WO1990007473A1

WO1990007473A1 - Fire-resistant glass fibers, structures employing such glass fibers ans processes for forming same

Info

Publication number: WO1990007473A1
Application number: PCT/US1988/004648
Authority: WO
Inventors: Carl R. Strauss; Richard D. Godfrey; Steven D. Crothers; Beverly A. Goudy
Original assignee: Owens-Corning Fiberglas Corporation
Priority date: 1988-12-27
Filing date: 1988-12-27
Publication date: 1990-07-12

Abstract

Glass fiber septa (30) and insulation product (36) containing septa (30) between two glass wool layers (24) are treated, and thus rendered fire-resistant, by placing a phosphate-containing compound onto or in close proximity to the glass fibers. The phosphate-containing compound relases phosphoric acid when thermally degraded to form a protective silicate phosphate ceramic coating on the surface of the fibers. Exemplary phosphate-containing compounds are mono and diammonium phosphates, dicalcium phosphate, monocalcium phosphate, phosphoric acid, aluminum phosphate, and mixtures thereof.

Description

D E ^S C R I P I ^O N FIRE-RESISTANT GLASS FIBERS, STRUCTURES EMPLOYING SUCH GLASS FIBERS

AND PROCESSES FOR FORMING SAME FIELD OF THE INVENTION This invention relates to fire-resistant glass fibers and, more particularly, to structures which employ such fire-resistant glass fibers, (such as glass wool, glass fiber mats, and the like), the fire-resistant glass fiber structures of the invention being especially well suited for use as building insulation.

BACKGROUND AND SUMMARY OF THE INVENTION Fire-resistant products are continually being sought for use in the building industry due to their obvious benefits of reducing the building occupants' risk of injury during fires. The theory behind the use of fire-resistant building materials is, of course, that such materials afford the building occupants more time to safely evacuate a burning building. While buildings typically now include a batting of glass wool in interior wall cavities for the purpose of providing acoustical insulating properties, what has been needed is a glass wool insulation which not only provides normal acoustical insulation properties, but which also is fire-resistant. It is towards the achievement of such a product that the present invention is directed.

According to this invention, it has been discovered that when an effective amount of a phosphate-containing compound (to be defined later) is brought into close proximity and/or contact with the surface of a glass fiber, and when the thus treated glass fiber is exposed to temperatures well in excess of those which would normally melt an untreated fiber (e.g. , temperatures in excess of about 649^βC (1200^βF), the fiber nonetheless surprisingly withstands such elevated temperatures for significant time periods without melting.

What has been found according to the invention is that those phosphate-containing compounds which release phosphoric acid upon thermal degradation produce a phenomenon whereby the released phosphoric acid apparently will migrate to the surfaces of glass fibers in close proximity and/or contact therewith where it reacts with the silica constituent of the glass to form a protective silicate phosphate ceramic coating or layer on the glass fiber surfaces. In fact, for certain phosphate-containing compounds, this migration phenomenon has been observed to, in effect, spread the protective ceramic coating to glass fibers not actually in contact with, but in sufficiently close proximity to, the phosphate-containing compounds. It is this protective ceramic coating (as confirmed by X-ray diffraction analysis) that apparently renders the glass fibers, glass wool, and glass mats of the invention capable of surprisingly withstanding the temperatures of an open flame for a significant period of time. For example, it has been found that glass wool of this invention apparently achieves equilibrium when exposed to an open flame such that the glass wool does not "burn through" even after flame exposure times in excess of one hour.

The phosphate-containing compound can be brought into close proximity and/or contact with glass fibers in any convenient manner, such as spraying, dipping, sprinkling or padding. For example, when the glass fibers are formed into a glass wool, an aqueous solution of the phosphate-containing compound may be conveniently sprayed via a conventional spray ring onto the glass fibers prior to their collection on a conveyor to form the glass wool. The phosphate-containing compound may also be applied onto the glass fibers concurrently with an aqueous glass wool binder solution, in which case, the phosphate-containing compound is added to the binder solution prior to application.

In a particularly preferred technique, glass wool is bisected at or near its midplane after formation and curing to form two glass wool layers of substantially equal thicknesses between which a septum or substrate carrying the phosphate-containing compound is interposed. Thus, when the layers are brought into contact with respective surfaces of the septum, a composite "sandwich" structure is formed comprised of the two glass wool layers and an interlayer comprised of the treated septum. A particularly preferred septum is a wet-laid nonwoven glass mat on which a coating of the phosphate-containing compound has previously been applied.

^~ The fire-resistant glass fibers of the present invention may be embodied in a variety of structural forms, the presently preferred examples of which are glass wool, glass mats and composite structures formed of such glass wool and mats which are useful as building insulation.

-^**•" Accordingly, while reference has been, and will hereinafter be, made to glass wool, glass fiber mats, and building insulation products employing the same, it should be understood that such references are intended to identify presently preferred embodiments of, and utilities for, this 5 invention and, therefore, are intended to be nonlimiting. Other advantages and uses of this invention will become apparent to those skilled in this art after careful consideration is given to the following detailed description. 0

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Reference will be made to the accompanying drawings wherein:

FIGURE 1 is a schematic representation of a system for 5 forming fire-resistant glass wool insulation product of this invention; ¹ FIGURE 2 is a schematic cross-sectional view of one form of the fire-resistant glass wool insulation product of this invention; and

FIGURE 3 is a schematic cross-sectional view of another - form of the fire-resistant glass wool insulation product of this invention.

DETAILED DESCRIPTION OF THE INVENTION As used herein and in the accompanying claims, the term "phosphate-containing compound" is meant to refer to a ° phosphate-containing compound which releases phosphoric acid upon thermal degradation and thereafter reacts with silica on the surface of glass so as to form a silicate phosphate ceramic compound (for example, a silicate orthophosphate compound or a silicate pyrophosphate compound) on the glass l^ surface. Exemplary phosphate-containing compounds within the scope of this definition, and which are thus useful for the practice of this invention, include monoammonium phosphate, diammonium phosphate, dicalcium phosphate, monocalcium phosphate, phosphoric acid, aluminum phosphate,

20 and mixtures thereof.

The glass fibers with which the phosphate-containing compound may be employed can be formed of any glass. For example, the glass fibers employed in forming the fire-resistant glass wool of the invention may be composed

25 of standard insulation-grade wool glass. When utilizing a glass "shingle mat" as a septum for the phosphate-containing compound, the mat is preferably of a non-woven, wet-laid variety, but woven forms thereof may also be employed. Preferably, the mat is comprised of E-tγpe glass but other

30 glass types may be employed. The septum may also be formed of any other woven or nonwoven material, for example, kraft paper, wire mesh^* screen, etcetera, as long as it exhibits sufficient structural integrity to carry the phosphate-containing compound.

35 Presently, the preferred fire-resistant insulation structure of this invention will include a wet-laid nonwoven glass mat treated with dicalcium phosphate and interposed between two layers of glass wool. This preferred form of the invention exhibits the surprising property of dimensional stability at temperatures of up to at least 927°C (1700°F) in addition to elevated melting temperature. The result is a non-shrinking flame barrier which synergistically cooperates with the glass wool to provide a superior performing composite structure in insulated wall applications.

Although not absolutely required, the phosphate-containing compound may be admixed with a silica to assist in the formation of a silicate phosphate ceramic coating, one preferred example of which is Ludox AS-40 (Dupont) . When used in admixture with a binder solution for glass wool, it is preferred to use a colloidal silica

- - suspension to facilitate dispersion in an aqueous binder system.

The phosphate-containing compound must be applied in sufficient amount to impart fire-resistant properties. It has been found, for example, that the fire-resistance 0 properities of glass wool are enhanced with increased amounts of phosphate-containing compound up to a plateau level above which only marginal fire-resistance enhancement properties are observed. Preferably, the phosphate-containing compounds are applied to glass wool (or 5 to a septum in contact with the glass wool) in an amount greater than 14.7 (.30 pounds) (more preferably, 17.1 (.35 pounds)) grams (pounds) of elemental phosphorus per square meter of the substrate on which the compound is applied (e.g. the glass wool, glass mat septum, etc.). As a 0 specific example, when a mixture having a 63/37 weight proportion of monoammonium phosphate/diammonium phosphate is utilized, the mixture is preferably employed in an amount greater than about 69 grams of the mixture per square meter (1.4 pounds of the mixture per 100 square feet), and more 5 preferably within the range of about 69 to 88 grams of the mixture per square meter (1.4 to 1.8 pounds of the mixture per 100 square feet). Moreover, when dicalcium phosphate is ^•- employed, it is preferred to use an amount greater than about 98 grams per square meter (2.0 pounds per square feet) and, more preferably, within the range of about 98 to 127 grams per square meter (2.0 to 2.6 pounds per 100 square ⁵ feet).

A presently preferred system for producing fire-resistant glass wool for building insulation is shown in accompanying Figure 1. As is well known per se, a glass wool 10 comprised of attenuated glass filaments formed via

^•■-0 spinners 12 is collected upon a continuous belt conveyor 14. The spinners 12 include perforated cylindrical walls so that when the spinners rotate, molten glass supplied to spinners 12 will pass through the perforations thereby forming a glass filament veil (noted by dashed line 15 in Figure 1)

^"-^■ within forming hood 16. The formed filaments thus collect upon conveyor 14 moving in the direction of arrow 14a. Preferably, a glass wool binder composition (of any variety well known to those in this art) is sprayed onto the surfaces of the formed glass fibers via spray rings 17

20 associated with each spinner 12.

The uncured glass wool 10 is then introduced into an oven 18 whereby the binder solution is cured to impart structural integrity to the batting. The cured batting (now designated by reference numeral 20) exits oven 18 and, in a

25 particularly preferred embodiment of this invention, is longitudinally bisected at its midplane (or at any other desired horizontal plane) via a reciprocating knife or continuous band saw 22 so as to form upper and lower glass wool layers 24, 26, respectively. After the bisecting

30 operation, layers 24, and 26 are separated from one another via suitable guide rolls 28.

A septum layer 30 which carries a previously applied phosphate-containing compound in accordance with this invention is directed from a supply roll 32 at right angles

35 to the path of conveyance of glass wool 10 and is redirected via suitable turning rolls (schematically shown at reference numeral 34. in Figure 1) so as to be interposed between layers 24 and 26. A suitable adhesive (for example, an aqueous latex or hot melt) is preferably applied to the inner surfaces 24a, 26a of layers 24 and 26, respectively, so that when layers 24, 26 are brought into contact with septum 30, a composite "sandwich" structure (noted by reference numeral 36) is formed. Although the insulation structure 36 is preferably "unfaced" when employed in interior wall cavities, a backing layer or facing of paper or metal foil 38 may be applied from a supply reel 40 thereof, particularly if the structure 36 is to be used in an exterior wall cavity.

The resulting insulation structure 36 (absent facing

38) is shown more clearly in Figure 2 (the layers thereof being shown in greatly enlarged manner for clarity of presentation) . As is seen, the insulation structure 36 is composed of glass wool layers 24 and 26 with septum 30 interposed therebetween. Preferably, septum 30 is a nonwoven, wet-laid "shingle mat" formed of E-type glass filaments. However, any other material may be employed as septum 30, for example, kraft paper, wire mesh screen, etcetera, as long as it is capable of "carrying" the phosphate-containing compound and is compatible with the particular phosphate-containing compound(s) being used. For example, when dicalcium phosphate is used, it is important that it be carried by a glass fiber mat since the dicalcium phosphate-treated mat has been observed to be a substantially nonshrinking fire-resistant barrier per se.

If the phosphate-containing compound is in the form of a substantially water-insoluble solid particulate, it is also preferable to apply a tackifying agent, such as polyvinyl alcohol, latex adhesive, etc., to the septum so that the compound remains evenly dispersed on the septum's surface during processing and/or handling. If the phosphate-containing compound is in the form of a water-soluble solid particulate, it is most conveniently applied to the septum by spraying, dipping, etc. in the form δ

of an aqueous solution followed by drying so as to leave a residue of the phosphate-containing compound thereon.

As an alternative for interposing septum 30 between layers 24 and 26 of batting 10, the phosphate-containing compound may be sprayed, coated, sprinkled, or otherwise applied to one or both of the surfaces 24a, 26a of layers 24, 26, respectively, as is shown schematically by nozzle 42 in Figure 1. The compound(s) may also be sprayed, coated, sprinkled, or otherwise applied to either exterior surface of the unσured or cured batting 10, 20, respectively (as shown, for example, by impregnated layer 44 in Figure 3). In yet another alternative, the phosphate-containing compound may be placed in solution with a glass wool binder, the binder/phosphate-containing compound solution thereby being sprayed concurrently via spray rings 17. In such a case, the entire thickness of batting 10 will be impregnated with the phosphate-containing compound since the individual fibers thereof will be coated during their formation via the spinners 12. Of course, an additional series of spray rings could be employed downstream of spray rings 17 for the dedicated purpose of applying the phosphate-containing compound and the binder solution separately. In this alternative, the phosphate-containing compound is preferably applied to the glass fibers in an aqueous solution, so that upon drying, a residue of the compound remains on the fiber's surface. However, the phosphate-containing compound may also be sprinkled onto the fibers if in a dry, particulate form.

Although mention has been made to alternative methods of forming fire-resistant glass fiber structures such as glass wool, glass mats, etcetera, by bringing the phosphate containing compound(s) into direct contact with the glass fibers, it is only necessary for certain phosphate-containing compounds employed in the practice of this invention to be in sufficiently close proximity to the glass fibers to permit the phosphoric acid which is released upon thermal degradation of the compound to migrate to those 1¹ glass fibers in its vi.ci.nity and react with the silica therein to form the silicate phosphate ceramic as previously described. Thus, for example, it has been found that when a nonwoven glass septum treated with a sufficient amount of certain phosphate-containing compounds (e.g. monoammonium phosphate and diammonium phosphate) is interposed between upper and lower glass wool batting layers, and when the thus formed structure is exposed to temperatures in excess of those normally melting the glass wool (e.g. in excess of ¹⁰ 649°C (1200°F), the formation of silicate phosphate ceramic surprisingly extends outwardly from the septum and into each of the adjacent glass wool batting layers. Therefore, as used herein, the term "close proximity" is intended to encompass the phosphate-containing compound being in

- physical contact with and/or sufficiently physically close to glass fibers to permit phosphoric acid to migrate to the fibers' surfaces when the phosphate-containing compound is thermally decomposed so as to form a silicate phosphate ceramic on the fibers' surfaces. The following nonlimiting examples will provide a further understanding of the invention.

EXAMPLE I Samples representative of an insulated wall cavity were exposed to an ASTM E-119 time/temperature environment. The 5 samples consisted of three layers: (1) 1.27cm (1/2-inch) Type X gypsum board; (2) 9.21cm (3 5/8-inch) , 0.5 pcf, R-ll fiberglass insulation; and, (3) 8.01 Kg per cubic meter (1/2-inch) Type X gypsum board. The insulation in one sample contained a septum treated with a fire resistant 0 additive (FRA) located at the midplane of the insulation. The septum was composed of a 78 grams per square meter (1.6 pound per 100 square foot) glass fiber, wet-laid mat treated with 78 grams per square meter (1.6 pounds per 100 square feet) of a mixture of monoammonium phosphate and diammonium 5 phosphate in weight proportions of 63 to 37, respectively. The insulation was housed in a 0.3 meter by 0.3 meter (1-foot by 1-foot) galvanized metal box with flanges. The - gypsum board was screw-attached to the top (room side) flange. The bottom (fire side) board was supported with wire mesh above the furnace opening.

The three-layer sample was placed over the furnace

5 opening for 50 minutes, and was thereafter lifted to allow the bottom (fire-side) piece of gypsum board to be removed. The sample was then repositioned for an additional 10 minutes so that the insulation was directly exposed to the furnace temperature. The procedure was selected to simulate 0 openings in walls observed in full-scale ASTM E-119 wall tests. Pairs of thermocouples were attached to both sides of the bottom (fire-side) and top (room side) pieces of gypsum board. The time/temperature histories of the top (room-side) surfaces of the gypsum board are listed below in 5 Table 1.

TABLE 1

COMPARISON OF TOP (ROOM-SIDE) GYPSUM BOARD SURFACE THERMAL RESPONSE OF A STANDARD R-ll INSULATED SAMPLE WITH ONE CONTAINING A FRA-TREATED SEPTUM 0 Hot Side Temp, of Cool Side Temp.

Top Board, ^*C (°F) of Top Board, °C (°F)

Time,

Min. Std. FRA-Septum Std. FRA Septum

5 ιo 62(143) 58(137) 39(102) 34(94 20 79(175) 68(154) 53(127) 48(118) 30 154(310) 124(256) 65(149) 61(142) 40 180(356) 158(316) 86(186) 77(171) 50 204(400) 184(363) 91(195) 85(185) 0 55 816(1501) 436(816) 110(230) 97(207) 60 871(1599) 554(1029) 181(357) 105(221)

The above data show that the FRA-treated septum retards the heat flow to the top (room-side) gypsum board throughout 5 the test period. And, especially so, after the bottom

(fire-side) gypsum board was removed at 50 minutes. At the end of 60 minutes, the standard fiberglass batt was completely melted-out of the insulation cavity. For the sample with the treated septum, a midplane barrier was formed. The FRA in the mat appeared to migrate into the fiberglass insulation on either side of the septum when heated to form an approximate 1.3cm (1/2-inch)-thick layer of silicate phosphate ceramic insulation/mat/insulation which provided thermal protection for the top (room-side) gypsum board.

EXAMPLE II Two one-hour wall tests in accordance with ASTM standard E-119 were conducted. In each test, a 3.1 meter x 3.1 meter (10' x 10') partition was prepared consisting of (a) 9.21cm (3 5/8-inch) deep, 0.048cm (0.019-inch) thick, steel studs spaced 61cm (24 inches) on center which are friction fitted between 9.21cm (3 5/8-inch) deep steel top and bottom tracks; (b) 8.89cm (3 1/2-inch) thick, R-1.6 watt/meter-Kelvin (R-ll) glass wool insulation product having a septum of 78 grams (1.6 pound) glass fiber mat located in its midplane; and (c) 1.27cm (1/2-inch) thick

Type X gypsum wall board placed vertically over the studs and fastened with 2.54cm (one inch) Type S drywall screws spaced 30.5cm (12-inch) o.c. in the field and 20.3cm (8-inch) o.c. at the joints, the joints being taped and coated, along with the screw heads, with joint cement. The septum for the first test was treated with 157 grams (3.2 pounds) of a fire retardant additive (FRA) per square meter (100 square feet) while the septum for the second test was treated with 69 grams (1.4 pounds) of FRA per square meter (per 100 square feet). In each test, the FRA consisted of a 63/37 weight proportion of monoammonium phosphate/diammonium phosphate. The results appear below in Table 2:

Table 2 RESULTS OF ONE-HOUR E-119 WALL TESTS FRA amt. grams/m2 E-119

2 Test No. (lbs/lOOFt ) Endurance Pass/Fail pass

fail

^b The "failure" of test number 2 was apparently caused by lateral shrinkage resulting in a void space on or near a stud which, in turn, led to increased local heat transfer. The thermocouple positioned nearest the stud therefore recorded a temperature at 57 minutes, 30 seconds in excess

^**° of the maximum single temperature allowed by ASTM E-119.

Similar shrinkage was observed in Test No. 1, but it did not lead to failure prior to 1 hour. Failure of the sample of Test No. 1, however, occurred shortly thereafter at 61 minutes, 30 seconds. Notwithstanding this, these tests

*- dramatically show the effect of this invention since an untreated glass wool R-1.6 watt/meter-Kelvin (R-ll) insulation product in a similarly configured partition lasts for only between 45 to 50 minutes when subjected to ASTM E-119 testing.

20 EXAMPLE III

The following phosphate-containing compounds were screened for possible fire retardant properties: Dicalcium Phosphate (CaHPO.) Monocalcium Phosphate (Ca(H₂P0₄) "H-O)

25 phosphoric Acid (H-jPO.)

Aluminum Phosphate (Al(H_P0₄)₃-i-xH₂0) Dipotassium Hydrogen Phosphate (K-HPO.) Sodium Phosphate Dibasic (Na₂HP0₄ ^*7H₂0)

Solutions of 50% by weight of each phosphate-containing

30 compound (except dicalcium phosphate which was 25% by weight of an aqueous slurry) were applied onto a "shingle mat" (i.e. an E-tγpe glass fiber wet-laid nonwoven mat) and each mat was then dried in a conventional oven at 150°C. The dried and treated mats were then subjected to laboratory

35 burn-through screening tests in which the mats were subjected to an open flame for arbitrary time periods. Those treated mats which did not burn through after being subjected to the flame for a period of time significantly in excess of one minute were deemed to be suitable phosphate-containing compounds in accordance with this invention since untreated mats would have burned through in only a few seconds (e.g. less than about 5 seconds). The following observations were made:

Compound Observations

Dicalcium Phosphate No burn through at 60 minutes.

Monocalciu Phosphate Ditto at 20 mins.

4Phosporic Acid Ditto at 30 mins.

Aluminum Phosphate Ditto at 30 mins.

Dipotassium Hydrogen

Phosphate Burn through <1 min.

Sodium Phosphate Dibasic Burn through <1 min.

The above observations show that whereas dicalcium phosphate, monocalcium phosphate, phosphoric acid and aluminum phosphate impart fire-resistant properties to glass fibers (and hence may be used in accordance with this invention) , dipotassium hydrogen phosphate and sodium phosphate dibasic do not.

EXAMPLE IV Samples representative of the region around the stud in a gypsum faced, insulated galvanized steel stud wall were exposed to a constant temperature of 927°C (1700°F) on one face. The samples consisted of the following three layers: 1. Two pieces of 1.27cm (1/2-inch) Type X gypsum board, butt-joined over a steel stud; 2. Two pieces of 9.21cm (3 5/8-inch), 8.01 Kg per cubic meter (0.5 pcf), R-1.6 watt/meter-kelvin (R-ll) fiberglass insulation with treated septum on either side of the steel stud; and 3. One piece of 1.27cm (1/2-inch) Type X gypsum board.

The insulation/steel stud assembly was housed in a 0.3 meter by 0.3 meter (1 ft x 1 ft) galvanized steel test box with flanges. The gypsum board was screw- ttached to the flanges of the test box and to the galvanized steel stud crossing from side-to-side dividing the box into two approximately equal compartments.

Both sets of insulation samples contained septa treated with fire-resistant additives (FRA) located at the midplane of the insulation. The septa for one set was composed of 78 grams per square meter (1/6 pound per 100 square feet) glass fiber, wet-laid mat treated with 69 grams per square meter (1.4 pounds per 100-square-feet) of a mixture of monoammonium phosphate and diamonium phosphate (MAP/DAP) in weight proportions of 63 to 37, respectively. The instrumented set of septa were made with the same glass mat but were treated with 103 grams per square meter

(2.1-pounds-per-lOO-sguare-feet) of dicalcium phosphate.

The room side gypsum surface was instrumented with four

(4) thermocouples located 7.66cm (three (3) inches) from the center of the specimen. Two were located over the stud.

Two were located on either side of the stud. Each thermocouple was covered with an insulating pad.

The furnace was pre-heated to 927^βc (1700^βF) and the specimens were positioned with the gypsum joint facing the furnace in a downward position. The instrumented gypsum face was oriented upwardly toward the room. The temperature in the furnace was held constant at

927^βc (1700^βF), and the temperature on the room side gypsum surface was recorded for an hour. In every case, the temperatures over the stud exceeded those adjacent to the stud. Table 3 below lists the highest temperature recorded for each specimen.

Table 3

HIGHEST GYPSUM SURFACE TEMPERATURE RECORD OVER THE

STUD FOR TWO TYPES OF FIRE RESISTANT ADDITIVE

TREATED GLASS MAT SEPTA,°C (°F)

Time Ammonium Phosphate Mixture Dicalcium Phosphate Mins. No. 1-3 No. 1-4 No.2-3 No. 2-4

These data show that specimens containing septa treated - with dicalcium phosphate result in lower maximum gypsum surface temperatures in the critical time period beyond forty (40) minutes.

In all cases the butt-joint on the fire side opened to approximately 1.0cm (3/8 inch) allowing hot furnace gases to - ^ impinge on the insulation septum sandwich. For the ammonium phosphate treated septa, an over-crust of modified wool batting was formed over the treated mat. However, near the stud, wool batting and mat erosion were noted as being approximately 1.0cm (3/8 inch). For the dicalcium phosphate-treated specimens, the wool batting around the stud was melted back approximately 3.8cm (1-1/2 inches) exposing the treated mat which remained flush against the stud.

It appeared that the dicalcium phosphate treated mat 5 had not shrunk even though exposed to temperatures approaching 927"C (1700^βF), thus providing a flame barrier and protecting the wool batting above. For the ammonium phosphate specimen, more beneficial outgasing of phosphate-containing compounds occurred but erosion near the 0 stud appears to have allowed the hot gases to by-pass the mat to the room-side wool batting and adjacent stud.

EXAMPLE V Example IV was repeated with the exception that the steel stud was not present in the test box. The samples 5 were otherwise exposed to the same environment as in Example IV. Upon completion of the tests, the mats were removed and their widths measured. It was observed that those mats treated with ammonium phosphate shrank approximately 3% as compared to their original widths while no shrinkage was observed for those mats treated with dicalcium phosphate.

The observations of Examples IV and V suggest that the non-shrinking dicacium phosphate treated mat performs better than the ammonium phosphate treated mat in the region of the stud although formation of silicate phosphate ceramic in the adjacent wool batting due to migration is apparently diminished with use of dicalcium phosphate.

EXAMPLE VI

Equivalent 8.9cm (3 1/2") thick layers of (1) an "experimental sample" of standard R-1.6 watt/meter-kelvin (R-ll) glass wool insulation product impregnated with an additive of 50/30/20 (parts by weight) composition of MAP/DAP/Si0₂ (MAP = monoammonium phosphate; DAP = diammonium phosphate; i0₂ = colloidal silica, Ludox AS-40, DuPont) at an additive add-on of 49 grams per square meter (1.0 pounds per 100 square feet) of insulation and (2) a "control sample" of R-1.6 (R-ll) unfaced standard glass wool insulation product were prepared.

The samples were each installed in a wall section measuring 121cm (48") x 171cm (67.5") using yellow pine lumber studs spaced 60.96cm (two feet) on centers and having 1.59cm (5/8") fire-rated drywall screwed on the top and bottom thereof. Four thermocouples were located over each sample on top of the drywall. The thus prepared wall was placed in a furnace having five thermocouples located- in it, and was subjected to the time/ temperature conditions of ASTM Standard E119. The results are tabulated below in Table 4:

Table 4

Average Temperature of Average Average Experimental Temperature of Furnace

Time Sample Control Sample Temperature (Minutes) (Degrees C(F) ) (Degrees C(F) ) Degrees C(F) 1 20 (68) 21 (70) 79 (175)

5 21 (69) 22 (71) 763 (1406)

10 37 (99) 38 (100) 702 (1296)

15 51 (123) 52 (125) 747 (1376) 20 59 (138) 59 (138) 795 (1463)

25 60 (140) 60 (140) 812 (1494)

30 65 (149) 70 (158) 835 (1535)

35 75 (167) 79 (174) 856 (1572)

40 82 (179) 87 (188) 872 (1601) 45 86 (187) 89 (192) 879 (1615)

50 88 (191) 92 (197) 892 (1638)

55 89 (193) 94 (202) 898 (1648)

60 93 (199) 101 (214) 907 (1664)

65 101 (214) 109 (229) 928 (1702) 70 107 (224) 114 (238) 934 (1714)

75 111 (232) 119 (246) 937 (1719)

80 115 (239) 128 (263) 943 (1730)

85 119 (247) 190 (374) 949 (1740)

90 127 (261) 283 (542) 953 (1747) 95 155 (311) 386 (726) 957 (1755)

100 217 (422) 512 (953) 965 (1769)

These data indicate that the experimental sample had lower drywall surface temperatures than the control for all times beyond 25 minutes. One criteria of failure used in full-scale ASTM E119 testing is that the average surface temperature not exceed +139"c (+250^βF) over the initial sample temperature. Although small-scale tests tend to overestimate fire endurance, these results indicate that the experimental sample's endurance was approximately 15 minutes longer than the control.

EXAMPLE VII The following 52cm (20.5") x 52cm (20.5") samples were prepared using standard R-1.6 watt/meter-kelvin (R-ll) glass wool insulation product:

Parts by Weight

Each sample was tested in accordance with Underwriters Laboratory (UL) Standard 181 dated August 17, 1981 for factory-made air duct materials and air duct connectors. Section 8, Flame Penetration Test. According to UL Standard 181, material must not burn through before 30 minutes have elapsed from exposure to an open flame. The flame used in this Example VII had temperatures in the range of 1190^βC to 1260°C. The results appear in Table 5 below:

Table 5- UL 181 Test Results

Sample No. Pass/Fail Observations

1 Fail Burn through at 23 mins..

34 sees.

2 Pass No burn through after 30 mins.

3 Fail Burn through at 6 mins. , 26 sees.

4 Pass No burn through after 30 mins.

5 Pass tl

6 Pass It 7 Pass

Sample Nos. 2 and 4-7, treated in accordance with the invention, passed UL Standard 181 thereby qualifying for a Class I rating. EXAMPLE VIII

Aqueous coating solutions having the following compositions were prepared: Composition (Grams)

Each coating composition was stirred and then sprayed onto an 20cm x 20cm (8" x 8") sample of R-2.74 watt/meter-kelvin (R-19) glass wool insulation product and cured for 30 minutes at 177'C (350"F). The samples were then heated with a Bunsen burner playing against the coated surface. In each instance, the samples in the localized area of the flame turned black but did not melt the glass fibers. An untreated R-2.74 (R-19) glass wool insulation product, however, showed melted glass in the localized area of flame impact.

EXAMPLE IX The following aqueous additive compositions were prepared, all components being expressed in grams:

Sample Nos.

The above compositions were applied by spraying onto a surface of standard glass wool insulation product and the thus treated samples were dried at 150°C for 1 hour. The dried samples were subsequently screened by playing a Bunsen burner flame against the treated surface for arbitrary time periods. Those samples did not burn through after being subjected to the flame for a period of time significantly in excess of one minute, were deemed to be suitable phosphate-containing compositions in accordance with this invention since untreated glass wool samples would have burned through in only a few seconds (e.g. less than about 10 seconds). The following observations were made: Sample No. Observations

1 No burn through at more than 9 minutes ¹ 2 Ditto at more than 6 minutes

3 Ditto at 11 minutes

4 Ditto at more than 10 minutes

¹⁵ 5 Ditto at more than 12 minutes The above data demonstrate that all of the tested compositions imparted fire-resistant properties to the glass wool and hence may be used in accordance with this

? ^***■f"l invention.

It will thus be seen that according to the invention an effective treatment of glass fiber and glass fiber articles, to provide fire resistance to the fiber and articles, has been provided. While the invention has been described in

25 connection with what is presently considered to be the most practical and preferred embodiments thereof, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements

30 included within the spirit and scope of the appended claims.

35

Claims

C 1 A I M S 1. A fire-resistant building insulation product comprising glass wool and a phosphate containing compound in close proximity to said glass wool, said phosphate containing compound being present in an amount greater than about 98 grams per square meter (2.0 pounds per 100 square feet) of said glass wool, said phosphate containing compound constituting means for reacting with at least a portion of said glass wool to form a silicate phosphate ceramic in response to said building insulation product being exposed to an elevated temperature sufficient to thermally decompose said dicalcium phosphate, whereby said product is fire-resistant.

2. A product as in claim 1, wherein said phosphate-containing compound is at least one selected from the group consisting of monoammonium phosphate, diammonium phosphate, dicalcium phosphate, monocalcium phosphate, phosphoric acid, aluminum phosphate, and mixtures thereof.

3. A fire-resistant product as in claim 2, wherein said dicalcium phosphate is present in an amount between about 98 and 127 grams per square meter (2.0 and 2.6 pounds per 100 square feet) of said substrate.

4. A product as in claim 2, wherein said layer includes a septum for carrying said phosphate-containing compound, said septum being interposed between layers of said glass wool batting.

5. A fire resistant glass wool insulation product as in claim 4 where said septum is a glass fiber mat, and wherein said phosphate-containing compound is present in an amount to form a silicate phosphate ceramic coating on the glass fibers of said mat.

6. A fire-resistant glass wool batting as in claim 5 wherein said mat is a non-woven glass fiber mat.

7. A fire-resistant glass wool insulation product as in claim 6 wherein said glass wool layers are of substantially equal thicknesses so that said mat is located substantially at the midplane of said insulation product.

8. A glass fiber substrate carrying a phosphate-containing compound which releases phosphoric acid upon thermal degradation, said phosphate-containing compound being present in an amount which provides at least about 14.7 grams (0.3 pounds) of elemental phosphorus per square meter (100 square feet) of said substrate so as to form a silicate phosphate ceramic coating on the glass fibers of said substrate when the substrate is exposed to temperatures which thermally degrade said phosphate-containing compound, whereby said silicate phosphate ceramic coating renders said substrate fire-resistant.

9. A glass fiber substrate as in claim 8 comprised of non-woven glass fibers.

10. A glass fiber substrate as in claim 9 wherein said phosphate-containing compound is at least one selected from the group consisting of monoammonium phosphate, diammonium phosphate, dicalcium phosphate, monocalcium phosphate, phosphoric acid, aluminum phosphate, and mixtures thereof.