IL42018A - Fiberizable boron and fluorine free glass compositions - Google Patents

Description

Fiberiaable boron and fluorine free glass compositions OWENS-CORNING FIEERGLAS CORPORATION C:- 40221 Ε 15269- 5 (combined) SUMMARY OF THE INVENTION The glass compositions of this invention are boron and fluorine free and have the following range of proportions: 4 Components Percent By Weight δ Si02 54 to 64 6 9 to 19 A12°3 7 CaO 9 to 25 8 Ti02 0 to 6 9 MgO 0 to 10 0 ZnO 0 to 6 1 SrO 0 to 6 2 BaO 0 to 6 3 Li20 0 to 4 4 MnO 0 to 2 .5 5 NazO 0 to 2 .5 ό 0 to 2.5 K2° 7 Zr02 0 to 2 8 0 to 1 Fe2°3 9 The glass compositions of this invention may be divided into low 0 alkali glass compositions , wherein the alkali metal oxide concentration is less than 1 one percent by weight , and glass compositions wherein the alkali metal oxide 2 concentration is greater than one percent . The low alkali glasses of this invention 3 may be directly substituted for E glass , which is presently the most common glass 4 composition for textile fibers , as described above . The remaining glass compositions 5 include Li20 as a ^-ux^nS agent and therefore have greater than one percent , 6 by weight , of the alkali metal oxides . 7 The low alkali metal oxide glass compositions may be further divided 8 into four , five and six component glass compositions . The four component glass 9 compositions include Si02 , A^O^ , CaO and 3 to 6% by .' eight Ti02 . The addition O of iO^ , particularly as a substitute for B?0 and F , to the basic three component composition lowers the viscosity of the glass to within the fiberization range , without adversely affecting the liquidus temperature . The liquidus temperatur^ may still be somewhat high for conventional commerical textile fiberization techniques . Further improvements to this composition were therefore desirable .

The five component glass composition includes SiOg , ΑΙ,,Ο^ , CaO , 3 to 5% by weight Ti02 and 1.5 to 4.5% by weight MgO . The addition of MgO and TiOg to the basic three component glass composition reduces the viscosity and liquidus temperature of the glass to within the fiberization ranges and produces a glass composition suitable for fiberization with conventional equipment and techniques .

The six component glass composition includes the basic three component composition described above , including SiC^ , A^O^ anc* CaO , plus 2 to 4% Ti02 , 1.5 to 4% MgO and 1 to 5.5% RO , wherein RO is an oxide selected from the group consisting of ZnO , SrO and BaO , calculated as ZnO . The effect of the addition of ZnO , SrO or BaO is to further lower the liquidus temperature and reduce the req ired concentration of TiOA in the six component glass composition of this invention . The lowering of the concentration of Ti02 is important because Ti02 combines with Fe O , which is added to the batch with the raw materials , to form Δ a yellow or brown color in the resultant fiber which may create a problem in certain applications as described below .

The glass compositions of this invention having an alkali metal oxide concentration greater than one percent includes compositions where lithia (I^O) is the primary fluxing agent and where lithia and titania (TiC^) are substituted in combination for boron and fluorine as the fluxing agents . Where LigO and i02 are added in combination , the preferred composition includes 0. 3 to 2 .5% by weight Li 0 and 2 to 5% TiO_ , where the total weight percent of Li O and TiO„ is 3.5 to 6.5%. This composition may also include 0 to 10% MgO and other ingredients , as described hereinbelow . It has been discovered that L 20 and Ti02 > in combination , have a synergistic effect on the preferred glass compositions . Where is added as the principal fluxing agent , the composition includes 1.5 to 4% Li20 E15269-5 combine and 0 to 10% MgO .

All of the glass compositions described above are boron and fluori^i free and have a viscosity of log 2 .5 poises at a temperature of about 2450° F . or less and a liquidus temperature of about 2200° F . or less . Glass compositions falling within the above range can be drawn into fine , continuous fibers having a diameter of about 15 X 20 ~5 to 55 X 10 ~ 5 inches .

DESCRIPTION OF THE INVENTION As described above , the glass compositions of this invention and the glass fibers made from them fall within the following broad range of ingredients: Ingredient Percent By Weight sio2 54 to 64 9 to 19 A12°3 CaO 9 to 25 Ti02 0 to 6 MgO 0 to 10 ZnO 0 to 6 SrO 0 to 6 BaO 0 to 6 Li20 0 to 4 MnO 0 to 2.5 Na20 0 to 2.5 0 to 2 .5 K2° Zr02 0 to 2 Fe2°3 0 to 1 The four component , low alkali glass composition of this invention consists essentially of, by weight , 54 to 60% Si02 , 9 to 14.5% Al^ , 17 to 24% CaO and 3 to 6% Ti0 . As described above , the preferred composition includes less than one percent , by weight , of the alkali metal oxides , specifically Na20 , K.,0 and Li O , total , calculated as Na O . The method of making a boron and fluorine free textile fiber then includes adding to the basic three component glass having a viscosity of log 2 . 5 poises at 2450° F . or less and a liquidus temperature of about 2200° F . or less and fiberizing the glass . The methods of fiberizing glass are described in the prior art patents , including United States Patent No . 2 , 908 , 036 , assigned to the assignee of the instant application .

The glass composition will also include certain additions or impurities trace amounts up to one percent by weight , including O and and MgO . Specific compositions embodying the preferred composition of the four component , lower alkali glass composition of this invention are described in the following Table 1 , Examples 1 to 9 .

Ingredient Example No. 1 No. 2 No. 3 No 4 No. 5 (% by weight) sio2 58.0 57.3 58.8 5f.'.5 59.5 A12°3 14.1 10.0 13.2 1 .0 13.0 CaO 23.6 25.9 23.9 2:;.7 23.7 i02 3,8 6.0 3.6 3.8 3.8 ftlgO 0.3 0.3 R20 (Na20+K20) 0.1 0.1 Ti2°3 0.2 0.2 Liouidous Temp,°F. 2175°F' 2220°F 2155°F 2185°F 2185°F Viscosity: Temp,°F. at Leg 2.00 2695°F 2540°F 2675°F 2.25 2.50 2495°F 2355°F 2475°F 2.75 3.00 2345°F 2215°F 2325°F Crystal phase Primary Phase anorthite P-wollasto- P-wollasto- anorthit 2 sphene nite nite Secondary Phase sphene sphene sphene sphene P-wollasto nite Ternary Phase tridymite tridymit TABLE 1 E15269-5 (combine ' The five component , low alkali glass composition of this invention consists essentially of , by weight , 54. 5 to 60% Si02 , 9 to 14.5% Al^ , 17 to 24% w CaO , 3 to 5% TiO and 1 .5 to 4% MgO . As described above , the preferred composition also includes less than one percent , by weight , of the alkali metal oxides and the composition will also include certain additions or impurities up to one percent by weight . Specific examples of the five component low alkali glass composition of this invention are given in Table 2 , Examples 1 to 17 .

The fiberizable , six component glass composition and method of this invention eliminates the potential pollutants boron and fluorine and the problems encountered with the four and five glass compositions described above . Further , the color of the fibers formed from the improved six component glass composition compares favorably with E glass , for example , and the physical properties , including the liquidus temperature and viscosity , are within the preferred ranges for fiberi-zation . The six component glass composition of this invention consists essentially of , by weight , 54. 5 to 60% SiO2 , 9 to 14. 5% Al^ , 17 to 24% CaO , 2 to 4% Ti02 > 1.5 to 4% MgO and 1 to 5 .5% RO , wherein RO is an oxide selected from tne group consisting of ZnO , SrO and BaO , calculated as ZnO . The preferred concentrations of SrO and BaO in the six component glass composition are calculated as the equivale of ZnO , in weight percent .

As described above , the preferred composition of the six component glass composition includes less than one percent , by weight , of the alkali metal oxides , specifically Na20 , K20 and I^0 , total , calculated as a20 . The method of making a boron and fluorine free textile glass fiber then includes melting the six component glass composition of this invention to obtain a molten glass having a viscosity of log 2 . 5 poises at 2450° F . , or less , and a liquidus temperature of about 2200° F . , reducing the temperature of the molten glass to within the fiberiza-tion range and drawing a fiber .

Specific examples of the six component glass composition of this invention are described in the following Table 3 , examples I to 24 .

Example No. 1 Ingredient . (% by weight) No. 2 No. 3 No 4 No. 5 No. 6 sio2 58.8 59 57.9 57.9 58.1 58.4 A12°3 10.9 11.9 9.9 12.1 12.1 12.1 CaO 21.5 20.8 22,6 21.4 22.1 21.4 MgO , 3.2 3.3 3.3 3.2 3.2 3.2 Na20 , 0.6 0.6 0.6 • 0.6 0.6 0.9 K2O .,. - - - 0.1 0.1 Ti02 4.9 4.4 4.3 4.7 3.7 3.7 Fe2°3 0.2 0.1 0.1 0.2 0.2 0.2 Liquidus: Temp, °F. 2165 2145 2175 2150 2170 2155 Viscosity: Temp, °F. i at Log Poise 2.0 2635 2615 2585 2600 2600 - 2.5 2402 2425 2380 2400 2410 2405 2.75 2318 2345 . 2303 - 2320 2335 2327 3.0 2240 2275 2237 22J-0 2268 2265 Crystal Phase ** Primary B,G G G G G G Secondary . - B D B A B Ternary D D A - - - Quaternary A ** " sphe trid repr diop TABLE 2 (continued) Example No. 11 Ingredient (% by weight) No. 12 No. 13 No. 14 No. 15 N Si02 59.2 58.4 58.1 59.4 57.9 A1203 12.9 13.7 10.6 ■ 10.5 • 12.1 1 CaO 22.6 20.7 23.6 22.3 22.4 MgO 3.3 3.3 3.2 3.3 2.2 Na20 0.6 0.1 0.6 0.6 0.6 K20 - 0.1 0.1 - 0.1 . Ti02 4.3 3.7 3.7* m 3.7 4.7 Fe20 0.1 0.2 0.1 0.2 0.2 Liquidus: Temp: 2175 2190 2210 2215 2200 Viscosity: Temp: at Log Poise 2.0 2675 2672 2611 2C30 · 2580. 2.5 2465 2470 2380 2415 2405 2.75 2385 2390 2285 2325 2330 3.0 2311 2318 2202 2250 2265 Crystal Phase Primary C A C C B Secondary A B - B A Ternary D — — C * Ingredient (% by weight) No. 2 No. 3 No. 4 N • Si02 57.9 58.9 57.8 57.8 57.3 11.4 11.0 12 12.3 11.7 1 A12°3 CaO 21.8 21.4 21.1 21.6 21.2 2 MgO 2.6 2.6 3.2 2.5 2.7 BaO - - - - 3.8 SrO . 3.4 - - - ZnO - 2.7 1.3 2.6 - Na2b 0.7 1 0.6 %. 1.0 0.8 K2O - 0.05 - - Li20 - - - - Tio2 2.2 2.2 3.7 2.2 2.4 - FE2°3 - , 0.1 0.2 0.1 Liquidus: Temp., °F. 2175 2165 2150 2155 2170* Viscosity: Temp.. °F. at log poises 2.0 2594 2616 2590 2601 2616 2.5 2406 2412 2400 2408 2423 2.75 2328 2333 2320 2330 2345 3.0 2256 2262 2250 2258 2275 Crystal Phase ** Primary G G G G G Secondary - F - C Ternary A Quaternary * ■* " t . . . . . (% by weight) t Si02 57.1 57.7 57.7 58.3 58.2 ,5 11.9 11.4 11.7 11.6 11.6 1 ' A12°3 CaO 18.2 22.9 21.4 21.8 21.7 2 rvigo 3.2 2.8 2.8 2.0 2.0 BaO - - 3.9 - - SrO - - - - • - ZnO 5.2 2.8 - Σ.9 2.9 Na20 0.7 - - • 1.0 1.0 K2O ' ' 0.1 - - - - Li20 - - - -' - Ti02 3.6 2.3 2.4 2.3 2.5 0.2 0.1 0.1 0.1 0.1 Fe2°3 Liquidus: Temp . , °F. 2135 2165 2155 2125 2125 2 Viscosity: Temp., °F. at Log Poise 2.0 2580 2623 2643 2604 2 2.5 - 2389 2433 2445 2410 2 2.75 - 2311 2358 2362 2323 2 3.0 - - 2282 2288 2247 2 Crystal Phase ** Primary G,D G G C,G C Secondary - - - - G Ternary B - • — - - Quaternary - - - - - - ** sp re "F di Example No. 21 Ingredient (% by weight) No. 22 No. 23 Ko . 24 Liquidus : ercp Vis cosit : emt) At 2.0 2586 2590 2625 2.5 2392 241 2403 2360 2.75 2314 2332 2325 2292 3.0 220-9 2266 2251 2242 p-woll "G" re - The glass composition of this invention which substitutes L 20 W and Ti02 , in combination , for boron and fluorine as fluxing agents has the following range of proportions , by weight: Ingredient Percent By Weight Si02 55 to 63 A1203 11 to 18 CaO 9 to 25 Li20 0.3 to 2.5 Ti02 2 to 5 MgO 0 to 10 MnO 0 to 1.5 R2<3 (Na20, K20) 0 to 2.5 BaO 0 to 2.5 SrO 0 to 2.5 Zr02 0 to 2 Fe2°3 0 to 1 The total weight percent of LigO and TiC>2 ranges in the above from 3.5 to 6.5% by weight , in the above .

The preferred composition included within the above ranges are as follows, wherein the glass composition has a viscosity of 2.5 poises at a temperatu of 2450° F. or less and a liquidus temperature of 2200° F. or less: Ingredient Percent By Weight Si0 56.7 to 59 A1203 12.2 to 14.6 CaO 16 to 23 Li20 0.4 to 2.5 TiO0 0.4 to 2.5 MgO 2 to 3.5 R20 ( a20, K20;> 0 to 0.8 BaO 0 to 2.5 E 15269-5 (combined) Ingredient Percent By Weight -~ Zr02 0 to 2 ^ Fe2°3 0 to 1 The total weight percent of LigO and Ti02 in the above ranges from 3.5 to 6. 5%.

Specific compositions included within the above ranges are described in the following Table 4 , Examples 1 to 16 .

. . . . Si02 59.6 57.9 56.7 56.7 56.9 57 14 14.1 14 14.1 14.1 14 A12°3 CaO 17.7 19.2 19.3 19.6 20 23 Li20 1.2 1.2 1.2 1.2 1.2 0.

Ti02 3.7 3.7 3.7 4.3 3.7 3.

MgO 2.8 3 3 3.1 3.2 — Na20 0.7 0.7 0.7 0.7 0.7 0.

K2O 0.1 0.1 0.1 0.1 0.1 0.

MnO — — 1.2 — — — BaO — — — — Zr02 — — — — — ■ — 0.3 0.3 0.2 0.2 0.2 0.

Fe2°3 Liquidus: Tem . , °F . 2095 2100 2125 2115 2110 ' 215 Viscosity: Temp.,°F. at Log Poise 2.0 2675 2600 — 254G 2572 265 2.5 2440 2385 — 2335 2365 244 2.75 2353 2297 — 2240 2280 236 3.0 — 2220 — — 2210 229 Crystal Phases* Primary A A B F F A Secondary B B - C - B Ternary D D - - - E *"A" represe "C" represen "E" represent Si02 57.5 57 59 62.3 57 57. 14.1 14.6 14.1 11.7 A12°3 14.1 14 CaO 22.5 22.5 21 19.6 20 18.

Li20 1.5 0.5 1.5 2.4 1.5 1.

Ti02 3.7 3.7 3.7 2.8 3.7 3.

MgO — — . — 3.2 2.

Na20 0.1 0.1 0.1 0.2 0.1 0.

K90 0.1 0.1 0.1 0.1 0.2 0.

MnO BaO 1. ZrO 0.2 0.3 0.3 0.3 Fe2°3 0.3 0. Liquidus: Temp.,°F. 2135 2145 2140 2200 2135 Vicosity: Temp.,°F. at Log Poise 2.0 2550 2575 2640 2625 2520 256 2.5 2350 2365 2415 2392 2323 2365 2.75 2283 2283 2330 2297 2245 — 3.0 2195 2210 2245 2216 2187 221 Crystal Phases* Primary B A B E F F Secondary E E - - A Ternary — ■ B - - - B "C" represent "E" represent E15269-5 (combined) The glass compositions of this invention and the glass fibers made from them which utilize lithia (Li^O) as the primary fluxing agent fall within the following range of proportions: Ingredient Percent By Weight sio2 56 to 64 12 to 19 A12°3 CaO 9 to 25 MgO 0 to 10 Li20 1.5 to 4 Na20, K20 0 to 2.5 0 to 1 Fe2°3 and wherein the sum of Si02 and A^O^ is preferably 72 to 79% by weight and the sum of CaO and MgO is 17 to 26% by weight: Specific glass compositions included within the above range are described in the following Table 5 , Examples 1 to 16.

E15269-5 (combined) The viscosity determinations in the Examples above were obtained ^ using the apparatus and procedures described in United States Patent No . 3 , 056 , 283 and in the article in The Journal of the American Ceramic Society , Vol . 42 , No . 11 , November , 1959 , pages 537-541 . The article is entitled "Improved Apparatus for Rapid Measurement of Viscosity of Glass at High Temperatures" by Ralph L . Tiede . Other specific viscosity determinations referred to herein also would be measured by the apparatus and procedures in the Tiede article .

The glass compositions of this invention , some of which are described in the above Tables , preferably have a liquidus temperature of 2200° F . , or 2 50 less and a viscosity of log poise 2 . 50 (i . e . 10 ' poises) at 2450° F . , or less .

The glasses having less than one percent by weight alkali metal oxides are therefore suitable for fiber forming and direct replacement of E glass and similar textile glass fiber forming glasses containing boron and fluorine with boron and fluorine free glasses is therefore possible .

All of the glass compositions in Tables 1 to 3 contain one percent by weight or less of the alkali metal oxides , as described above , and thus these glasses in fiber form will be acceptable to consumers requiring low levels of the alkali metal oxides , such as E glass . The primary glass forming ingredients in the glass compositions of this invention are SiO„ and Al 0„ . The basic three oxides of the glass compositions are ancl CaO .

Titania (TiOg) is used in the glass compositions of this invention as a flux in place of boron and fluorine . TiOg is marketed as a fine white powder , finding extensive use in paints to give opacity to enamels and the like . It is also used in glass decoration , however the use of TiO^ as a substitute for an<^ F^ to lower the viscosity of fiberizable glasses , without adversely affecting the liquidus temperature , was quite unexpected . iO^ should be used in these compositions in amounts of 6% by weight , or less , preferably less than 3 . 5% .

Concentrations of titania above G% causes the liquidus temperature to reach undesirable levels . Further , concentrations of iO^ above 4% can cause a brownish or yellowish coloration to the glass fibers . This can be a problem where the fibers E15269-5 (combined) The concentration of MgO in the five and six component glass --composition is preferably less than 4%, by weight . Concentrations of MgO above 4% increases the liquidus temperature above the preferred limit for fiberization . MgO may be added to the glass composition by the raw materials and has been known to have an affect upon the melting temperature of E glass , for example , and is added to E glass to control the devitrification of diopsides (CaOMg02Si02) . It has now been discovered that 1.5 to 4.5% by weight of MgO reduces and controls the liquidus temperature to within the fiberization range , and as described above , and reduces the iOg required in the composition , which improves the color of the fibers . It will be noted from the examples in Tables 2 and 3 that MgO is substituted primarily for CaO .

The glass compositions disclosed in Table 3 includes ZnO , SrO or BaO , which is substituted for some of the iOg used in the six component glass composition . This improves or eliminates the discoloration of the fibers and the addition of these oxides further lower the liquidus temperature and viscosity . The six component glass composition of this invention then provides a full substitute for E glass , without the potential pollutants boron and fluorine . The affect of ZnO , SrO and BaO to lower the liquidus temperature and reduce the required concentratio of Ti02 in the six component glass composition of this invention was not expected from the teaching of the prior art and is considered to be an important advancement in the production of fiberizable boron and fluorine free glass compositions .

Lithia (LigO ) and titania (TiO ^) are used in combination in the glass compositions given in Table 4 as fluxes in place of boron and fluorine .

The synergistic effect of the combination of LigO and TiO^ to lower the viscosity of the glass composition , without adversely affecting the liqui dus , is an important step in producing fiberi zable glass compositions which are free of the potential pollutants , boron and fluorine . MgO may also be added to this glass composition to lower the liq uidus temperature , i f required , to withi n the fiberization rang e .

Lithia is the only one of the three commonly used alkali metal oxides (LigO , 0 and Na.,0 ) t hai: can be used in mount up to 4% by weig ht E15269-5 (combined) Concentrations of lithia above 2.5% by weight, in combination with TiOg, may cause a raising of the liquidus temperature to undesired levels . Titania should 3 be used in these glass compositions in amounts of 5% by weight or less. When used 4 in amounts over 5%, the liquidus temperature may raise above the preferred limit 5 for fiberization . 6 The alkali metal oxides , agO and K^O , can be used individually 7 or collectively to control viscosity . In either case , the total of Na20 and K^O 8 should not exceed about 2.5%, by weight where the total alkali metal oxide can 9 exceed one percent and preferably not be more than one percent by weight. 10 Amounts of Na,,0 and K^O over 2.5% by weight causes an undesirable raising 11 of the liquidus temperature, which outweighs the advantages these oxides have 12 in keeping viscosity within the desired range. 13 In Examples 1 to 5 , 8, 9 and 16 of Table 4, ^&< was added as 14 a batch material. In the other Examples of Table 4, a^O was not added intentionally 15 but entered the glass compositions as an impurity in one of the batch materials . KgO 16 entered all of the examples in Table 4 as a batch material impurity. Glass com¬ 17 positions with no K_0 or Na O would also fall within the scope of this invention. 2 18 Certain oxides of the group BaO , CaO , MgO and MnO are beneficial 19 additives to the glass composition of Table 4. SrO should be equally beneficial. Thi 20 group of oxides is useful to control liquidus without adversely affecting viscosity. 21 The best results have been found where the oxides are used collectively in amounts 22 of 27% by weight and the best results are generally obtained when MgO and CaO 23 are used, individually or in combination. MnO is preferably used in amounts of 24 0.5% or less. When MnO is used in amounts over 0.5%, it can cause a brownish 25 or purple color in the glass composition and fibers . 26 In the examples given in Table 5 , Li90 is used as a flux in place 27 of the removed boron and fluorine. Lithia controls the viscosity in these composition £8 while maintaining' a tolerable liquidus. Each glass composition i ihis invention 29 I should contain at least 1.5% Li^O. Lithia is the only one of the three commonly n I us d alkali metal oxides (Li.^O. K O and a^O) that can be used in amounts up E15269-5 (combined) ' In examples 1 , 8 , 9 and 13 of Table 5 , Na O was added as a batch* mat erial . In the other Examples of Table 5 , Na 0 was not added intentionally but entere glass composition as an impurity in one of the batch raw materials . I^O was added as a batch material in example 14 of Table 5. KgO entered all of the other examples in Table 5 as a batch material impurity .

As described above , CaO and MgO are beneficial additives to the compositions given in Table 5 . BaO , MnO and ZnO are also beneficial , however , to maintain the desired liquidus-viscosity relationships described above , the total or sum of CaO and MgO should be 17 to 26%, by weight .

Fe^O^ can enter all of the glass compositions of this invention as an impurity of the batch raw materials or it may be added intentionally up to amounts of one percent by weight . Fe„0 can , however , discolor the glass and fibers drawn from the glass as described above and therefore should be kept as low as possible when clear glass fibers are required for some end use especially where 1O2 is included . Various other impurities or tramp materials may also be present in the glass compositions in amounts of about 0.3% or less by weight , without adversely affecting the glasses or fibers . These impurities will include chromic oxide (CT Og) , oxides qf vanadium and phosphates . These materials can enter the glass as raw material impurities or can be products formed by the chemical reaction of the molten glass with the furnace components . Oxides of sulphur can also be present in trace amounts , either from batch impurities or from deliberate additions of sulfates as fining agents .

Modifications and variations within the scope of the appended claims are intended to be included . 42018/3 - 16 -

Claims (1)

1. CLAIMS A boron and fluorine free glass having a liquldus temperature of about or and having a viscosity of log poises at or consisting essentially by Component Percent by Weight 12 1973 sio2 5 to 64 one of the following 9 to 19 conditions is CaO 9 25 less than 0 6 SrO than 0 10 MnO more than present ZnO 6 SrO 0 6 BaO 0 to 6 Li20 0 to 4 MnO 0 0 K2O 0 to 2 0 to 2 Fe203 0 to 1 provided that it contains at least Ti02 or A glass composition according to Claim consisting essentially by Component Percent Weight to 60 9 to 2 1973 17 to 24 for Si0 less than 2 to 4 to 4 1 to 0 to 1 0 1 0 to 0 to 1 RO SrO or and the concentration of RO is calculated as A glass according Claim consisting essentially by weight of Component Percent by Weight 12 55 if Zr02 present 1Q CaO 9 to 25 to 2 to 5 0 to 10 mo o to 0 to BaO 0 to SrO 0 to wherein the total weight percent of and Ti02 is to A glass composition according to Claim consisting essentially by weight of Component Percent by Weight Si02 56 to 64 12 to CaO 9 to 0 to 10 0 to A glass composition according to Claim having 3 to by weight A glass composition according to Claim 1 or having 3 to by weight and to by weight A glass composition according to Claim having 2 to by weight to and 1 to by weight wherein is SrO or A glass composition according to Claim having to 4 A glass composition according to Claim wherein the total of and is 72 to by A glass composition according to Claim consisting essentially of by to 60 percent 9 to percent 17 to 24 percent CaO and 3 to 6 percent A glass composition according to Claims 1 or consisting essentially by to 60 percent 9 to percent 17 to 24 percent 3 to 5 percent and to percent A glass composition according to Claim comprising by weight of to 60 percent 9 to percent 17 to 24 percent 2 to 4 percent to 4 percent MgO and 1 to 6 percent wherein fi is Sr or and the amount of is calculated as A glass composition according to an one of Claims 1 to characterized in that said glass composition includes less tha one by of and calculated as A glass composition according to Claim 1 or wherein the total weight percent of and is than one percent and the total weight percent of and is less than composition according to any one of the preceding having a concentration of MgO between about and by A glass composition according to Claim wherein the total of and is 72 to by weight and the total of CaO and MgO is 17 to by A glass composition according to any one of the preceding having a liquidus temperature of about or and having a viscosity of log poises at or The method of making a boron and fluorine free textile glass according to any one of the preceding comprising the steps of melting the 12 glass batch consisting essentially b 1973 for SiOp less to 60 percent 9 to percent 17 to 24 than percent 2 to 4 percent to 4 MgO and the equivalent of 1 to 6 percent of the oxide wherein RO is SrO or calculated as reducing the temperature of the molten glass to within the fiberization range and drawing a glass e method of making a glass fiber accordin to Claim wherein the glass batch has a liquidus temperature of or less and a viscosity of log poises at or including melting the glass batch by heating the batch to a temperature of about and above the melting temperature of the and lowering the temperature of the molten glass to a temperature of from about to insufficientOCRQuality