HK1097405B - High temperature resistant vitreous inorganic fiber - Google Patents

Description

High temperature resistant vitreous inorganic fiber

Background

High temperature resistant vitreous fibres for use as thermal or acoustic insulation materials are provided having a use temperature of at least up to 1000 ℃. The high temperature resistant fibers can be easily manufactured, exhibit low shrinkage, maintain good mechanical strength after exposure to operating temperatures, and are not durable in physiological fluids.

The insulation industry has identified a need for fibers that are not durable in physiological fluids, such as lung fluid, in thermal and acoustical insulation applications. While alternative materials have been proposed, the use temperature limits of these materials have not been high enough to be suitable for many applications where high temperature resistant fibers are used, including refractory glass and ceramic fibers. In particular, in order to provide effective thermal protection to the article being insulated, the high temperature resistant fibers should exhibit minimal linear shrinkage at the expected exposure temperatures.

Various compositions have been proposed which belong to the man-made vitreous fibre material system, which are decomposable in a physiological medium. These glass fibers generally have a large alkali metal oxide content, which often results in a low service temperature limit.

Canadian patent application No.2017344 describes a glass fiber having physiological solubility, consisting of silica, calcium oxide and Na as essential components₂O, preferred component oxidationMagnesium and K₂O and optional components boron oxide, alumina, titanium dioxide, iron oxides, and fluorides.

International publication No. WO90/02713 describes mineral fibers soluble in saline solution, the fibers having a composition comprising silica, alumina, iron oxide, calcium oxide, magnesium oxide, Na₂O and K₂Composition of O.

U.S. Pat. No.5108957 describes a glass composition for forming fibers that are degradable in physiological media comprising the essential components silica, calcium oxide, Na₂O plus K₂O and boron oxide, and optionally alumina, magnesia, fluoride and P₂O₅. It describes the effect of the presence of phosphorus on increasing the rate of decomposition of the fiber in a physiological medium.

Other patents cited the effect of phosphorus to contribute to the biological solubility of mineral fibers include International publication No. WO92/09536, which describes a mineral fiber containing primarily silica and calcium oxide but optionally magnesium oxide and Na₂O plus K₂O, wherein the presence of phosphorus oxides reduces the stabilizing effect of aluminum and iron on the glass matrix. These fibers are typically produced at lower temperatures than refractory ceramic fibers. Applicants have found that phosphorus oxides in amounts as low as a few percent can cause severe damage and/or corrosion of furnace components at the required melting temperatures (1700-.

Canadian patent application No.2043699 describes fibers which decompose in the presence of physiological media and which comprise silica, alumina, calcium oxide, magnesium oxide, P₂O₅Optionally iron oxide and Na₂O plus K₂O。

French patent application No.2662687 describes mineral fibres which decompose in the presence of physiological media and which comprise silica, alumina, calcium oxide, magnesium oxide, P₂O₅Iron oxide and Na₂O plus K₂O plus TiO₂。

U.S. patent No.4604097 describes bioabsorbable glass fibers, typically comprising a binary mixture of calcium oxide and phosphorus pentoxide, but with other components such as calcium fluoride, water and one or more oxides such as magnesium oxide, zinc oxide, strontium oxide, sodium oxide, potassium oxide, lithium oxide or aluminum oxide.

International publication No. wo92/07801 describes bioabsorbable glass fibers comprising phosphorus pentoxide and iron oxide. P₂O₅May be replaced by silica and a portion of the iron oxide may be replaced by alumina. Optionally, the fibers comprise a divalent cationic compound selected from Ca, Zn and/or Mg, and an alkali metal cationic compound selected from Na, K and/or Li.

Us patent 5055428 describes a soda lime aluminoborosilicate glass fiber composition that is soluble in synthetic lung fluids. The content of alumina increases with boron oxide and silica, calcia, magnesia, K₂O and optionally Na₂The adjustment of O decreases. Other components may include iron oxides, titanium dioxide, fluorine, barium oxide, and zinc oxide.

International publication No. wo87/05007 describes inorganic fibers having solubility in brine solutions and comprising silica, calcium oxide, magnesium oxide, and optionally alumina. International publication No. wo89/12032 describes inorganic fibers having extractable silicon in physiological saline solution, including silica, calcium oxide, optionally magnesium oxide, alkali metal oxides, and one or more of alumina, zirconia, titania, boria, and iron oxides.

International publication No. wo93/15028 describes brine-soluble vitreous fibres which, in one use, crystallize to diopside upon exposure to 1000 ℃ and/or 800 ℃ for 24 hours and have a composition in weight percent: silica 59-64, alumina 0-3.5, calcium oxide 19-23 and magnesium oxide 14-17, which, in another use, crystallize as wollastonite and/or pseudo-wollastonite and have a composition in weight percent: 60-67 parts of silicon dioxide, 0-3.5 parts of aluminum oxide, 26-35 parts of calcium oxide and 4-6 parts of magnesium oxide.

International publication No. WO03/059835 discloses that La is contained in an amount of 1.3 to 1.5 wt%₂O₃Calcium-silicate fibers of (1).

However, the fibers described in the above identified patent publications are limited in their temperature of use and are therefore not suitable for high temperature insulation applications, such as for furnace linings above 1000 ℃, and reinforcement applications such as metal matrix composites and friction applications.

U.S. patents 6030910, 6025288, and 5874375, assigned to Unifrax Corporation, discloses specific inorganic fibers comprising products that are essentially fiberizable melts of silica and magnesia that are soluble in physiological fluids and have good shrinkage and mechanical properties at high use temperature extremes.

Products based on a non-durable fiber chemistry are sold under the trademark INSULFRAX by Unifrax Corporation (NiagaraFalls, New York) and have 65% SiO₂、31.1％CaO、3.2％MgO、0.3％Al₂O₃And 0.3% Fe₂O₃Nominal weight percent of (c). Another product is sold under the trademark SUPERWOOL by Thermal Ceramics (located in Augusta, Georgia) and consists of 58.5% SiO by weight₂35.4% CaO, 4.1% MgO and 0.7% Al₂O₃And (4) forming. This material has a use limit of 1000 c and melts at about 1280 c, which is too low for the above-mentioned requirements for high temperature insulation purposes.

International application No. WO94/15883 discloses a method for producing Al with an additional component₂O₃、ZrO₂And TiO₂CaO/MgO/SiO of₂Fiber, and its saline solubility and melt resistance were investigated. The document states that the brine solubility appears to increase with increasing amounts of MgO, while ZrO₂And Al₂O₃Is disadvantageous in solubility. TiO 2₂(0.71-0.74 mol%) and Al₂O₃The presence of (0.51-0.55 mol%) results in fibers that do not meet the shrinkage criterion of 3.5% or less at 1260 ℃. The document also states that SiO₂Too high a fibre is difficult or impossible to form and has been cited with 70.04, 73.28 and 78.07% SiO₂As an example of a sample that cannot be fiberized.

U.S. patents 5332699, 5421714, 5994247 and 6180546 relate to high temperature resistant soluble inorganic fibers.

In addition to temperature resistance, expressed in terms of shrinkage characteristics, which is important in fibers used for thermal insulation, it is also desirable that the fibers have mechanical strength characteristics during or after exposure to service or operating temperatures, which can allow the fibers to maintain structural integrity and thermal insulation characteristics in use.

One characteristic of the mechanical integrity of a fiber is its after-use brittleness. The more brittle a fiber is, i.e. the more easily it can be comminuted or broken into a powder, the less mechanical integrity it has. It has been found that, in general, refractory fibers that exhibit both high temperature resistance and non-durability in physiological fluids also exhibit a high degree of post-use brittleness. This results in the fiber lacking the strength or mechanical integrity to provide the necessary structure to accomplish its insulating purpose after exposure to the operating temperature.

Applicants have discovered high temperature resistant, non-durable fibers that do exhibit good mechanical integrity up to the operating temperature. Other measures of mechanical integrity of fibers include compressive strength and compression recovery.

However, a refractory glass composition that may exhibit the targeted durability, shrinkage at temperature, and strength characteristics may not be easily fiberized by spinning or blowing from a melt of its components.

There is therefore a need to provide high temperature resistant refractory glass fibers that can be easily manufactured from a melt having a viscosity suitable for blowing or spinning the fibers and that are not durable in physiological fluids.

There is also a need to provide high temperature resistant refractory glass fibers that are not durable in physiological fluids and exhibit good mechanical strength up to the operating temperature.

It is further desirable to provide high temperature resistant, fire resistant glass fibers that are not durable in physiological fluids and exhibit low shrinkage at use temperatures.

Summary of The Invention

Provided is a high-temperature-resistant and fire-resistant vitreous inorganic fiber which is not durable in physiological fluids. The fibers are more soluble in simulated lung fluid than standard aluminosilicate refractory ceramic fibers and exhibit temperature use limits up to at least 1000 ℃ or higher. These fibers retain mechanical strength after exposure to service temperatures. Fibers have been identified that meet the requirements of being fiberizable, resistant to high temperatures, and non-durable in physiological fluids, wherein the fiber composition comprises Silica (SiO)₂) Magnesium oxide (MgO), and at least one compound containing lanthanum or a lanthanide element.

In some embodiments, fibers are made from a melt of ingredients comprising silica, magnesia, and a lanthanide-containing compound in amounts in the range of 71.25 wt.% to about 86 wt.%.

A low shrinkage, fire resistant, vitreous inorganic fiber based on a magnesium-silicate system at use temperatures up to at least 1000 ℃ is provided that maintains mechanical integrity after exposure to use temperatures and is not durable in physiological fluids such as lung fluid.

According to one embodiment, the non-durable refractory vitreous inorganic fiber includes the fiberization product of about 71.25 to about 86 weight percent silica, about 14 to about 28.75 weight percent magnesia, and about greater than 0 to about 6 weight percent of a lanthanide series element-containing compound. The lanthanide-containing compound can be, for example, an oxide of a lanthanide.

According to one embodiment, the non-durable refractory vitreous inorganic fiber comprises the fiberization product of about 71.25 to about 86 weight percent silica, about 14 to about 28.75 weight percent magnesia, and about greater than 0 to about 6 weight percent of a lanthanide series element-containing compound, such as an oxide, and optionally zirconia. If zirconia is included in the fiberizing melt, it is generally included in an amount in the range of from greater than 0 to about 11 weight percent.

According to another embodiment, the non-durable refractory vitreous inorganic fiber includes about 71.25 wt% to about 86 wt% silica, about 14 wt% to about 28.75 wt% magnesia, and about greater than 0 to about 6 wt% of a lanthanide series element-containing compound and less than about 1 wt% as Fe₂O₃Fiberization product of iron oxide impurities. The lanthanide-containing compound can be, for example, an oxide of a lanthanide.

According to some embodiments, the high temperature resistant, non-durable fibers preferably comprise a minimum of about 2 wt% alumina (Al)₂O₃)。

A method is provided for producing high temperature resistant vitreous inorganic fibers, wherein the fibers have a use temperature up to at least 1000 ℃, maintain mechanical integrity up to a service temperature, and are not durable in physiological fluids, comprising:

forming a melt with ingredients comprising about 71.25 wt% to about 86 wt% silica, about 14 wt% to about 28.75 wt% magnesia, and about greater than 0 to about 6 wt% of a lanthanum or lanthanide series element containing compound, and producing fibers from the melt.

Also provided is a method of producing high temperature resistant vitreous inorganic fibers, wherein the fibers have a use temperature up to at least 1000 ℃, and maintain mechanical integrity up to a service temperature and are not durable in physiological fluids, comprising:

forming a melt with ingredients comprising about 71.25 wt% to about 86 wt% silica, about 14 wt% to about 28.75 wt% magnesia, and about greater than 0 to about 6 wt% of a lanthanum or lanthanide series containing compound, and optionally zirconia; and producing fibers from the melt.

The melt composition used to produce the fibers of the present invention provides a melt viscosity suitable for blowing or spinning the fibers and provides mechanical strength for exposure to service temperatures.

Also provided is a method of insulating an article comprising disposing on, in, near or around the article a thermal insulation material having a working temperature up to at least 1000 ℃ or more and maintaining mechanical integrity up to a use temperature and being non-durable in physiological fluids, the thermal insulation material comprising the fiberization product of a fiber melt comprising silica, magnesia, a lanthanum-or lanthanide-containing compound, and optionally zirconia.

Brief Description of Drawings

FIG. 1A is a viscosity versus temperature curve of the melt chemistry of a commercially available spun aluminosilicate fiber.

Figure 1B is a viscosity versus temperature curve of the melt chemistry of a commercially available blown aluminosilicate fiber.

Detailed Description

A high temperature resistant fiber for use as a thermal, electrical, and acoustical insulation material is provided which has a temperature use limit of greater than 1000 ℃ and is not durable in physiological fluids such as lung fluid. By non-durable in physiological fluids is meant that the fibers are at least partially dissolved in such fluids (e.g., simulated lung fluid) in an in vitro test.

In order for a glass composition to be a viable alternative for producing a satisfactory high temperature refractory fiber product, the fibers to be produced must be manufacturable, sufficiently soluble in physiological fluids, and capable of withstanding high temperatures with minimal shrinkage and minimal loss of mechanical integrity during exposure to high operating temperatures.

"viscosity" refers to the ability of a glass melt to resist flow or shear stress. The viscosity-temperature relationship is critical in determining whether a given glass composition can be fiberized. The optimum viscosity curve will have a low viscosity (5-50 poise) at the fiberizing temperature and will gradually increase as the temperature decreases. If the melt is not sufficiently viscous (i.e., too thin) at the fiberizing temperature, short fine fibers are obtained with a high proportion of fiberized material (shot). If the melt is too viscous at the fiberizing temperature, the resulting fiber will be extremely thick (large diameter) and short.

The viscosity depends on the melt chemical composition, which is also influenced by the element or compound used as viscosity modifier. The applicants have found that the use of a lanthanide element-containing compound as a viscosity modifier for such fiber chemistry systems enables the fibers to be blown or spun from the fiber melt. However, it is desirable that such viscosity modifiers, whether type or amount, do not adversely affect the solubility, shrink resistance or mechanical strength of the blown or spun fibers in accordance with the present invention.

Mechanical integrity is also an important property, as the fiber must support its own weight in any application and must also be able to withstand abrasion caused by moving air or gas. An indication of fiber integrity and mechanical strength is provided by visual and tactile observation and mechanical measurement of these properties of the fiber after exposure to service temperatures.

The fibers have compressive strength within a targeted range and also have high compression recovery or resilience as compared to standard commercial aluminosilicate fibers.

The fibers of the present invention are significantly less durable in simulated lung fluid than conventional refractory ceramic fibers such as aluminosilicates (about 50/50 wt%) and alumino-zirconia-silicates or AZS (about 30/16/54 wt%).

Refractory vitreous fibres that are not durable are made by standard glass and ceramic fibre manufacturing methods. The feedstock, e.g., silica, any suitable magnesia source, e.g., enstatite, forsterite, magnesia, magnesite, calcined magnesite, magnesium zirconate, periclase, steatite, or talc, and if zirconia is included in the fiber melt, any suitable zirconia source, e.g., baddeleyite, magnesium zirconate, zircon, or zirconia, are delivered in selected proportions from a silo to a furnace where they are melted and blown using fiberizing nozzles, or spun, in either a batch or continuous mode.

The viscosity of the melt can optionally be controlled by the presence of a viscosity modifier sufficient to provide fiberization required by the desired application. The viscosity modifier may be present in the raw materials supplying the main components of the melt or may be added separately, at least in part. The desired particle size of the feedstock is determined by the firing conditions, including furnace Size (SEF), pour rate, melting temperature, residence time, and the like.

The lanthanide element-containing compound can be effectively utilized to increase the viscosity of a fiber melt containing silica and magnesia as main components, thereby increasing the fiberizability of the fiber melt. The use of the lanthanide element-containing compound increases viscosity and selects fiberization without adversely affecting thermal, mechanical, or solubility of the fiber product.

According to one embodiment, the refractory vitreous inorganic fibers are capable of withstanding service temperatures up to at least 1000 ℃, have a linear shrinkage of less than about 6%, preferably less than about 5%, exhibit mechanical integrity at service temperatures, and are not durable in physiological fluids such as pulmonary fluids. The non-durable refractory vitreous inorganic fibers comprise the fiberization product of about 71.25 to about 86 weight percent silica, about 14 to about 28.75 weight percent magnesia, and about greater than 0 to about 6 weight percent of a lanthanum or lanthanide series containing compound. The fiberizing melt from which the fiber product is made may also include 0 to about 11 weight percent zirconia.

The fibers should contain no more than about 1 wt% calcium oxide impurities. According to other embodiments, the fibers should not contain more than about 1 wt% iron oxide impurities (as Fe)₂O₃Meter). Other elements or compounds that can be used as viscosity modifiers that, when added to the melt, affect the melt viscosity to approximate the profile or shape of the viscosity/temperature curve of the melt, which is susceptible to fiberization, as described below.

Useful lanthanides include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and mixtures thereof. The element Y is similar to many of the lanthanides and is found with them in nature. For the purposes of this specification, the element Y is considered to be included in the lanthanide series. In some embodiments, a compound containing the lanthanide elements La, Ce, Pr, Nd, or combinations thereof, may be added to the fiber melt. A particularly useful lanthanide that can be added to the fiber melt is La.

The lanthanide-containing compound can include, but is not limited to, lanthanide-containing bromides, lanthanide-containing chlorides, lanthanide-containing fluorides, lanthanide-containing phosphates, lanthanide-containing nitrates, lanthanide-containing nitrites, lanthanide-containing oxides, and lanthanide-containing sulfates.

Oxides of the lanthanide series elements are useful for increasing the viscosity of a fiber melt comprising silica and magnesia to enhance the fiberizability of the melt. A particularly useful oxide of the lanthanide series element is La₂O₃。La₂O₃Often referred to in the chemical arts as "lanthanum" or "lanthanum oxide," and thus, these terms are used interchangeably in the specification.

As noted above, mixtures of lanthanide-containing compounds can be used in the fiber melt to increase melt viscosity. Chemically, lanthanides are very similar and are often found together in mineral deposits. The term "misch metal" is used to designate a naturally occurring mixture of lanthanides. Further refining is required to separate and convert the misch metal oxide into its constituent misch metal oxides. Thus, the misch metal oxide itself can be used as the lanthanide-containing compound in the fiber melt.

Although alumina is a viscosity modifier, inclusion of alumina in the fiber melt chemistry results in a decrease in solubility of the resulting fiber in physiological saline solution. Thus, it is desirable to limit the amount of alumina present in the fiber melt chemistry to at least less than about 2 weight percent, and as such, to less than about 1 weight percent for the raw materials used.

One way to test whether fibers of a specified composition can be readily manufactured at an acceptable quality level is to determine whether the viscosity curve of the tested chemical composition matches that of a known product that can be readily fiberized. The addition of lanthanum oxide to the magnesium-silicate melt enhances fiberization by extending the viscosity curve of the melt to lower temperatures and high viscosities. Because the lanthanum-silicate system is a more refractory system than the magnesium-silicate system, the thermal properties of the resulting fiber are also enhanced.

The shape of the viscosity versus temperature curve of the glass composition represents the ease of melt fiberization and thus the quality of the resulting fiber (affecting, for example, fiber particle content, fiber diameter, and fiber length). Glasses generally have a low viscosity at high temperatures. As the temperature decreases, the viscosity increases. The viscosity value at a given temperature will vary as a function of composition, as will the overall steepness of the viscosity versus temperature curve. The viscosity curve of a melt of silica, magnesia, and a lanthanum-containing or other lanthanide series element compound has a viscosity that approximates the target viscosity curve of fig. 1A for a commercially available spun aluminosilicate fiber.

The fiber comprises the fiberization product of about 65 to 86 weight percent silica, about 14 to about 35 weight percent magnesia, and a lanthanide series element-containing compound.

According to some embodiments, the non-durable refractory vitreous inorganic fiber comprises the fiberization product of about 71.25 to about 86 weight percent silica, about 14 to about 28.75 weight percent magnesia, and about greater than 0 to about 6 weight percent of a lanthanum or lanthanide series containing compound.

According to other embodiments, the non-durable, high temperature resistant vitreous inorganic fiber comprises the fiberization product of about 71.25 to about 86 weight percent silica, about 14 to about 28.75 weight percent magnesia, and about greater than 0 to about 6 weight percent of a lanthanum or lanthanide series containing compound, 0 to about 11 weight percent zirconia, and less than about 2 weight percent alumina.

In the above-described melts and fibers, the feasible silica levels are between about 71.25 wt.% and about 86 wt.%, preferably between about 72 wt.% and about 80 wt.%, with the upper limit of silica being limited only by the fiber manufacturing capabilities.

According to another embodiment, the non-durable, high temperature resistant vitreous inorganic fiber includes the fiberization product of about 72 to about 80 weight percent silica, about 21 to about 28 weight percent magnesia, and greater than 0 to about 6 weight percent of a lanthanide series element-containing compound. Of course, the sum of the amounts of silica, magnesia and the lanthanide element-containing compound cannot exceed 100 wt% by weight.

According to yet another embodiment, the non-durable refractory vitreous inorganic fiber comprises the fiberization product of about 71.25 to about 86 weight percent silica, about 14 to about 28.75 weight percent magnesia, and about greater than 0 to about 6 weight percent of a lanthanide series element-containing compound, wherein the fiber contains substantially no alkali metal oxide.

The fibers contain substantially no alkali metal above trace impurities. The term "trace impurities" refers to those amounts of material in the fiberization product that are not intentionally added to the fiber melt, but may be present in the raw material from which the fibers are produced. Thus, the term "substantially free of alkali metal oxide" means that the alkali metal oxide, if present in the fiber, is from the source material and that the alkali metal oxide is not intentionally added to the fiber melt. Typically, the fibers may contain alkali metal oxides from the starting materials in amounts up to about a fraction of a percent. Thus, the alkali metal content of these fibers is typically in the range of trace impurities, or at most a few tenths of a percent, based on the alkali metal oxide. Other impurities may include amounts of Fe₂0₃Less than about 1 wt% or as low as possible iron oxide.

The above-described non-durable low shrinkage vitreous inorganic fibers are advantageous compared to conventional kaolin, AZS and aluminosilicate durable refractory ceramic fibers in terms of mechanical strength up to service temperature.

Fibers are made from a melt of ingredients comprising silica, magnesia, a lanthanide series element-containing compound, and optionally zirconia by known fiber spinning or blowing processes. The fibers may have a fiber diameter that is only a practical upper limit, as fiber diameter is the ability to spin or blow a product having the desired diameter.

The fibers can be manufactured using existing fiberization techniques and formed into a variety of product forms including, but not limited to, bulk fibers, fibrous blankets, papers, felts, vacuum cast shapes, and composites. The fibers can be used in conjunction with conventional materials used in the production of fibrous blankets, vacuum cast and composite materials as a replacement for conventional refractory ceramic fibers. In the production of fiber-containing papers and felts, the fibers may be used alone or in combination with other materials such as binders and the like. The fibers are soluble in simulated physiologic lung fluid, thus reducing concerns about fiber inhalation.

Methods of insulating an article with an insulating material are also provided. According to the method of insulating an article, an insulating material is disposed on, in, near or around the article to be insulated, the insulating material having a working temperature up to at least 1000 ℃ or more, retaining mechanical integrity up to a use temperature, and being non-durable in physiological fluids. The insulation material used in the method of insulating an article comprises the fiberization product of a melt whose ingredients comprise silica, magnesia, a lanthanum-or lanthanide-containing compound, and optionally zirconia.

High temperature resistant, refractory glass fibers are provided that can be easily manufactured from a melt having a viscosity suitable for blowing or spinning the fibers and that are not durable in physiological fluids.

High temperature resistant refractory glass fibers are not durable in physiological fluids and exhibit good mechanical strength up to operating temperatures.

High temperature resistant refractory glass fibers are not durable in physiological fluids and exhibit low shrinkage at use temperatures.

Examples

By fibre blowing from a mixture comprising silica, magnesia and 1 wt% La₂O₃Producing fibers from a melt of the ingredients of (a). The shrinkage characteristics of the fibers were tested by wetting the fibers into a mat and measuring the dimensions of the mat before and after heating the shrinkage mat in an oven for a fixed time.

The shrink pad is prepared by mixing blown fibers, phenolic binder and water. The mixture of fiber, binder and water is poured into a sheet forming die and the water is allowed to drain through the bottom of the die. Pieces of 3 inches x5 inches were cut from the pad and used in the shrinkage test. The length and width of the test pad were carefully measured. The pad was then placed in an oven and brought to a temperature of 1260 ℃ for 24 hours. After heating for 24 hours, the pad was cooled and the length and width were measured again. The linear shrinkage of the test pad was determined by comparing the "front" and "back" dimensional measurements. Test pads comprising fibers made according to the present invention exhibited linear shrinkage of about 4% or less.

The present invention is not limited to the specific embodiments described above, but includes variations, modifications, and equivalent embodiments. The separately disclosed embodiments are not necessarily in the alternative, as various embodiments of the invention may be combined to provide the desired characteristics.

Claims (8)

1. A low shrinkage, high temperature resistant vitreous inorganic fiber having a use temperature of at least 1000 ℃ and above, maintaining mechanical integrity up to the use temperature, and being non-durable in physiological fluids, comprising the fiberization product of greater than 71.25 weight percent silica, from about 14 to about 35 weight percent magnesia, and from greater than 0 to about 6 weight percent of a lanthanide series element containing compound, and optionally zirconia.

2. The fiber of claim 1, comprising the fiberization product of greater than 71.25 to about 86 weight percent silica, from about 14 to about 28.75 weight percent magnesia, and greater than 0 to about 6 weight percent of a lanthanide series element-containing compound.

3. The fiber of claim 2, comprising the fiberization product of about 72 to about 80 weight percent silica, about 21 to about 28 weight percent magnesia, and greater than 0 to about 6 weight percent of a lanthanide series element-containing compound.

4. The fiber of claim 1, wherein the lanthanide-containing compound is selected from the group consisting of lanthanide-containing bromides, lanthanide-containing chlorides, lanthanide-containing fluorides, lanthanide-containing phosphates, lanthanide-containing nitrates, lanthanide-containing nitrites, lanthanide-containing oxides, and lanthanide-containing sulfates.

5. The fiber of claim 4, wherein the lanthanide element-containing compound is La₂O₃。

6. The fiber of any of claims 1 to 5, further characterized by at least one of the following:

(i) wherein the fiberization product comprises less than about 2 weight percent alumina;

(ii) wherein the fiberization product comprises less than about 1 weight percent iron oxide, as Fe₂O₃Counting;

(iii) wherein the fiberization product is substantially free of alkali metal oxide; and

(iv) wherein the fiberization product comprises less than about 1 weight percent calcia.

7. A method of producing the low shrinkage, high temperature resistant vitreous inorganic fiber of any of claims 1 to 6, comprising:

forming a melt of ingredients including silica, magnesia, and a lanthanide element-containing compound, and optionally zirconia; and

fibers are produced from the melt.

8. A method of insulating an article comprising disposing on, in, near or around the article a thermal insulation material having a working temperature up to at least 1000 ℃ or more, maintaining mechanical integrity up to a use temperature, and being non-durable in physiological fluids, the thermal insulation material comprising the fiber of any one of claims 1 to 6.