US2338839A - Method of manufacturing mineral wool products - Google Patents

Description

H. T. COSS Jan. 11, 1944.

METHOD OF MANUFACTURING MINERAL WOOL PRODUCTS Filed NOV. 25 1941 Y mm w NCIR M A w, 0 M W ll llllllll I,

Patented Jan. 11, 1944 UNITED, STATES, "PATENT OFFICE DIETHOD OF MANUFACTURING MINERAL WOOL PRODUCTS Harold T. Coss, Somerville, N. J., assignor to Johns-Manville Corporation, New York, N. Y., a corporation of New York Application November 25, 1941, Serial No. 420,355

13 Claims.

The present invention relates to felted mineralwool products and to a method of making the same and, more particularly, to a process for the manufacture of semi-rigid and rigid mineral wool blankets, batts or blocks. It will be understood that the term mineral woo i employed herein in a generic senseto denote fibres formed from rock, dag, glass and other conventional raw ma-- terials and mixtures'thereof.

In previously proposed methods for the manufacture of materials of the general type here under consideration, molten mineral wool forming material is disintegrated into a multiplicity of fine fibres by a suitable fiberizing means, for example, a steam blast, and the fibres are collected in a blow chamber or the like. A binder is sprayed or otherwise injected into the suspension of fibres adjacent their place of formation. The fibres gather on the floor of the blow chamber, suitably a conveyor, in 'interfelted relationship; with the binder particles uniformly disseminated therethrough. The felt thus formed is carried from the blow chamber and heated to soften the binder where, as is conventional, a thermo-plastic binder is employed, and the felt is then compressed to the desired density and maintain'ed under compression until the binder has cooled and solidified. As will be readily understood, such previously proposed methods have required the use of a relatively expensive cooling and compressing mean due to the fact that the felt must be heldinlits compressed state by externalmeans during the relatively long interval required to cool the binder to solidifying temperaturesf Also, when the finished material is subsequently warmed, as for example, when employed in a position exposed to heat or when hot coatings are applied, such as when the material is used ln built-up roofs, exfoliation takes place due to the releasing ofthe adhesive bondand the consequent expansion of the compressed resilient structure.

An'object of the instant invention is the provision of a. method and product which will overinvention.

Referring now to the drawing and particularly to Fig. 1, there is diagrammaticall shown an apparatus suitable for carrying out the method of the invention. As will be understood, conventional portions of the structure are not shown in detail and may take difierent forms. The apparatus gene'rallycomprises a melting furnace I 0, which ma be'a ,cupola (as illustrated), a tank furnace, or the like, of any conventional design.

The molten material issues from an orifice l2 to fall in the form of a stream into the path of a steam jet or the like M, which hreds it into a reat multiplicity of fibres which are carried by the force of the steam jet and'in gaseous suspension into blow chamber 5.

In accordance with the instant invention,-' a binder is injected into the suspension of fibres adjacent their place of formation, the binder including two distinct components, namely, a thermo-setting material and a thermo-plastic material. I The two materials may be separately injected into the suspension in an suitable manner, for example, as by atomizing binder jets l8 and 20. The thermo-setting material ma suitably be in water solution or suspension, particularly if it is a resin, and the thermoplastic material is preferablyin a heated fluid state.

The thermo-plastic component of the binder preferably is an asphalt or the like of a meltingpoint to be determined by the particular qualities desired in the finished material. However, other relatively inexpensive conventional thermo-plastic binding materials, such as Waxes, asphaltic fluxes or the like may be used. 3

' .Th'e .thermo-setting component of the binder suitably comprises aresin,.such as a commercial phenol'formaldehyde, lignin-furfural, or glyptol resin. However, it will be understood that the invention is in no way limited to the particular heat setting binder employed and that other materlals than those specifically set forth may be employed, for example, an emulsifiable'oil varnish. The binder is employed in suitable pro-' portions depending upon the type of material desired. Where a relatively rigid block or blanket is to be formed, it has been determined that the binder may comprise, for example, between 18 and 24% by weight of the product. However, the proportions of binder may vary between much wider limits, for example, the binder may be present in proportions of from or less to 30% or more. material suitably constitutes the major constituent of the binder. For example, asphalt or the like may preferably comprise from 3 to 30% by weight of the final product and the resin, or

other thermo-setting material, from 2 to 25%.

Preferred proportions, which have been found to form a igid block or blanket which exhibits good strength, waterproofness' and low cost, comprise 2% of the resin and of a230 melting point asphalt.

When found desirable, the thermo-setting resin may be diluted with an conventional distending materials, as, for example, dried blood or starch. The thermo-plastic constituent of the binder may be rendered more fire'retardent by incorporating The relatively inexpensive thermo-plastic therein small amounts of an aromatic chlorinated hydrocarbon material, .such as thematerial sold under the name Halowax. In lieu of the use of Halowax to prevent fires in the blow chamber, water may be employed as disclosed and claimed in the copending application of J. H. Zettel, Serial No. 414,484, filed October 10, 1941.

. Blow chamber 16, which receives the suspension of fibres and minute binder particles includes a bottom wall, preferably comprising a continuously moving endless belt or conveyor 22, traveling in the direction indicated by the arrow, on which the fibres settle in felted relationship with the binder particles disseminated substantially uniformly throughout the felt. As willbe understood, due 'to the relatively small volume of binder, the porosity of the felt will not be affected to any appreciable extent and the felt will retain its insulating function. The felted mass of fibres is carried from the blow chamber by the conveyor and preferably is compacted to some extent to form a relatively thick blanket 24 by press roll 26 at the exit end of the conveyor. The rate of the movement of the conveyor 20 may be correlated to the rate of deposition of the fibres to obtain a uniform andidesired density of the product, for example, by means of a weighing scale 28, over which the felt passes. The scale is operatively connected to the drive of conveyor 22 by any suitable means whereby increase -in the weight of the blanket increases 'thespeed of movement of the conveyor and vice versa.

' The blanket passes from scale 28 between endless conveyor belts 30 driven over suitable pulleys 32 in the direction indicated by the arrows. In the'preferred form, conveyors Mare made up of a plurality of'relatively rigid hingedly connected plates or flights reinforced. against yielding duringthe compressing operation as by flanges 52. The flights are perforated to permit the passage of a heating medium therethrough.

' It will be understood, however, that'other types of conveyors may be employedwhich have sumdevice, as indicated at 33. The conveyors 30, or at least their adjacent reaches, are surrounded by a suitablehousing 34'enclosing the greater proportion of the length of the belts and forming a heating oven. Air at a temperature say between 300 and 400 F., depending upon the setting temperature of the particular resin employed, is circulated from any suitable heating means, such as furnace 36 through ducts 38 opening into the housing ve and below the' adjacent reaches of ti" conveyor and is forced through the conve' ,rs and the blankets held therebetween. The upper conveyor 30 is adjusted relatively to the lower conveyor by means 33 to compress the blanket to the desired finished thickness.

When the blanket leaves conveyors 30, the thermo-setting component of the binder has been set and, in consequence, the blanket retains its compressed state, although the thermo-plastic component is in a non-binding condition. ,The blanket then passes to a suitable cooling device which may be but a single foraminous conveyor 40 supported by pulleys 42. Preferably located below the conveyor is a suction box, asindicated at 44, connected to any suitable suction device (not shown) whereby air at room temperature is drawn through the felt to cool the same and harden the thermo-plastic component of the binder. The cooled blanket may be transferred from conveyor 40 to any suitable or conventional cutting and slitting means (not shown) to divide the same into units of the desired size.

It has been determined that blankets or blocks made by the process described above have a strength, waterproofness, andrigidity superior to those employing a heat setting binder alone, unless a prohibitively expensive amount of the amount of the binder is used, and have a resistance to softening and exfoliation under high temperatures far superior to products employing or other .thermo-plastics, as the only asphalt, binder.

Having thus described .my invention in rather full detail, it will be understood that the details need not be strictly adhered to but thatvarious changes and. modifications will suggest themselves to one skilled in the art, all falling within stantially uniformly distributing a binder therethrough, said binder including a thermo-plastic material and a thermo-setting material, compressing the felt to substantially the desired finished thickness while simultaneouslyheating said felt to a. temperature to set said thermo-setting binder, and cooling said felt to set said thermoplastic binder.

-' 2. The method comprising forming a suspen- I sion of mineral wool fibres and a binder distributed there throughout, said binder including a major proportion of a thermo-plastic material and a. minor proportion of a thermo-setting niaterial, forming a felt from said fibres with the binder substantially uniformly disseminated therethrough; compressing the felt to substantially the desired finished thickness while simul taneously heating said felt to a temperature to set said thermo-setting binder, and cooling said felt to set said thermo-plastic binder.

3; The method forming a felt of mineral wool fibres and subcomprising simultaneously I mineral wool fibres stantially uniformly distributing a binder therethrough, said binder including a major proportion of a thermo-plastic material and a minor proportion of a thermo-setting material, compressing the felt to substantially the desired finished thickness while simultaneously heating said felt to a temperature to set said thermo-setting material by the circulation of heated air therethrough, and cooling said felt to harden said plastic material. I v

4. The method comprising simultaneously forming a felt of mineral wool fibres and substantially uniformly distributing a binder therethrough, said binder -comprising,fby weight of the felt, from 3 to 30 per cent of a thermoplastic material and from 2 to 25 per cent of a thermo-setting resin, compressing said felt to substantially the desired finished thickness while simultaneously heating said felt to a temperature to set said thermo-setting resin, and thereafter cooling said felt to harden said thermo-plastic material.

5. The method forming a felt of mineral wool fibres and substantially uniformly distributing a binder'therethrough, said binder felt, from 3 to 30 per cent of an asphaltic material and 2 to 25 per cent of a' lignin-furfural resin, compressing said felt to substantially the desired finished thickness while simultaneously heating said felt to a temperature between 300 and 400 F. for a period suflicien't to set said resin, and thereafter cooling said felt to substantially room temperature to harden said asphaltic material.

s. The method comprising simultaneously forming a felt of mineral wool fibres and substantially uniformly through, said binder distributing a binder therecomprising, by weight of the felt, from 3 to 30 per cent of a the'rmo-plastic material and from 2 to 25 per cent of a thermosetting resin, diluted with a distending material, compressingsaid felt to substantiallythe desired finished thickness while simultaneously heating said felt to a temperature to set said thermo-setting resin, and thereafter cooling said felt to harden said thermo-plastic material.

'7. An insulating material comprising a felt of compressed into blanket or having disseminated therebinder comprising a major batt form, said felt through a hardened into blanket or comprising simultaneously comprising, by weight of the proportion of a thermo-plastic material and a minor proportion of a thermo-settmaterial, said binder being present in such proportion as to felt.

8. An insulating. article of manufacture comprising a felt of mineral wool fibres compressed into blanket or batt form, said felt having disseminated therethrough a binder comprising from 2 to 25 per cent by weight of the product of a thermo-set resin and from 3 to 30 per cent by weight of the product of a thermo-plastic material, the thermo-set resin constituting a minor proportion of the binder in each instance.

'9. An insulating article ofmanufacture comprisinga felt of mineral wool fibres compressed batt form, said felt having disseminated thereth'rough a thermo-set resin in a proportion of the order of 2% by weight of the product and a thermo-plastic material in a proportion of the order of 15% by weight of the product.

10. An, insulating article of manufacture comprising a felt of mineral wool fibres compressed into blanket or batt form, seminated therethrough a said felt having disbinder comprising asvphalt and a phenol formaldehyde resin, said binder being present in such proportion as to preserve substantiallythenatural porosity of the Y seminated therethrough a binder comprising asphalt and a phenol formaldehyde resin in proportions by weight of the article of 3 to 30 per cent and 2 to 25 per cent respectively, the phenolformaldehyde resin constituting a minor proportion of the binder in each instance.

13. An insulating article of manufacture come prising a felt of mineral wool fibres compressed into blanket or batt form, said felt having disseminated therethrough a binder comprising 38-, phalt and a lignin-furfural resin improportions by weight of the article of 3 to 30 per cent and resin constituting a minor Himonn 'r. coss.

25- per cent respectively, the lignin-furfural

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