handling properties as compared to a product made from fibered wool , Mixtures of nodul ani d nz odue lizded wo mayo be ul sed if desired By therrm esio n iss mee ant t anyt syni thetn ic rg esin in an initial stagoef polymerization which is convertible by heat to the insoluble infusible state Such resins may be used in any one of the three following forms I as an aqueous solution of a soluble liquid thermosetting resin 2 as an aqueous emulsion of a therthm ermoo settis ng re esint in t liquii d fon rm g and 3 as an aqueous dispersion of a insolubl thee r- mosetting resin in a dry powdered finely divided form Mixtures thereof may also be used if desired The first two forms contain liquid resins as distinguished from the powdered resin of the third form . While any of the thermoressienstortuirnegs TO thereof may be employed for example formal- dehyde formaldehyde formaldehydaned wor SEES 1,788,295 ..: ee? \ 746d^ced by leatting pheodi with formaldehyde use of a formaldehyde for zinc furfural formaldehyde a may be used with a powdered resin but not with the a formaldehyde substance is preferred Exam- liquid resin due to its reactivity with the latter The proportions of inorganic fibre resin and bentonite ples of the phenols are phenolyielding cresol and xylenot and examples formaldehyde substaarne cfoerms- 5 in the finished product may vary widely but since these paraformaldehyde aldehyde and bexamethylenetetra- bexamethylenetetra- mine The amal extenders of modifiers such as Vinsol resin which is a thermoplastic insoluble hyde and ether groups Dresinate which is a sodium or 10 potassium soup of rosin and Le like may be included the resinous composi 15 for instance from 85 to 90 fibre % to % resin and % to % bentonite In typical example the in- sulating material contains 87 rock wool fibre % of formaldehyde resin converted to its infusible in- soluble state and % of bentonite in another example contained the finished product 92 of rock wool fibre % of a converted formaldehyde resin and serves to render the product resistant of % bentonite When a supplemental retardant thereof The resins used in this procem being of a combustible is included in the product the amount may vary from a very small amount for example a few tenths of nature will undergo thermal decompositiez decompositiez when subjected to high temperatures even when the resin is in- a percenutp to % of even more based on the weight | of the resin and the amount employed in any particular corporated with the inorganic fibrous materiailn the case will be determined by the degree of supplemental etBose The inorganic fibres in the finished particles finished product form an insolating blanket over the resin retarding action desired EG product dissipated The insulating material of the present invention is EES: and proof- preventing the heat of combustion from being characterized not only by resistance WIT E S and due to the presence of the fibres air can breathe ness but also by high electrical and thermal insulation stehernoutghhertehfeorc e to hatm ? tb aonysr uppope rotritot ncooi mfbtro heetin boinnderItiscraaisn beed 35 vsatrleunegsth Istouinsd faubrstohrerbincghaprraocpteerritzieeds banyd hriegshistfalnecxeuratlo eIptegest to the combustion temperature of the resin mermal de- vibration Referring to resistance a sample of the insulating material of the invention was found to have absorbed less than % water in an atmosphere of 95 of serves as the means for preventing the propagation 40 thermal decomposition through the product Bentonite acts as an excellent retardanfotr all the various types that may of thermosetting resins be used in the production of the insulating material since the bentonite provides a mechanical barrier between the portion of the product which has been raised to the combustica point of the resin and the adjacent portions In the event the product is subjected to a temperature sufficiently high to cause used in The product tres fusion of the bentonite the fused bentonite then serves relative humidity at a temperature of 120 F. Even when the material was submerged in cold hot or boil- ing water it did not deterio~ ate and after the wet in- stil^tingmaterial was dried the original strength was re- tained Tests of the product by the Columbin time- temperature method showed no evidence of burning Furthermore the product is characterized by its ease of handling and may be utilized with a minimum of dusting and breakage and therefore with practically no indus trial health hazard way therefore be any application where such properties are de tirable The weight per cubic foot of the product may vary over a wide range depending upon the process steps em- ployed in its pro~ ucti^^n swill hereinafter be described prmaqewct and usually the weight per cubic foot will be between 55 about 6 and 25 pounds When the product is to be used ^^ninsulating material fot thips or in other applica tions where a light weight product is desired the weight per cubic foot is advantageously between about 6 and : coewas 10 pounds various As previously stated various processes may be used exceed the resin content for example with a product containing % train about % bentonite may be present in the preparation of the product and the particular pr^cest depends on whether in equ^ouss^lutionan emulsion be a dispersion is initially employed Furthermore when whereas with a resin content of % the bentonite content an aqueasolution is employed the process depends may only be about % on whether the resin will remain in solution when the As previously stated if desired the retardant cha scteristics of the bentonite may be supplementebyd the presence in the product of another retardant While solution is brought into contact with the water employed in the pro~ essor wheth^rthe resin will precipitate under ruth conditions These two types of initial aqueous solutions are termed precipitatable and has precipitatable respectively When bentonite included in the aqueous solution of the resin the en the d^'pendup^n^filsability to be used in the process without difutability of the solution without precipitation of the is e undesirable reaction with the resin and to be retained fesinis fesinis markedly intensed so that a solution which in- in the Anished material Certain substha^/nvicngefirse- hormally pr^'cipitatablemay become upon the retardant properties are trailable for is due to 75 ion of bentotile the precipitatable type 2,782,295 pe S . In typical case where it is desired to employ a non- precipitatable solution and to provide a solution after dilution with the water employed in the process of 6 interfelted web after its formation for instance on the ea forming screen or after removal therefrom either e , % by weight of resin solids an initial solution con- raedium containing the resin and bentonite Since the taining 70 resin solids und having a dilutability of at web is formed from a suspension of the inorganic least 14 water to 1 solution by weight is employed fibrous material it is a water web and as is usual a In a typical case where it is desired to employ a resin- in water web the major portion of the fibres there- precipitatable solution and to provide a suspension con- in are oriented in a plane substantially parallel to the taining % by weight of precipitated resin solids after plane of the web or sheet If the dried treisattree atd ed dilution with the water employed in the process an 10 it may or may not be wet prior to the application of Ne initial solution containing 70 resin solids and having the carrying medium but of course if a precipi- at a dilutability of less than 14 water to 1 ztion by tated resin is desired the product must contain sufficient weight is used Illustrative of the effect of bentonite if water to cause a precipitation of the resin when a resin- a solution containing % to 10 by weight of bentonite precipitatable solution is employed Furthermore if s in u solsutp iionnesaun fstpes ernsdi iiolno utain onnd w% ithbtyhewwae teri ofemrg epslionh yseodlt iidns 15 desired instead of treating the interfelted web with an the process if desired it is not necessary to use an Initial resin solution having a dilutability of at least 14 1 but a solution of a dilutability ratio of less than to 1 may be employed provided the dilutability ratio greater than about 4 to 1. Thus the bentonite will serve to convert a precipitatable solution into a bentonite the bentonite may be incorporated with the fibres prior to the interfeiting step or subsequently thereto and after drying the product may be treated with an aqueous solution or emulsion for example by spraying pdroductipping or passing the solution or emulsion through the precipitatable solution When a precipitatable solution is applied to the It is to be understood that the resin content of the intertelted web whether it be on the forming device or solution or suspension after the dilution by the water in subsequently the water associated with the web and the the process may vary widely for example from about displaced water is drawn through the web as filtrate 14 to about 20 by weight of resin sclids and that Since the presence of the water in the web raises the an initial resin solution to provide such resin content will amount of water in the resin solution above the critical be employed This is also the case when a resin emul- dilution ratio the resin is precipitated from the solu- sion or dispersion is used of tion and is dispersed throughout the wet web Likewise the bentonite content of the water medi- The interfelted web of inorganic fibrous material um after the dilution by the water in the process may whether the resin be associated with the fibres prior to vary widely for example from about % to 18 by the formation of the web or advantisaagdveanotaugesoulslyy weight of bentonite and an initial amount of bentonite formed on the screen of an Oliver filter or other type to provide such quantity will be employed The bentonite is preferably moistened with sufficient water to swell it of revolving screen equipped with vacuum compartments before it is incorporated with the water medium but if desired the web may be farmed on the usual cylinder type of paper machine or on the screen of a Four- When bentonite is employed in the upper portion of the drinier machine Thereafter the web is subjected to range for example about % and above the viscosity the action of a pressure roll or rolls in order to compact of the medium is high and with relatively thick prod it to some extent and to smooth the surface and after ucts difficulty may be encountered in removing excess the treatment with the beatocite and resin as described liquid from the interfelted web when a screen is used the interfelted web is dried and heated to convert the resin in the formation thereof In order to decrease the to the insoluble infusible state In the preferred em- viscosity of the medium particularly when more than bodiment of the invention the interfelted web is formed about % bentonite is present it has been found that by the process described in Patent No. 1,865,049 except this may be accomplished by the inclusion in the resin- when granulated or nodulized wool is employed the riffle water medium of a small amount of a soluble polyphos- box may be omitted As stated the use of pressure rolls phate for example sodium er potassium hexameta- is recommended since they serve to etablish etablish the thick- phosphate tetraphosphate or pyrophosphate sodium ness of the product at a predetermined point For ex- tetraphosphate being preferabl employed When a 50 ample in the preparation of a one inch board the suc- soluble polyphosphate is employed some of it at least will tion may be applied so that the stock will build up an be present in the finished converted product The interfelted web of approximately one and eighth amount employed may vary om a few truths of a per inches and by passing under the pressure rolls the thick- ce upn tot % or more based on the weight of the ness may be reduced to one inch , bentonite The preferred range is from about 0.5 to 65 When the stock solution delivered to the screen con- about 1.5 Thus in a typical case where an % sus- tains the resin and bentonite as well as the inorganic pension of bentonite after dilution by the water in the fibrous material the solution may foam and if this con- process was used and % of sodium tetraphosphate dition is encountered a suitable reducing agent was present the viscosity was reduced approximately to adbd e ae ddd ed . that of a % bentonite concentration concentration In the case where the suspension of fibre bentonite bentonite and resin is sufficiently The subseweqb u is e subnset quelnty ly heatotdre y td he concentrated so that it is not to web and convthe e r rest in to the infusible insoluble state necessary remove ex- cess water by a screen the use of a polyphosphate is and the product may be cut to the desired size for ex- usually not required since a high high viscosity is an advantage ample by means of circular discs revolvingat revolvingat high speed - The process is preferably arried out by mixing the either before or after the drying and heat treatment The resin and the bentonite with he inorganic fibrous ma- 65 interfelted material may be heated by any suitable means terial before the interfelted w.b is formed and in this and the temperature of the treatment will depend type of process the recipitating solution the upon the particular resin present in the interfelted struc- resin emmision or resin dispersion may be added to the ture Advantt he wa et g intee rfelo ted u webs is l play ced beater mixing or agitating tank or head or delivery upon pallets which support it in a flat form and are de- ee bsotxeadtoofthuesisncgreaenscruesened ttoo f foro mtthr hee wwm eebb a Ifcdoensvieryeodr ionr- 70 spialglneetds taoreimpplaarctedtoonthcaersweabndathsemocoatrhs filnattusrunrafraecpelaTcheed e stationary form may employed In this case the use in a drying tunnel The drying tunnel is usually kept ee of granulated mineral wool is advantageous ll * at a temperature of between 250 F. and pre a p- re- In the case a precipitating solution ^ resin- ferred range being between 300 F. to 350 F. At this precipitating solution or a resa emulsion is used the 76 temperature the water is evaporated and the resin is we ~e e 1,462,995 ae yy .. converted to the infuable insole . The Schijith B each other are associated are felted into a thick sh et of live of techp is a e funcr tionaof t the i techv perae tive employed and usually requires that hoon or inore drying and beating said sheet to convert the condensation product therein into the insoluble infusible state When the interfelted web contain a resis which & 2. The process of claim 1 wherein a soluble alkali tk^/l solable in the resident wat~ sdrying for sai web, th^re a tendenc^"during th^drying cycle for sai resin to migrate to the outer surface This migration resaits polyphosphate is present in thesuspension . . 3. The process of claim 1 wherein said condensation 4 e product comprises a formaldehyde condensation in a product that has a strong ^ftercrust bez a desirable umber core While such a product ^fin at times desirable product 4. The process for producing mineral wool insulation i in board form possessing a low density of between about 6 and 25 pou per n cubid c fs oot high strenfigretrhe- sistance and waterproofness which comprises mixing with a practical standpoint very little occurs although there usually is a slight me,, eas^efinresin concentraotnitohne 15 outer surface This sight increase is beneficial provides & a l^finished product which is treat to hinde ^finfact before in cases where the product has been eit migration conversi^nof the resin then the slight migratipor^nvidea productin which the incl theu rmad l ii ncln udig ng the edges and ends are neatly sealed aqucos water nodulized mineral wool asbestos fibres bentonite and a synthetic thermosetting condensation product selected from the group consisting of formaldehyde re- formaldehyde formaldehyde and furfuralformaldehyde condensation products to provide a suspension in which the concentration of bentonite is between about % and about % by weight and of condens~ tion product between 1 and about 20 by weight continuously feeding said suspension to a continuously moving screen drawing water from said suspension Regardless of the particular form of aqucos resin medi^"memployed it will be desirablteo recirculatthee water removed through the screen This is particularly important when a precipitating solution is zin- of the ployed since the resin and bentonite contum white water remains substantially constant Such a spintion is normally relatively unstable and there is a tendency for the resin upon standing to separate from the solution 30 The use of bentonite in such a solution however makes it possible to obtain resin solstu ablt e ovi er ao pern iods of months and in fact the stability of sich a solutioinncreases upon aging The stability imparted to such a solution by the bentonite therefore makes it ponible to recover and use the white water As stated previously one invoef tnhetinivenotinon is provide a resinous coraposition comprising a soluble thermosetting resin in solution in an aqueous mediuma and betonite suspended therein which composition In useable in the production of insulating material In making such a compitowils l beidest irai ble o to fn irst suspend the bentonite in water to swell it and then to incorporate it with the resin solution The concents tions of bentonite and resin in the solution may corre be in the spond to those of the solution to used pr^duc- tion of the insul~ ting material such for example as con- those giver above but it is advantageons to make inore concentrated solution for example a solution the taising from 20 to 50 of resin and from % 40 of bentonite and then to dilme this solution at tim~ ^fits use The presence of the bentonite stabilizes the te inas here^fl^"b^'doers~cribed proportions proportions Considerable modification is possible in the proportions of the Constituents of the insulating material of the in- the vention as well as in the steps of producing same without departing from the essential feames of the the wool fibres and through said screen wheremib nery al asbestos fibres with which bentonite and condensation ciated in intimate mixture with each other are asso- ciated are felted into a thick sheet drying and heating mid sheet to convert the condensation product therein into the insoluble infusible state 5. The process of claim 4 wherein a soluble ^/lk^/~i metal polyphosphate is present in the suspension 6. The process of claim 4 wherein said condensation product comprises a phenol formaldehyde condensation product 7. The process for producing mineral wool insulation in board form possessing a low density of between about 6 and 25 pounds per cubic foot high strength fire resistance and waterproofness which comprises mixing with water nodulized mineral wool bentonite and a synthetic thermosetting condensation product selected from the group consisting of formaldehyde resorcinol aldehyde formaldehyde and formaldehyde condensation products to provide a suspension in which the concentration of bentonite is between about % and about 18 by weight and of condensation product b^ - tween 14 and about 20 by weight continuously feeding said suspension to a continuously moving screen drawing water containing bentonite and condensation product from said suspension through said screen whereb^ the mineral wool fibres with which bentonite and con densation product in intimate mixture with each other are associated are felted into a thick sheet drying and heat- ing said sheet to convert the condensation product therein into the insoluble infusible state and recirculating said drawn water for use in the process alkali met^ l 8. The process of claim 7 wherein a solubl~ alkali met^ l polyphosphate is present in the suspension condensation 9. The process of claim 7 wherein said condensation product comprises a formaldehyde condensation 60 Froduct 1. The process for producing mineral wel insulation in board form possessing ^ low density of bei rsen^bort References Cited in the file of this patent 6 and 25 pounds per cubic foot high strefnir^gtetsihl- UNITED STATES PATENTS . 1963 water nodulized mineral w^stbentonite and ^ synthetic thermosetting condensation product selected from the 65 group consisting of formaldehyde resorcinol aldehy~ ~formaldehyd^'and formaldehyde condensation products to provide a suspension in which the concentration of benit s bo etwen en i abot ut e % and about % by weight and of condensation product is 70 between about 1 and about % by weighz conticsously feeding said suspension to a continuomuosvlinyg sereen drawing water from said suspensing xough said screen whereby the mineral wool fibres with rhich ben- tonite and condensation product is intimate mixture with 75 737,099 951,183 1,160,365 1,841,678 1,887,726 1,372,493 2,011,915 2,067,876 2,151,357 2,195,272 Hall _________________ Baekeland -_ _________________ Aug. 1963 _____ M ar81910 _ Nov. 16 1915 . Russell Jan. 19 1932 Weber Nov. 15 1992 Aug. 20 Seigle s_. Seigle adsommsbu~ Sept. 4 1934 1933 Campbell ____________ Jen 12 1937 Reitzel ~~ . Mar. 21 1939 Ehlers COLLISION Mar. 26 1940 Cther references on following page Lent Tbyegs ABstecte Tie We ES VIO 7 9 UNITED STATES PATENTS 2,782,298 10 OTHER REFERENCES | i 2,348,804 2,383,066 Gerity McDermott May 16 1944 Manufacture of Pulp and Paper 3rd ed vol V sec 1 ' Aug. 1945 pp 17 107 ts : Ang 2,407,376 Maxwell Sept. 10 1946 Boehm Paper Trade J. May 2 1940 pp 35 36 : 8,186 Miller 1948 Quim et al Oct. m m 2,485,458 Oct. 18 1949 4 2,567,559 Grieder Sept. 11 1951 2,633,453 Hollenberg Mar. 31 1953 . \ \ \ . Ly \ \, i , \ . . gf t. t. L .: i Y. t i t > $ i $ + r . 4 ' t