WO2012001449A1

WO2012001449A1 - Controlled lifetime glasses

Info

Publication number: WO2012001449A1
Application number: PCT/IB2010/001803
Authority: WO
Inventors: Jérôme BLAIZOT; Patrick Moireau
Original assignee: Ocv Intellectual Capital, Llc
Priority date: 2010-06-30
Filing date: 2010-06-30
Publication date: 2012-01-05

Abstract

Glass batch compositions for the formation of biosoluble, controlled lifetime glass fibers are disclosed. The glass compositions contain from about 56 to about 66% by weight SiO2, from about 3 to about 10% by weight Al2O3, from about 2 to about 10% by weight CaO, from O to about 4% by weight MgO, from about 10 to about 20% by weight Na₂O, from about 0.5 to about 15% by weight K2O, and O to about 2% by weight Li₂O. Additionally, the glass composition may have a Na₂O/ Na₂O+K₂O ratio in the glass composition is between 0.5 and 0.8. Also, the glass compositions may have an R₂O-Al₂O₃ value between 15 and 25. The biosoluble fibers have mechanical properties close to conventional, non-soluble glass fibers, have a low hydrolytic strength, and are easily fiberized. The glass fiber may be used with a biosoluble matrix resin to form a biodegradable reinforced composite.

Description

TITLE OF THE INVENTION

CONTROLLED LIFETIME GLASSES

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION

[0001] The present invention relates generally to glass fibers, and more particularly, to glass fibers that have a solubility in water to permit degradation and/or recyclability of the fibers in a natural environment.

BACKGROUND OF THE INVENTION

[0002] Glass fibers are manufactured from various raw materials combined in specific proportions to yield a desired chemical composition. This collection of materials is commonly termed a "glass batch." To form glass fibers, typically the glass batch is melted in a melter or melting apparatus, the molten glass is drawn into filaments through a bushing or orifice plate, and an aqueous sizing composition containing lubricants, coupling agents, and film-forming binder resins is applied to the filaments. After the sizing is applied, the fibers may be gathered into one or more strands and wound into a package or, alternatively, the fibers may be chopped while wet and collected. The collected chopped strands may then be dried and cured to form dry chopped fibers or they can be packaged in their wet condition as wet chopped fibers.

[0003] The composition of the glass batch and the glass manufactured from it are typically expressed in terms of percentages of the components, which are mainly expressed as oxides. Si0₂, A1₂0₃, CaO, MgO, B2O3, Na₂0, ₂0, Fe₂0₃, and minor amounts of other compounds such as Ti0₂, Li₂0, BaO, SrO, ZnO, Zr0₂, P₂Os, fluorine, and SO4 are common components of a glass batch. Numerous types of glasses may be produced from varying the amounts of these oxides, or eliminating some of the oxides in the glass batch. Examples of such glasses that may be produced include R-glass, AR-glass, E-glass, S-glass, A-glass, C-glass, and ECR-glass. The glass composition controls the forming and product properties of the glass. Other characteristics of glass compositions include the raw material cost and environmental impact.

[0004] Environmental awareness is increasing and more concern regarding the environment and biodegradability of products can be seen around the globe. Thermoplastic and thermoset resins are currently used to form plastic products, which are used by consumers and then disposed of by either by incineration or dumping the used plastic product in a landfill. The conventional manufacture of aqueous polymer dispersions is based mainly on processes of direct emulsion polymerization of synthetic monomers of styrene, ethylene, propylene, vinyl alcohol, and acrylamide monomers. These synthetic polymer emulsions are used, for example, to coat cardboard or paper to give them water-resistant properties. The application of these polymer dispersions as a thin coat on the inner face of paper packaging, such as for milk or fruit juices, has led the production of packaging that is difficult to recycle and to biodegrade in conventional landfills.

[0005] Similar problems have been seen with respect to the biosolubility (and biodegradability) of glass fibers. The glass fibers described above may be mixed with a thermoplastic or thermoset resin and transformed to obtain a reinforced composite part. Although certain biodegradable polymers exist that may assist in the natural degradation of the composite part, conventional glass fibers have a low dissolution rate and are therefore not readily biosoluble. As a result, even when a biodegradable polymer is used, scraps of non-soluble and non-degrading material remain in landfills.

[0006] Attempts to increase the dissolution rate of glass fibers so as to produce a wholly dissolvable and degradable composite part have resulted in fibers that have a poor ability to be fiberized and/or fibers that possess insufficient mechanical strength. Accordingly, there remains a need in the art for a cost-effective, stable, and environmentally friendly biosoluble fiber with mechanical properties comparative to conventional fibers and that can be utilized as a reinforcement fiber to form a biosoluble composite product. SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide a glass composition that contains from about 56 to about 66% by weight Si0₂, from about 3 to about 10% by weight A1₂0₃, from about 2 to about 10% by weight CaO, from 0 to about 4% by weight MgO, from about 10 to about 20% by weight Na₂0, from about 0.5 to about 15% by weight K₂0, and 0 to about 2% by weight Li₂0. The phrase "% by weight", as used herein, is intended to be defined as the percent by weight of the total composition. Additionally, the composition may optionally contain trace quantities of other components or impurities. The glass composition may have a Na₂0/ Na₂0+ ₂0 ratio between 0.5 and 0.8 and/or an R₂0-A1₂0₃ value between 15 and 25, where R₂0 is the sum of Na₂0 and K₂0. The glass composition is used to form biosoluble glass fibers that are naturally dissolvable in an aqueous medium. These biosoluble fibers have a dissolution rate greater than about 30 mg/g. As described in more detail below, DGG values correlate to the mass loss of the glass in when placed in water at 98 °C over 5 hours.

[0008] It is another object of the present invention to provide a biosoluble fiber prepared from the composition described above. The biosoluble fibers have mechanical properties comparative to conventional, non-soluble glass fibers and may be produced in a refractory-lined glass melter. The glass fibers have a dissolution rate greater than about 30 mg/g, and in exemplary embodiments, from about 30 mg/g to about 150 mg/g. The biosoluble glasses have the ability to naturally dissolve when in contact with water, such as, for example, in a compost.

[0009] It is also an object of the present invention to provide a biosoluble and biodegradable reinforced composite product that includes a polymer matrix (e.g. , a biodegradable matrix) and a plurality of biosoluble fibers formed from the composition described above. The biosoluble fibers have a resistance to hydrolysis corresponding to a DGG greater than 30 mg/g. The glass fibers reinforcing the polymer matrix are soluble in an aqueous medium. The composite, upon degradation of the polymer and the dissolution of the fibers, forms a compost material in mixture with other components, such as organic scraps or natural fibers, which can be used as an organic additive or as a potting media. In addition, due to the solubility of the glass fibers, the amount of unusable scraps or parts remaining from the composite material (e.g. , in a landfill) is decreased compared to composites formed from conventional, non-soluble glass fibers.

[0010] It is an advantage of the present invention that the biosoluble fibers have mechanical properties close to conventional, non-soluble glass fibers.

[0011] It is another advantage of the present invention that the inventive fibers are easily and fully dissolved in an aqueous medium.

[0012] It is yet another advantage of the present invention that the level of unusable scraps or parts remaining at the end of the life of composite materials formed with the biosoluble fibers is decreased due to the dissolution of the glass fibers.

[0013] It is a further advantage of the present invention that the dissolution rate of the inventive glasses can be modified to achieve a target dissolution rate for a particular application.

[0014] It is also an advantage of the present invention that the glass batch for the biosoluble glasses may be melted in traditional commercially available refractory-lined glass melters.

[0015] The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:

[0017] FIG. 1 is a graphical illustration of the correlation between the degradation of the biosoluble glass fiber and the value for R₂0- A1₂0₃, where R₂0 is the sum of Na₂0 and ₂0. DETAILED DESCRIPTION AND

PREFERRED EMBODIMENTS OF THE INVENTION

[0018] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. All references cited herein are each incorporated by reference in their entireties, including all data, tables, figures, and text presented in the cited references. The terms "biosoluble glass fiber", "biosoluble fiber", "glass fiber", and "fiber" may be used interchangeably herein.

[0019] The present invention relates to a biosoluble glass fiber and a composition for forming the biosoluble glass fiber. As used herein, the term "biosoluble glass fiber" is meant to denote that the glass fiber is dissolved and/or degraded by the action of water or other natural agents. The biosoluble fibers may be used as reinforcement for composite parts. In at least one exemplary embodiment, the biosoluble glass fiber is used in conjunction with biodegradable polymers to form a composite product that is naturally biosoluble and biodegradable over a period of time. The biosoluble fibers have mechanical properties comparative to conventional, non-soluble glass fibers, have a high rate of dissolution in an aqueous medium, low hydrolytic strength (high "DGG" values), and are easily fiberized. In exemplary embodiments, the dissolution rate of the biosoluble fiber is greater than 30 mg/g. As described in more detail below, DGG values correlate to the mass loss of the glass in when placed in water at 98 °C over 5 hours.

[0020] The biosoluble glass fiber is formed from a glass composition having the components and amounts, expressed as percentages by weight, set forth in Table 1. The phrases "percent by weight" and "% by weight), as used in conjunction with the present invention, are intended to be defined as the percent by weight of the total composition. Additionally, as used herein, the terms "weight percent" and "percent by weight" may be used interchangeably and are meant to denote the weight percent (or percent by weight) based on the total composition.

Table 1

Li₂0 0-2

[0021] In another embodiment of the invention, the glass composition includes the components set forth in Table 2.

Table 2

[0022] Additionally, in one or more embodiments, the glass composition may have a

Na₂0/ Na₂0+ ₂0 ratio in the glass composition is between 0.5 and 0.8. Also, one or more of the glass compositions may have an R₂0-A1₂0₃ value between 15 and 25, or between 15 and 21. It is to be noted that R₂0 is the sum of Na₂0 and K₂0. A correlation between the degradation of the glass (DGG), which is discussed in detail below, and the R₂0- AJ₂0₃ value (free alkali content) is shown graphically in FIG. 1. It is to be understood that these ratios are not to be construed as being limited to any particular glass composition described herein.

[0023] Further, it is to be appreciated that impurities or tramp materials may be present in the glass composition without adversely affecting the glasses or the fibers. These impurities may enter the glass as raw material impurities or may be products formed by the chemical reaction of the molten glass with furnace components. Also, the components forming the biosoluble glasses of the present invention are suitable for melting in traditional commercially available refractory-lined glass melters, which are widely used in the manufacture of glass reinforcement fibers.

[0024] In the glass composition, the silica oxide is the primary component. The silica oxide provides a glass network for the fiber and plays a role in the chemical and thermal stability of the formed glass fiber. The mechanical properties of the biosoluble glass fiber are mainly controlled by the content of AI2O3 and MgO in the fiber. The alkali metal oxides (e.g. the free alkali content), namely Na₂0 and ₂0, control the ability of the glass fiber to dissolve under specified conditions (e.g., the dissolution rate). The alkali metals act to break certain covalent bonds present within the glass network. Additionally, the combination of Na₂0 and ₂0 improves the crystallization resistance.

[0025] Fiberizing properties of the glass composition of the present invention include the fiberizing temperature, the liquidus temperature, and delta-T (ΔΤ). The fiberizing temperature is defined as the temperature that corresponds to a viscosity of about 1000 dPa.s. For example, lowering the fiberizing temperature may reduce the production cost of the glass fibers because it allows for a longer bushing life and reduced energy usage. Additionally, by lowering the log 3 temperature, the bushing operates at a cooler temperature and does not quickly "sag". Sag is a phenomenon that occurs in bushings that are held at an elevated temperature for extended periods of time. Thus, by lowering the fiberizing temperature, the sag rate of the bushing may be reduced and the bushing life can be increased.

[0026] Additionally, a lower fiberizing temperature will also permit glass formed with the inventive composition to be melted in a refractory-lined melter instead of conventional high-cost parameters formed of platinum since both its melting and fiberizing temperatures are below the upper use temperatures of many commercially available refractories. Further, the energy necessary to melt the components of the glass composition may be lower than the energy necessary to melt some commercially available glasses. In the present invention, the glass composition has a fiberizing temperature less than about 1200 °C measured at 10³ dPa.s. In exemplary embodiments, the fiberizing temperature is from about 1 100 °C to about 1200 °C, or from about 1 120 °C to about 1 150°C measured at 10³ dPa.s.

[0027] The liquidus temperature is defined as the highest temperature at which equilibrium exists between liquid glass and its primary crystalline phase. At all temperatures above the liquidus temperature, the glass is free from crystals in its primary phase. At temperatures below the liquidus temperature, crystals may form. The liquidus temperature of the inventive composition is desirably no greater than about 1000 °C, and may range from about 800 °C to about 1000 °C, or from about 850 °C to about 1000 °C, or from about 800 °C to about 900 °C.

[0028] Another fiberizing property is delta-T (ΔΤ), which is defined as the difference between the temperature at 1000 dPa.s and the liquidus temperature. A larger ΔΤ offers a greater degree of flexibility during the formation of the glass fibers and helps to inhibit devitrification of the glass (that is, the formation of crystals within the melt) during melting and fiberizing. If the ΔΤ is too small, the molten glass may crystallize within the fiberizing apparatus and cause a break in the manufacturing process. Desirably, the ΔΤ is as large as possible for a given forming viscosity. A larger ΔΤ offers a greater degree of flexibility during fiberizing and helps to avoid devitrification both in the glass distribution system and in the fiberizing apparatus. Additionally, a large ΔΤ reduces the production cost of the glass fibers by allowing for a greater bushing life and a less sensitive forming process. The inventive composition may have a ΔΤ up to about 300 °C, and in exemplary embodiments, from about 150 °C to about 300 °C, or from about 200 °C to about 300 °C.

[0029] In general, glass fibers according to the present invention may be formed by obtaining the raw materials or ingredients and mixing or blending the components in a conventional manner in the appropriate quantities to give the desired weight percentages of the final composition. The mixed batch is then melted in a traditional refractory furnace or melter, and the resulting molten glass is passed along a forehearth and into bushings (e.g., platinum-alloy based bushings) located along the bottom of the forehearth. The operating temperatures of the glass in the furnace, forehearth, and bushing are selected to appropriately adjust the viscosity of the glass, and may be maintained using suitable methods such as control devices. Preferably, the temperature at the front end of the melter is automatically controlled to reduce or eliminate devitrification. The molten glass is then pulled (drawn) through holes or orifices in the bottom or tip plate of the bushing to form glass fibers. The streams of molten glass flowing through the bushing orifices are attenuated to filaments by winding a strand formed of a plurality of individual filaments on a forming tube mounted on a rotatable collet of a winding machine or chopped at an adaptive speed. [0030] The fibers may be further processed in a conventional manner suitable for the intended application. For instance, the glass fibers may be sized with a sizing composition known to those of skill in the art. The sizing composition is in no way restricted, and may be any sizing composition suitable for application to glass fibers. However, in exemplary embodiments, the sizing composition may be a biodegradable sizing composition. The present invention also includes a composite material including biosoluble glass fibers, as described above, in combination with a hardenable matrix material. The matrix material may be any suitable thermoplastic or thermoset resin known to those of skill in the art, such as, but not limited to thermoplastics such as polyesters, polypropylene, polyamide, polyethylene terephtalate, and polybutylene, and thermoset resins such as epoxy resins, unsaturated polyesters, phenolics, vinylesters, and elastomers. These resins can be used alone in or combination. In exemplary embodiments, the matrix material is a biodegradable resin. Non-limiting examples of suitable biodegradable polymers for use in conjunction with the biosoluble fiber include poly(lactic acid), poly(hydroxyalcanoates), poly(caprolactone), poly(hydroxy butyrate), poly(hydroxy butyrate covalerate), starch based polymers, and poly(butylene adipate-co-terephthalate). The biosoluble fiber, when used with a biodegradable sizing composition and a biodegradable polymer matrix, produces a composite product that is, over time, completely biosoluble and biodegradable.

[0031] The inventive biosoluble glass fibers have a hydrolytic resistance (DGG) greater than about 30 mg/g. As used herein, the term "DGG" is intended to denote the mass loss of the glass in water at 98 °C over 5 hours. In exemplary embodiments, the DGG rate is from about 30 mg/g to about 150 mg/g, from about 30 mg/g to about 130 mg/g, from about 30 mg/g to about 120 mg/g, from about 30 mg/g to about 100 mg/g, or from about 40 mg/g to about 80 mg/g, and, in some exemplary embodiments, from about 30 mg/g to about 50 mg/g. It is to be understood that the larger the DGG value, the lower the hydrolytic resistance. The inventive biosoluble glass fibers may be classified as having a "high" dissolution rate (i.e., DGG >30 mg/g).

[0032] The dissolution of the inventive glass fibers in a water environment provides an important advantage in composite waste management by giving the biosoluble glasses the ability to naturally dissolve and/or degrade when in contact with water, such as, for example, in a compost. These composts may then, in turn, advantageously be used in agriculture and in gardening as organic additives for the soil or as potting media. Additionally, some useful elements, such as potassium, may be derived from the glass degradation and utilized as a soil additive. Further, the level of unusable scraps or parts remaining from composite materials at the end of the life of the composite is decreased due to the dissolution of the glass fibers. Thus, there are fewer non-degradable waste products compared to conventional glass reinforced composites.

[0033] Additionally, the dissolution rate of the inventive glasses can be modified to achieve a target dissolution rate for a particular application. For instance, the amount of the alkali metals in the glass composition may be increased or decreased to selectively alter the dissolution rate.

[0034] Having generally described this invention, a further understanding can be obtained by reference to certain specific examples illustrated below which are provided for purposes of illustration only and are not intended to be all inclusive or limiting unless otherwise specified.

[0035] EXAMPLES

[0036] Example 1: Biosoluble Glass Compositions

[0037] Glass compositions according to the present invention were made by mixing reagent grade chemicals in proportioned amounts to achieve a final glass composition with oxide weight percentages set forth in Table 3. The glass was crushed and the glass particles were collected between 10-40 mesh screens. Platinum boats were then filled approximately half full with the obtained crushed glass. The samples were permitted to melt and crystallize for more than 16 hours in a furnace set at a temperature approximately 100 °C higher than the predicted liquidus temperature. Thermocouple readings were recorded and the position and platform numbers were noted. The boats were then removed from the furnace and allowed to cool. After the boats were cooled, the boats were marked and the glass was removed. Next, areas of crystallization to clear glass were located. Under high magnification, areas where crystals were not in multiple layers were located. The distance from the hot end of the boat to the marked area of no crystal growth was measured and recorded. The liquidus temperature was then calculated based on platform temperature readings.

[0038] The liquidus temperature was determined based on the following principles:

• The liquidus temperature is the point under which crystals may be formed • The glass must stay above the liquidus temperature while melting and delivering the glass to the bushing

• The greater the difference between the temperature of the glass during fiber forming and the liquidus temperature, the lower the risk for crystallization (typically operated with a delta-T of 150 °C)

• Liquidus formation depends on glass composition, operating temperatures, width, depth, and insulation of the furnace, and glass redox (e.g., FeO Fe₂0₃)

[0039] Typical crystals that may be formed include: (primary phase at highest temperature)

• Diopside (2CaOMg02Si0₂)

• Anorthite (CaOAl₂0₃ ^«2Si0₂)

• Tridymite (Si0₂)

• Cordierite (MgOAl₂0₃ ^»2Si0₂)

[0040] The ΔΤ was calculated as the difference between the forming temperature and the liquidus temperature. DGG (hydrolytic resistance) was determined by the weight loss in water at

98 °C over 5 hours. The dissolution rate, temperature at 1000 dPa.s, liquidus temperature, and

ΔΤ for the E-glass was included for comparison purposes.

Table 3

Compositions

Table 4

Glass Properties Properties Temperature at Liquidus

DGG Delta T

1000 dPa.s Temperature

Unit mg g °C °C °C

Glass 1 120 1 150 850 300

Glass 2 31 1 120 850 270

E-glass 8.0 1200 1080 120

[0041] As is understood in the art, the above exemplary inventive compositions do not always total 100% of the listed components due to statistical conventions (such as, for example, rounding and averaging) and the fact that some compositions may include impurities that are not listed. Of course, the actual amounts of all components, including any impurities, in a composition always total 100%.

[0042] As shown in Table 4, the biosoluble glass compositions formed by the inventive compositions had dissolution rates far greater than conventional E-glass. Such dissolution rates permit the inventive glasses to quickly dissolve over a short period of time during composting. Also, as apparent from Examples 1 and 2, glass fiber compositions of the invention have advantageous properties, such as wide differences between the liquidus temperatures and the temperatures at 1000 dPa.s (high ΔΤ values). In addition, the inventive glasses possess forming and liquidus temperatures that permit them to be produced in a refractory melter with a concurrent reduction in energy.

[0043] Example 2: Comparative Strength

[0044] Biosoluble glass fibers having the composition of Example 2 set forth in Table 3 were formed in a conventional manner by melting the components in a refractory-lined melter and drawing the fibers through a bushing. The fibers were sized with a conventional sizing composition after they were drawn through the bushing. The fibers were then mixed with a poly(lactic acid) polymer (e.g., a biodegradable polymer) and formed into a composite. A composite formed with conventional E-glass and a poly(lactic acid) polymer was prepared. The two composites were then subjected to tensile strength testing according to the procedure set forth in ISO 527. The results are set forth in Table 5. Table 5

Mechanical Properties Of Composite (PLA Matrix)

[0045] As shown in Table 5, the composite formed utilizing the inventive biosoluble fibers had a tensile strength similar to (i.e., comparative to) that of E-glass. Thus, it can be concluded that the biosoluble fibers as described herein are suitable for use as glass reinforcement in at least the same applications as conventional E-glass fibers.

[0046] The invention of this application has been described above both generically and with regard to specific embodiments. Although the invention has been set forth in what is believed to be the preferred embodiments, a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure. The invention is not otherwise limited, except for the recitation of the claims set forth below.

Claims

1. A composition for preparing biosoluble fibers, said composition comprising the following constituents, expressed in percent by weight of the total composition:

Si0₂ in an amount from 56-66%;

A1₂0₃ in an amount from 3-10%;

CaO in an amount from 2- 10%;

MgO in an amount from 0-4%;

Na₂0 in an amount from 10-20%;

K₂0 in an amount from 0.5-15%; and

Li₂0 in an amount from 0-2%.

2. The composition of claim 1 , wherein said glass composition has a Na₂0/ Na₂0+K₂0 ratio between 0.5 and 0.8.

3. The composition of claim 1, wherein said glass composition has an R₂0-A1₂0₃ value between 15 and 25, where R₂0 is the sum of Na₂0 and K₂0.

4. The composition of claim 1 , wherein the fiberizing temperature is less than about 1200 °C measured at 10³ dPa.s.

5. The composition of claim 1, wherein the liquidus temperature of the inventive composition is no greater than about 1000 °C.

6. The composition of claim 1, wherein said composition has a ΔΤ of up to about 300 °C.

7. A biosoluble fiber prepared from a composition comprising the following constituents, expressed in percent by weight of the total composition: Si0₂ in an amount from 56-66%;

A1₂C»3 in an amount from 3-10%;

CaO in an amount from 2-10%;

MgO in an amount from 0-4%;

Na₂0 in an amount from 10-20%;

K₂0 in an amount from 0.5-15%; and

Li₂0 in an amount from 0-2%,

wherein said fiber has a resistance to hydrolysis of greater than 30 mg/g.

8. The fiber of claim 7, wherein said biosoluble fiber has a resistance to hydrolysis (DGG) between about 30 mg/g and about 150 mg/g.

9. The fiber of claim 7, wherein said glass composition has an R₂0-A1₂<¾ value between 15 and 25, where R₂0 is the sum of Na₂0 and K₂0.

10. The fiber of claim 7, wherein said hydrolytic resistance is altered to meet a particular application by varying the amounts of Na₂0 and K₂0 in said composition.

1 1. The fiber of claim 7, wherein said glass composition has a Na₂0/ Na₂0+K₂0 ratio between 0.5 and 0.8.

12. The fiber of claim 7, wherein the fiberizing temperature from about 1100 °C to about 1200 °C measured at 10³ dPa.s.

13. The fiber of claim 12, wherein the liquidus temperature of the inventive composition is from about 800 °C to about 1000 °C.

14. The fiber of claim 7, wherein said composition has a ΔΤ from about 150 °C to about 300 °C.

15. A biosoluble and biodegradable reinforced composite product comprising: a polymer matrix; and

a plurality of biosoluble fibers, said biosoluble fibers being formed from a composition containing the following components, expressed in percent by weight of the total composition:

Si0₂ in an amount from 56-66%;

A1₂0₃ in an amount from 3-10%;

CaO in an amount from 2-10%;

MgO in an amount from 0-4%;

Na₂0 in an amount from 10-20%;

K₂0 in an amount from 0.5-15%; and

Li₂0 in an amount from 0-2%.

16. The reinforced composite product of claim 15, wherein said fiber has a resistance to hydrolysis of greater than 30 mg/g.

17. The reinforced composite product of claim 16, wherein said polymer matrix is a biodegradable polymer matrix.

18. The reinforced composite product of claim 17, wherein said composite product forms a compost material upon degradation of said polymer and dissolution of said fibers.

19. The reinforced composite product of claim 18, wherein said compost material is used as an organic additive for soil or as a potting media.

20. The reinforced composite product of claim 16, wherein said fiber dissolves naturally in water.