JP2009522461A - Ceramic oxide fiber - Google Patents

Abstract

  A substantially continuous ceramic oxide fiber tow having a sizing agent. The tow according to the invention is useful, for example, in the production of metal matrix wires.

Description

  The present invention relates to ceramic oxide fibers, and more specifically to ceramic oxide fibers having a sizing agent.

  In general, substantially continuous ceramic oxide fibers are known. Examples include polycrystalline alumina fibers such as those sold under the trade name “NEXTEL 610” by 3M Company of St. Paul, Minnesota, and the trade name “NEXTEL” by 3M Company. 440 ”“ NEXTEL 550 ”and“ NEXTEL 720 ”, such as those sold as aluminosilicate fibers, as well as those sold by 3M under the trade name“ NEXTEL 312 ” Aluminoborosilicate fibers. These continuous fibers are incorporated into various metal matrix composites (eg, aluminum and titanium) and polymeric matrix composites (eg, epoxy) to reinforce and reinforce these composites.

  It is desirable to maintain the strength of the composite. The strength of the composite is increased by having continuous fibers with as few breaks as possible. One cause of breaks occurs when unwinding continuous fibers from the spool and when the fibers break or fall off, which is commonly referred to as “strip back”. It is desirable to eliminate, minimize, or at least reduce these breaks produced during the unwinding process, thereby allowing the production of increased strength metal and polymer matrix composites.

In one aspect, the present invention provides a tow of ceramic oxide fibers that is substantially continuous in heat resistance (ie, its integrity or usefulness is maintained at temperatures ranging from 820 ° C to 1400 ° C), The ceramic oxide fiber has an outer surface, and at least a portion of the outer surface of at least some ceramic oxide fibers has a sizing agent therein. The sizing agent contains a composition represented by the following formula.
R′O— (RO) _n —H
Wherein R ′ is selected from C _x H _{2x + 1} (wherein x is 1 to 8) or —H, and R is — (C _y H _2y ) — (linear or branched) (Wherein y is 1 to 4), and —CH ₂ —O— (CH ₂ ) _m — (wherein m is 2 to 5); n is selected such that the number average molecular weight is in the range of 500 g / mol to 7,000,000 g / mol. Typically, the number average molecular weight is in the range of 500 g / mol to 3,000,000 g / mol (in some embodiments, 500 g / mol to 600,000 g / mol, 500 g / mol to 400,000 g / mol, 500 g / Mol to 300,000 g / mol, or even in the range of 4,000 g / mol to 40,000 g / mol). Usually, the sizing agent provides a weight gain in the range of 0.5 to 10% by weight.

“Continuous fiber” refers to a fiber having a length of at least 30 m. In some embodiments, the heat resistant fiber is crystalline (ie, exhibits a discernable powder X-ray diffraction pattern). In some embodiments, the fiber is at least 50% by weight (in some embodiments 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99 or 100 Even crystalline). In some embodiments, the refractory ceramic oxide fibers (including crystalline ceramic oxide fibers) are (a) at least 40% by weight (in some embodiments, 50, based on the total oxide content of each fiber). 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99 or even 100) Al ₂ O ₃ , or (b) 40 wt% or less in total (some In embodiments, 35, 30, 25, 20, 15, 10, 5, 4, 3, ₂ , 1, 0.5, 0.1, or even 0)) SiO ₂ , Bi ₂ O ₃ , B ₂ O ₃ , P ₂ O ₅ , GeO ₂ , TeO ₂ , As ₂ O _3, and V ₂ O ₅ .

  Sizing agents have been found to provide lubricity and protect the fiber strands during processing. For example, when using fibers as a reinforcement for a metal matrix composite, the sizing agent is typically removed in a step prior to applying the metal to the fibers. The sizing agent can be removed, for example, by burning the sizing agent away from the fibers.

Examples of suitable heat resistant ceramic oxide fibers include alumina fibers, aluminosilicate fibers, aluminoborate fibers, aluminoborosilicate fibers, zirconia-silica fibers, and combinations thereof. Suitable crystalline refractory ceramic oxide fibers include alumina fibers, aluminosilicate fibers, aluminoborate fibers, aluminoborosilicate fibers, zirconia-silica fibers, and combinations thereof. Examples of suitable non-crystalline heat resistant ceramic oxide fibers include aluminoborosilicate fibers, zirconia-silica fibers, and combinations thereof. In some embodiments, the fiber is at least 40% by volume (in some embodiments 50, 60, 65, 70, 75, 80, 85, 90, 95, 96, even if the 97, 98 and 99 or 100.) it is desirable containing _Al 2 _{O 3} of. In some embodiments, the fiber is 40-70% by volume, based on the total volume of the fiber (in some embodiments, it may be in the range of 55-70, or even 55-65% by volume). it is desirable to include the _Al 2 _{O 3.}

  Partially crystalline fibers may include a mixture of crystalline ceramic and amorphous phases (ie, the fibers may contain both crystalline ceramic and amorphous phases). Typically, the average fiber diameter of continuous ceramic fibers is at least about 5 μm, more typically from about 5 μm to about 20 μm, and in some embodiments, from about 5 μm to about 15 μm.

Alumina fibers are described, for example, in US Pat. Nos. 4,954,462 (Wood et al.) And 5,185,299 (Wood et al.). In some embodiments, the alumina fibers are polycrystalline alpha alumina fibers, in oxide-based theoretical, based on the total weight of the alumina fibers, Al ₂ O ₃ and 0.2 to 0 over 99 wt% .5 wt% SiO ₂ . In another aspect, some desirable polycrystalline alpha alumina fibers comprise alpha alumina having an average particle size of less than 1 μm (or in some embodiments, even less than 0.5 μm). In another aspect, in some embodiments, the average tensile strength of the polycrystalline alpha alumina fiber as measured according to the tensile strength test described in US Pat. No. 6,460,597 (McCullough et al.). Is at least 1.6 GPa (in some embodiments, at least 2.1 GPa, or even at least 2.8 GPa). A representative alpha alumina fiber is sold under the trade designation “NEXTEL 610” by 3M Company of St. Paul, Minnesota.

  Aluminosilicate fibers are described, for example, in US Pat. No. 4,047,965 (Karst et al.). Exemplary aluminosilicate fibers are sold under the trade names “Nextel 440”, “Nextel 550”, and “Nextel 720” by 3M Company of St. Paul, Minnesota.

  Aluminoborate and aluminoborosilicate fibers are described, for example, in US Pat. No. 3,795,524 (Sowman). A representative aluminoborosilicate fiber is sold by 3M under the trade name “Nextel 312”.

Zirconia-silica fibers are described, for example, in US Pat. No. 3,709,706 (Sowman).
Tows are known in the fiber art and usually comprise a plurality of (individual) undisclosed fibers (usually at least 100 fibers, more typically at least 400 fibers). In some embodiments, the tow comprises at least 780 individual fibers per tow, and in some cases at least 2600 individual fibers per tow, or at least 5200 individual fibers per tow. Various ceramic fiber tows are available in various lengths, including 300 m, 500 m, 750 m, 1000 m, 1500 m, and more. The fibers may have a cross-sectional shape that is round, oval or dogbone.

The tow according to the present invention is
Providing a tow of substantially continuous ceramic oxide fibers, each ceramic oxide fiber having an outer surface;
Coating at least a portion of the outer surface of at least some ceramic oxide fibers with an aqueous sizing;
And a method including a step of removing at least a part of water. The sizing agent contains a composition represented by the following formula.
R′O— (RO) _n —H
In the formula, R ′ is selected from C _x H _{2x + 1} (wherein x1 is 1 to 8) or —H, and R is — (C _y H _2y ) — (wherein y is 1 to 4). ), And —CH ₂ —O— (CH ₂ ) _m — (wherein m is 2 to 5), n is a number average molecular weight of 500 g / mol to 7 Selected to be in the range of 1,000,000 g / mol. Typically, the number average molecular weight is in the range of 500 g / mol to 3,000,000 g / mol (in some embodiments, 500 g / mol to 600,000 g / mol, 500 g / mol to 400,000 g / mol, 500 g / Mol to 300,000 g / mol, or even in the range of 4,000 g / mol to 40,000 g / mol).

  Suitable sizing agents include poly (tetramethylene oxide) (for example, from Invista, Wichita, Kansas, under the trade name "TERATHANE 2900" (number average molecular weight 2,900 g / mol). Available), polyethylene glycol (for example, Clariant GmbH, Frankfurt, Germany, Functional Chemicals Division, trade name "POLYGLYKOL 35000" (number average molecular weight 35,000 g / mol) "Polyglycol (POLYGLYKOL) 4000S" (number average molecular weight 4000 g / mol), "Polyglycol (POLYGLYKOL) 8000S" (number average molecular weight 8000 g / mol), "Polyglycol (POLYGLYKOL) 1500S" (number average molecular weight 1500 g / mol) ) And high number average molecules Polyethylene oxide materials (for example, trade names “POLYOX WSR N-3000” (number average molecular weight 400,000 g / mol), “POLYOX WSR N-750” from Dow Chemical Company of Midland, Michigan) Number average molecular weight 300,000 g / mol), and “POLYOX WSR-301” (available as number average molecular weight 4,000,000 g / mol).

  Water soluble sizing agents such as poly (ethylene glycols) can be dissolved in water to provide aqueous sizing agents. The concentration of the water-soluble sizing agent in the aqueous sizing agent can be selected as necessary. Typically, such aqueous sizing agents are prepared by mixing water-soluble sizing agents and water, and aqueous sizes comprising 1-30% by weight, in some embodiments 1-10% by weight, water-soluble sizing agents. Provide the agent.

  If a material that is not suitable in water (eg poly (tetramethylene oxide)) is used, the aqueous sizing agent is emulsified. Such an emulsion can be produced using a surfactant. Usually, the amount of surfactant used in the preparation of the emulsion is in the range of 0.5 to 10% by weight of the material to be emulsified, although amounts of surfactant outside this range may also be useful. . Usually, the emulsion is in the range of 5-50% solids by weight. If the percent solids of the emulsion is greater than the desired value, it may be diluted with water.

  In general, in the art, a sizing agent is (a) sufficient strength to bind the fibers in the tow together into a coherent bundle, (b) the fibers / tows do not stick to the equipment and yarn guide, and Good lubrication / peeling properties, such as having good lubricity to reduce friction and adhesion to surfaces that come into contact with the tow during processing, and (c) residues on the fibers at relatively low or medium temperatures (eg 700 ° C.) It has been recognized that it provides the ability to oxidize rapidly without leaving a (eg carbon-containing residue). The latter is particularly desirable in embodiments of the metal matrix wire manufacturing method, where the sizing agent is usually easily removed in a relatively short time (eg, less than 30 seconds) by heating the tow at a relatively low or medium temperature. . Sizing removal is facilitated by injecting an oxidizing gas (eg, air) into the location where the sizing agent is oxidized. The desired flow rate of the oxidizing gas will depend on the particular situation (eg, specific sizing agent, sizing amount, fiber speed, temperature, hot zone length, etc.), but typical flow rates include about Examples include flow rates ranging from 5 L / min to about 10 L / min.

  Further, the sizing agent defined in the present invention can be effectively applied to fibers (eg, fibers having a temperature in the range of about 15 ° C. to 200 ° C.), which is applied to the fibers as they exit the sintering furnace. Including.

  The tow according to the invention is useful, for example, in the production of metal matrix composite wires. Exemplary metal matrix materials include aluminum, zinc, tin, magnesium, and alloys thereof (eg, aluminum and copper alloys). Manufacturing techniques for metal matrix composite wires are known in the art, for example, US Pat. Nos. 5,501,906 (Deve), 6,180,232 (McCullough et al.). 6,245,425 (Makalac et al.), 6,336,495 (Makalac et al.), 6,544,645 (Makalac et al.), 6,447,927 (Makalac) No. 6,460,597 (Macarok et al.), No. 6,329,056 (Dieve et al.), No. 6,344,270 (Macarok et al.), No. 6,485,796. (Carpenter et al.), 6,559,385 (Johnson et al.), 6,796,365 (Makalac et al.), 6,723,451 (Makalac et al.), Same , 692, 842 (Makalac et al.), 6,913,838 (Makalac et al.), US Patent Application No. 10 / 403,643 filed on March 31, 2003, filed on February 13, 2004. US Patent Application Publication No. 2005/0178000, US Patent Application Publication No. 2005/0181228 filed on February 13, 2004, US Patent Application Publication No. 2005/0279526 filed on June 17, 2004, June 2004. And those discussed in U.S. Patent Application Publication No. 2005/0279527 and U.S. Patent No. 7,093,416, both filed on the 17th.

  Embodiments of metal matrix composite wires made from sized fibers according to the present invention were made from sizing-free fibers utilized in the present invention (including fibers sized with other sizing agents) Stronger (eg, about 2-8%) was found compared to metal matrix composite wires.

  The advantages and embodiments of the present invention are further illustrated by the following examples, but the specific materials and their amounts listed in these examples, as well as other conditions and details, should unduly limit the present invention. Should not be interpreted. All percentages and percentages are by weight unless otherwise specified.

Example 1
52.2 kg (115 lbs.) Of solid poly (tetramethylene oxide) (number average molecular weight 2900 g / mol; obtained from Invista, Wichita, Kansas, under the trade designation “Teratan 2900”) at 60 ° C. (140 ° F.) It was melted by placing it overnight in a heated oven. A 284 L (75 gallon) glass-lined water jacketed vessel with a stirrer was brought to 60 ° C. (140 ° F.). The stirrer was set at 80 rpm, and molten poly (tetramethylene oxide) (“terratan 2900”) was placed in the reactor. 52.2 kg (115 lbs.) Of ethyl acetate (obtained from Sigma-Aldrich, Milwaukee, Wis.) Followed by 8.7 kg (19.1 lbs.) Of octadecylmethyl (polyoxyethylene [15]) ammonium chloride (Obtained under the trade name “ETHOQUAD 18/25” from Akzo Nobel, Chicago, Ill.) Was added to the reactor.

  A second, 284 L (75 gallon) glass lined water jacketed vessel with a stirrer (80 rpm) was brought to 60 ° C. (140 ° F.). Filter through 114 kg (253 lbs.) Deionized water (0.2 micron filter (obtained from CC Day Co., Minneapolis, Minn .; part number 25-10110-002-01-WG)) Was added to the reactor. The stirrer speed was increased to 100 rpm. When the temperature of both the reactor and the vessel reached 60 ° C. (140 ° F.), the nitrogen pressure in the vessel was raised and the contents of the first reactor were poured into the second reactor.

  Water inlet connection of a two-stage homogenizer (70-M-310-TBS type; obtained from Manton-Gaulin Manufacturing Co., Everett, Mass .; flushed with deionized water) The part was attached to the inlet of a homogenizer equipped with a tube and a 0.2 micron filter (obtained from CC Day Co .; part number 25-10110-002-01-WG). A 25 μm filter cartridge (obtained from CC Day Co .; part number SWF-25-RYA10T) was installed between the outlet of the reactor and the inlet connection of the homogenizer. The operating pressure of the homogenizer was set to 20.7 MPa (3000 psig) and the mixture was delivered at 20.7 MPa (3000 psig). When the output from the homogenizer became a pale white emulsion without solids, the output was directed to a 208 L (55 gallon) drum with a polyethylene liner.

  When the white emulsion passed the homogenizer for the second time, the output was again directed to a 208 L (55 gallon) drum with a polyethylene liner. A condensate decanter was attached to the first reactor and deionized water was flushed and washed before the pale white emulsion entered the (clean) container. The stirrer was at 60 rpm and the jacket temperature was set at 38 ° C. (100 ° F.). The reactor was then closed and the contents were drawn under reduced pressure (8 kPa (60 mmHg)). Gently (5.3 kPa (40 mm Hg)) reduced pressure to collect ethyl acetate distillate in a decanter to minimize excessive foaming. Once 45.4 kg (100 lbs.) Of ethyl acetate had collected, distilled The reactor was cooled to 21 ° C. (70 ° F.) and the resulting emulsion was obtained from a 25 μm cartridge filter (CCDay Co.); part number SWF-25- RYA10T) was discharged into a 19 L (5 gallon) polyethylene-lined bucket and covered.

The resulting emulsion is treated with alpha alumina fiber tow (10,000 denier; St. Paul, Minn.) Under the trade designation “NEXTEL Ceramic Oxide” using a coating station according to the following procedure. Fiber 610 * "). As described above, the “terratan 2900” emulsion was diluted with deionized water to a 5% “terratan 2900” emulsion and placed on the sizing tray of the coating station. Lift the emulsion with a sizing roll by immersing it in the coating tray. Sizing was coated onto a fiber tow by passing the tow over a sizing roll at a speed of 34.7 m / min (114 ft / min). The speed of the sizing agent application roll was set so that the coating amount of the sizing agent net was 1.5%. The coated fiber tow was wound 12 times around a dry can (6 inches of chrome coated steel roll heated to 100 ° C.) and then wrapped around a paper tube.
* The fibers used were not sized before application of the emulsion. Fibers sold by 3M are usually sold in a sized state. Such sizing can usually be removed by heating the fibers to at least 700 ° C. for 5 minutes.

The amount of sizing agent applied to the fiber tow weighs 1 meter (3 feet) of a sized tow piece (w _initial ) and places the sized tow piece in a 700 ° C. oven for 5 minutes, Measurements were taken by removing the sample from the furnace, cooling to room temperature, and then reweighing (w _final ) the sample. The weight% (S _w ) of the applied sizing agent was calculated using the following formula:

  The weight gain of the dried sizing was about 2% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

(Example 2)
2858 g of deionized water was placed in a 4 L (1 gallon) glass jar. Insert an overhead mixer with a Cowl's blade mixer into a glass jar, set to 500 rpm, 150 g polyethylene glycol (number average molecular weight 300,000 g / mol; product from Dow Chemical Company, Midland, Michigan) The name "POLYOX WSR N-750") was added slowly (over about 30 minutes) while vortexing with a Cowles blade. The resulting mixture was obtained on a platform shaker table (obtained under the trade designation “INNOVA 2000” from New Brunswick Scientific Co. Inc., Edison, NJ). For about 60 hours.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing agent was about 1% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

(Example 3)
Example 3 shows that 3 g of polyethylene glycol (number average molecular weight 1500 g / mol; obtained under the trade name “PEG 1500” from Sigma Aldrich, Milwaukee, Wis.) Was added to deionized water prior to polyethylene glycol. Except as described in Example 2.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing was about 1.5% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

(Example 4)
Example 4 is the same as Example 2 except that the polyethylene glycol was replaced with 150 g of polyethylene glycol (number average molecular weight 20,000 g / mol; obtained from Sigma-Aldrich under the trade name “PEG 20,000”). Prepared as described in The material obtained was a clear solution.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing agent was about 1% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

(Example 5)
Into a 3.8 L (1 gal) glass jar was placed 2850 g of deionized water. An overhead mixer with a Cowl's blade mixer was inserted into a glass jar, set at 500 rpm, 150 g polyethylene glycol (number average molecular weight 35,000 g / mol; Clariant, Mount Holly, NC) (Obtained under the trade name “POLYGLYKOL 35000” from Clariant Corporation) was added slowly (over about 10 minutes) while vortexing with a Cowles blade. The obtained substance was a colorless and transparent solution.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing agent was about 1% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

(Example 6)
In a 6 liter stainless steel beaker, 2970 g of deionized water is placed and a mixer (Charles Ross & Son Co., Hauppauge, New York) ROSS MIXER EMULSIFIER) ”# ME100L type) was inserted into a beaker. The mixer was set at 5000 rpm and 30 g of polyethylene glycol (number average molecular weight 4,000,000 g / mol; obtained from Dow Chemical Company under the trade name “Polyox WSR-301”) slowly (over about 15 minutes) Added to. The resulting mixture was placed on a shaker table (see Example 2, 125 rpm) for 12 hours.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing was about 1.5% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

(Example 7)
In a 6 L stainless steel beaker, 2985 g of deionized water was placed. An overhead mixer with a Cowl's blade mixer was inserted into a glass jar, set to 500 rpm, and 15 g polyethylene glycol (number average molecular weight 7,000,000 g / mol; from Dow Chemical Company, trade name “ Polyox WSR-303 ") was slowly added to the water (over about 30 minutes). The resulting mixture was placed on a shaker table (see Example 2, 125 rpm) for 12 hours.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing was about 2% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

(Example 8)
A 6L stainless steel beaker was charged with 2850 g of deionized water and a mixer with a Ross screen head ("ROSS MIXER EMULSIFIER") was inserted into the beaker. The mixer was set to 5000 rpm, the water was heated to 60 ° C., and 30 g of polyethylene glycol (“Polyox WSR N-750”) was added slowly (over about 15 minutes) to the water. The resulting mixture was placed on a conventional roller table (about 40 rpm) for 12 hours to obtain a cloudy solution.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing agent was about 1.3% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

Example 9
A 6L stainless steel beaker was charged with 2850 g of deionized water and a mixer with a Ross disperser blade ("Ross mixer emulsion") was inserted into the beaker. The mixer was set at 5000 rpm and 150 g of polyethylene glycol (number average molecular weight 400,000; obtained from Dow Chemical Company under the trade name “Polyox WSR N-3000”) was slowly added to the water (over about 30 minutes). . A clear solution was obtained.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing was about 1.5% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

(Example 10)
In Example 10, polyethylene glycol (number average molecular weight: 4000 g / mol; obtained under the trade name “POLYGLYKOL 4000S” from Clariant) was added to deionized water instead of “PEG 1500” polyethylene glycol. Except as described in Example 3.

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing agent was about 1.3% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

Example 11
In Example 11, in place of “polyglycol (POLYGLYKOL) 4000S” polyethylene glycol, polyethylene glycol (number average molecular weight 8000 g / mol; obtained from Clariant under the trade name “POLYGLYKOL 8000S”) as deionized water. Prepared as described in Example 10 except that was added to

  The resulting solution was coated on an alumina fiber tow as described in Example 1. The weight gain of the dried sizing was about 2% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

Example 12
Example 12 was performed except that 147 g of “Polyox WSR N-750” and 3.02 g of “PEG 1500” were added to deionized water instead of 150 g of “Polyox WSR N-750” polyethylene glycol. Prepared as described in Example 2. The weight gain of the dried sizing agent was about 1.2% by weight. The sizing agent was visually observed and the fibers disappeared cleanly.

  Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention, but the invention is unduly limited to the illustrated embodiments described herein. It should be understood that it should not.

Claims (8)

A tow of substantially continuous ceramic oxide fibers, each ceramic oxide fiber having an outer surface, at least a portion of the outer surface of at least some of the ceramic oxide fibers having a sizing agent therein A tow comprising the composition represented by the following formula:
R′O— (RO) _n —H
[Where:
R ′ is selected from C _x H _{2x + 1} (wherein x is 1 to 8) or —H;
R is _- (wherein, y is 1-4.), And _{-CH 2 -O- (CH 2) m} - - (C y H 2y) ( in the formula, m is 2-5. ) Selected from the group consisting of
n is selected such that the number average molecular weight is in the range of 500 g / mol to 7,000,000 g / mol. ]   The tow of claim 1, wherein the substantially continuous ceramic oxide fiber is crystalline.   The tow according to claim 1, wherein the substantially continuous ceramic oxide fiber is selected from the group consisting of crystalline alumina fiber, crystalline aluminosilicate fiber, crystalline boron aluminosilicate fiber, and combinations thereof.   The tow according to claim 1, wherein n is selected such that the number average molecular weight is in the range of 500 g / mol to 3,000,000 g / mol.   The tow according to claim 1, wherein n is selected such that the number average molecular weight is in the range of 500 g / mole to 400,000 g / mole. A method of providing a substantially continuous ceramic oxide fiber tow according to claim 1, wherein the method comprises:
Providing substantially continuous ceramic oxide fibers, each ceramic oxide fiber having an outer surface;
Coating at least a portion of the outer surface of at least some of the ceramic oxide fibers with an aqueous sizing, wherein the sizing comprises a composition represented by the formula:
_{R 1 'O- (R 1 O} ) n1 -H
[Where:
R ₁ ′ is selected from C _x1 H _{2x1 + 1} (wherein x1 is 1 to 8) or —H;
R ₁ is — (C _y1 H _2y1 ) — (wherein y ₁ is 1 to 4), and —CH ₂ —O— (CH ₂ ) _m1 — (where m ₁ is 2 to 5). And n is selected such that the number average molecular weight is in the range of 500 g / mole to 7,000,000 g / mole. ]
Removing at least a portion of the water.   The method of claim 6, wherein the aqueous sizing agent is a solution.   The method of claim 6, wherein the aqueous sizing agent is an emulsion.