US2282230A - Mineral wool product and the method of making it - Google Patents

Description

May 5, 1942. w. M. MacALPlNE MINERAL WOOL ERODUCT AND THE' METHOD OF MAKINGy IT Filed Jan. 25, 195s INVENTOR. Will/'am M. MaC/Hp/'na BYVMXQ. /M

ATTORNEY' Patented May 5,

MINERAL WOOL PRODUCT AND THE f METHOD OF MAKING IT william ML Macmpi'ne, Somerville, N. J., assignor to Johns-Manville Corporation, New York, N. I., a corporation of New York vApplication January 25, 1938, Serial No. 186,819

. Clailms.` This invention relates to a mineral wool product and the method of making it. More pai'-` ticularly, the invention relates to the use of a drying oil binder i a layer of matted mineral wooliibres.

In hardening a drying oil binder in mineral wool products, such as rock, slag, or glass Wool, special difficulties arise. In the rst place, the very large amount of oil surface, due to the oil forming a thin coating over the innumerable iibres, promotes exceedingly quick reaction with the oxygen of the air brought into contactvwith the drying oil at drying temperatures.- In the second place, the thermal insulating effectiveness o a thick layer of mineral'wool tends to preserve within the layer the heat evolved in the reaction of the drying oil with the air. As a result, it is dilcult to set the drying oil at a desirably high temperature and rate and, at the same time, avoid burning or badly scorching the oil, dueto the rise in temperature above that at which the setting is initiated. For instance, the setting of the drying oil binder at an initial temperature of about 400 to 600 F. ordinarily would lead to serious overheating of the drying oil binder, because of the heat evolved during the setting of the binder.

It is an object of the present invention to overv come the diculties encountered in the use of drying oil binders in mineral `wool products. Another object is to provide a mineral wool felt of improved properties and an economical method of producing it. Other objects and advantages reactions are initiated, the large excess of air will appear from the following detailed description.

A preferred embodiment oi.' the `invention will be described in connection with the attached drawing showing diagrammatlcally a side view oi' equipment for effecting the setting of the binder. Other equipment used is conventional and, therefore, not illustrated.

In general, the method is as follows: There is formed a layer or felt of matted-mineral wool libres including the drying oil binder composition distributed over the bres. 'I'he layer` of iibres and binder is then subjected to treatment p to harden (set) the binder under conditions so carefully controlled that the binder may be hardcned at a suillciently elevated temperature to produce the best results while there is prevented additional riseI of the temperature to such point as to produce substantial scorching of the binder. ,The desired results are obtained by forcing through the layer a very large excess of hot air. The hot air initiates and promotes the exo- CAB Cal

thermic reactions of setting, such as oxidation and/or polymerization. Once the reaction or maintains the binder composition at the` desired temperature and carries away heat which is developed by the setting and which, otherwise, would cause scorching. 'I'he setting occurs in a relatively short period of time. l

The invention will be illustrated more speciflcally bythe following detailed example.

There is provided, first of all, a molten silicate lcomposition suitable for use in the manufacture of mineral wool. This molten composition is shredded, as by being caused to fall in the form of avery thin stream into a steam' blast including the selected drying oil binder composition dispersed in the blast.

r There is thus produced an air suspension of fibres coated with the binder composition. The bres and adheriner binder are then collected into a layer on a suitable felting member. This co1- lection may be made (l) on the moving conveyer constituting the floor of a conventional rock wool blow chamber or, preferably, (2) under the influence of suction applied behind as'creen wire or like ielting member. In any case, the fibres are collected into a layer that is relatively thick, say 1/4 inch to e inches or so in thickness.

The felt or layer o! matted fibres thus formed` is then subjected to treatment to set the binder composition therein. Hot air in large excess is passed through the felt. For instance, the felt l is confined between screen or other air-permeable members 2 and 3, disposed on opposite faces of the felt and, suitably, pressed thereagainst by pressure applied between theskeleton supports i and 5 whereby the thickness of the fibrous layer is established during the setting operation. Preheated hot air is supplied through the line 6, and is passed through the portion of the felt to the right in the drawing, the ail` being mixed with a predetermined amount of additional hot air in the blower 1, and returned through line 8 to the drier proper and then passed'through the portion of the felt at the ting of the binder and at no time is so high as lto produce substantial scorching of the binder,

by which term is meant thermal decomposition with objectionable loss of strength, toughness, or

`resiliency of the binder.

Because these temperatures are dangerously near the temperature of scorching ofthe binder composition, it is important that some means be provided for rapid cooling to offset lthe heat developed by the reactions accompanying the setting. For this purpose, there is used an amount of air largely in excess of that required lto oxidize the drying oil binder. .Advantageously,

the amount of air admitted through line 6 diluted ment, is such that there is no large rise in temperature of the air passing through the felt. For

instance, there have been used linear vvelocities of air through `the felt, in the direction from face to back thereof, of the order of 30 to 100 feet a `minute. Air at such a velocity effects the desired cooling and, on the other hand, does'not cause blowing oriibres from the felt or .roughening of it to an objectionable extent. In general, the temperature used and the amount of air blown 1 through should be such as to give a'quick oxida ,tion and/or polymerization of the drying oil, l ywith the elimination of compounds of objection- Vable odor. Thus,. there are used to advantage a total setting time of the order of 1 to 10 minutes. Due to the shortness of this time period, the pos- `sibility of undesired side reactions occurring at the prevailing high temperatures is minimized.

There maybe used, for instance, about 1,000

to 4;000 cubic feet of air (measured at standard pressure and temperature conditions, namely, 760

, `somewhat by leaks around the edges of the equipkerosene has been separated and which remains as stock for the manufacturing of lubricating oil.

In general, the hardening and the plasticizing agent selected should be freely soluble in the drying oil used, water-repellent, practically nonvolatile under all conditions of use, and resistant to decomposition at all temperatures to which the mineral wool is exposed during the manufacture of the product of the present invention.

The binder composition, suitably, includes a conventional drier for the drying oil that is oil` soluble, as, for instance, lead, manganese, cobalt, or iron naphthenates'or resinates. The proportion of drier may be'varied within limits but is preferably about 0.3 to 1 part to 100 parts of the drying oil. Preferably, also, the drier as used is a mixture of two or more of the individual driers above. u

Following are illustrative formulae for the binder composition, the proportions being given as parts by weight:

. Example Il Drying oil l 80 plasticizer 30 Driers 0.5

Example II Drying ou a0 Gusonite a Plasticizer 4 Driers 0.3

mm; of mercury and c'C.) for each pound of drying oil in the binder.

There may be'used various drying oils, as, for

` example, linseed, perilla, oiticica, and hempseed. However, perilla oil, either alone or mixed with moderate proportions of one of the other drying 1 oils, has been found to give outstanding results.

In making a mineral wool product that is to be mixed with a hardening agent. On the other "hand, a plasticizing agent may be used to make a softer or more flexible felt. -As a matter of relatively rigid and resilient, such as a felt for lining automobile bodies or the metal cases of electric refrigerators, the drying oil is preferably economy, there may be used, in many cases, a

` hardening and a softening agent; in this way the amount of the rather expensive drying oil maybe decreased by substitution of cheaper materials, without development of either i like.

Plasticizing agents that may be used are a semidrying oil, such as fish oil or soya bean oil, 1 asphaltic fluxes characterized-by relatively low temperature of softening and high penetration,

and/ or a petroleum oil that is miscible in all proportions with the drying oil, is a liquid' at normal temperatures, and is practically nonvolatile at 500 F, Such a petroleum plasticizer is the fraction of Pennsylvania oil from which The proportion of drying oil is usually about half or more of the total composition, the other ingredients being varied to give the hardness, rate of oxidation, or waterproofness desired.

While the drying oil itself is somewhat waterrepellerlt, greater resistance to wetting by water is imparted by the hardening or plasticizng agent used.

Mineral w-ool products including a small pro portion of the binder compositions recited above, say, in the proportions of l to 6 parts binder to parts total weight of the products, not only permit setting of the binder without overheating but also are not readily combustible in the finished form. In fact, products so made do' not carry a flame and do not continue to smoulder after being exposed for a short time to the flame of a gas burner.

On the other hand, the products are coherent,v somewhat sprin'gy and resilient, and of very low density, the density varying somewhat with the amount of pressure, if any, applied 'to the layer of matted bres during the step of setting the binder.

When the drying oil is introduced into the,

blast of steam before the steam strikes the molten mineralwool composition and berizes it, a particular effectof the drying oil is noted. The application of the drying oil in this manner, for

some unexplained reason, promotes the formation of longer libres, less dust, and better matting or felting than is the case if other binder` is used or if the drying oil is applied subsequent to the blast becomes distributed over a large part of the 1 total surface of the mineral wool fibres.` However, the term "coating or coated aslapplied i to the binder composition is intended to include a flhn extendingeither continuously ory discontinuously over the exterior portions of the bres.

aaeaeeo required to set the drying oil, the temperature within the said layer being maintained during the passage oi the air at a maximum temperature above 500 F. and below the temperature of substantial scorchingoi the drying oil. l

2. The method of making a mineral wool product which comprises forminga thick layer, lncluding matted mineral wool 4fibres and a drying oil binder distributed thereover,` and passing a large excess of warm air through the said layer. while maintaining thereina temperature of the order of 500 F. i

3. The method of making a mineral wool product which comprises forming a thick layer, including matted mineral wool libres and a drying oil binder distributed thereover, and passing preheated air through the said layer at an average linear velocity ofthe ordex` of 30 to 100 feet per minute, the maximum temperature within the layer being maintained abovev 500 F. and below the temperature of substantial scorching of the drying oil binder.

fi. 'Ihe method of making a mineral wool product which comprises forming a thick` layer, in;- cluding matted mineral wool bres and a drying oil binder distributed thereover, and passingfa large excess of preheated air through the layer,

the said layer being maintained during the treatment with air at a maximum temperature of the mately the maximum vtemperature being condrying oil substantially 'completely but not in excess of 20 minutes'.

5. An article of manufacture comprising a layer of matted mineral wool fibres and a binder distributed thereover, the binder consisting chiefly of perilla oil in set condition and being ln the proportion of 1 to 6 parts to 100 parts total Weight of the article.

6. An article of manufacture comprising a layer I of matted mineral wool fibres and a binder distributed thereover, the binder consisting chiefly of oiticica oil in set condition and being in the proportion of 1 to 6 parts to 100 parts total weight of the article.

7. An article of manufacture comprising a layer of-y mineral wool fibres andabinder distributed throughout said layer. the binder comprising perilla oil in set condition and la. hardening agent, the proportion of the binder composition being 1 to 6 parts to 100 parts total weight of the article.

8. An article of manufacture -comprising a layer of mineral wool fibres'and a binder distributed throughout said layer, the binder comprising perilla oil in set condition and a plasticizing agent, the proportion of the binder composition being 1 to 6 parts to 100 parts total weight of the article;

9. 'I'he method of making a mineral wool product comprising forming a felted layerl including mineral wool fibres and a binder-,composed principauy of perilla oil distributedl thereover, and passing a large excess of warm air through said layer while maintaining therein a temperature torapidly harden said oil.

10. The method of making a mineral Wool product which comprises forming a thick layer, including felted mineral Wool fibres and a drying oil binder distributed thereon, and passing air through said layer in an amount greatly in excess of that required to set the drying oil, while mainorder of 600 F.' and the treatment at approxitinued for a period of time adequate to set the` taining in said layer a temperature of the order of 400 to 600 F.

WILLIAM M. MAcALPINE.

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