WO2024097047A1

WO2024097047A1 - Enhanced tensile strength low wall drag ceramic precursor paste with polyethylene glycol

Info

Publication number: WO2024097047A1
Application number: PCT/US2023/035752
Authority: WO
Inventors: Keith Norman BUBB
Original assignee: Corning Incorporated
Priority date: 2022-10-31
Filing date: 2023-10-24
Publication date: 2024-05-10

Abstract

An enhanced tensile strength low wall drag ceramic-forming batch mixture of an inorganic component comprised of inorganic particles, a cellulosic binder component, a lubricant component comprised of fatty acid and/or synthetic oil, a liquid vehicle component comprised of water, and polyethylene oxide. A method of manufacturing a ceramic-forming batch mixture wherein a composition of a starting low wall drag ceramic-forming batch mixture is adjusted by substituting a portion of its methylcellulose type binder with polyethylene oxide, and optionally reducing the amount of lubricant in the mixture while the resulting batch mixture is also in a low wall drag state, and has improved tensile property.

Description

ENHANCED TENSILE STRENGTH LOW WALL DRAG CERAMIC PRECURSOR PASTE WITH POLYETHYLENE GLYCOL

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63/420905 filed on October 31, 2022, the content of which is relied upon and incorporated herein by reference in its entirety.

BACKGROUND

Field

[0002] The present specification relates to ceramic pastes (ceramic and/or ceramicforming pastes), methods of making such pastes, and methods of making self-standing extruded articles by extruding such pastes.

Technical Background

[0003] Ceramic products in a wide range of fields from refractory tubing to automotive and diesel exhaust filters and catalytic converter substrates can be manufactured by extrusion of pastes. The cost of such products can be driven by the rate of production of quality products.

SUMMARY

[0004] Aspects of the disclosure pertain to porous filter bodies and methods for their manufacture and use.

[0005] In one aspect, a ceramic-forming batch mixture is disclosed herein comprising: an inorganic component comprised of inorganic particles, a cellulosic binder component, a lubricant component comprised of fatty acid and/or synthetic oil, a liquid vehicle component comprised of water, and polyethylene oxide.

[0006] In embodiments, a ratio of the amounts (in wt%) of the cellulosic binder component to the polyethylene oxide is between 0.5: 1 and 1.5: 1. [0007] In embodiments, the cellulosic binder component comprises a methylcellulose constituent comprised of one or more of methylcellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, carboxylmethyl cellulose, and related cellulosic compounds.

[0008] In embodiments, the cellulosic binder component consists of a methylcellulose constituent.

[0009] In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.75: 1 and 1.25: 1, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.80: 1 and 1.20: 1, or the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.90: 1 and 1.10: 1, or the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.95: 1 and 1.05: 1, or the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is about 1 : 1.

[0010] In embodiments, the batch mixture comprises methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles.

[0011] In embodiments, the cellulosic binder component is methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles.

[0012] In embodiments, the batch mixture is in a low wall drag state.

[0013] In embodiments, the PEO has a molecular weight of 1 million or more.

[0014] In embodiments, the PEO has a molecular weight of 1-2 million, such as 2 million or more, such as 5 million or more, such as 7 million or more.

[0015] In embodiments, the synthetic oil comprises a polyalphaolefin.

[0016] In embodiments, the PEO has a molecular weight of 5 million or less, such as 2 million or less, such as 1 million or less.

[0017] In another aspect, a method of manufacturing a ceramic-forming batch mixture is disclosed herein, the method comprising: adjusting a composition of a starting low wall drag ceramic-forming batch mixture (“starting batch mixture”), the mixture comprising an inorganic component comprised of inorganic particles, a cellulosic binder component, a lubricant component comprised of fatty acid and/or synthetic oil, and a liquid vehicle component comprised of water, adding PEO to the low wall drag mixture on a weight % basis with respect to the inorganic particles, and reducing either the amount of the cellulosic binder component on a weight % basis with respect to the inorganic particles.

[0018] In embodiments, extrudate of the resulting batch mixture extruded through an extrusion die under extrusion conditions has a higher tensile strength than extrudate of the starting batch mixture extruded through the same extrusion die under the same extrusion conditions. In embodiments, the resulting batch mixture has a higher strain at break than the starting batch mixture under the same test conditions. In embodiments, the resulting batch mixture is in a lower wall drag state than the starting low wall drag batch mixture.

[0019] In embodiments, a ratio of the amounts (in wt%) of the cellulosic binder component to the polyethylene oxide is between 0.5: 1 and 1.5: 1.

[0020] In embodiments, the cellulosic binder component comprises a methylcellulose constituent comprised of one or more of methylcellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, carboxylmethyl cellulose, and related cellulosic compounds.

[0021] In embodiments, the cellulosic binder component consists of a methylcellulose constituent.

[0022] In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.75: 1 and 1.25: 1, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.80: 1 and 1.20: 1, or the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.90: 1 and 1.10: 1, or the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.95: 1 and 1.05: 1, or the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is about 1 : 1.

[0023] In embodiments, the batch mixture comprises methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles. [0024] In embodiments, the cellulosic binder component is methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles.

[0025] In embodiments, the batch mixture is in a low wall drag state.

[0026] In embodiments, the PEO has a molecular weight of 1 million or more.

[0027] In embodiments, the PEO has a molecular weight of 1-2 million, such as 2 million or more, such as 5 million or more, such as 7 million or more.

[0028] In embodiments, the synthetic oil comprises a polyalphaolefin.

[0029] In embodiments, the PEO has a molecular weight of 5 million or less, such as 2 million or less, such as 1 million or less.

[0030] Additional features and advantages will be set forth in the detailed description, which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, comprising the detailed description, which follows, the claims, as well as the appended drawings.

[0031] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 shows a cordierite-forming batch mixture, composition Ex. A, which was adjusted such that in a modified/adjusted composition of cordierite-forming batch mixture Ex. B, a portion of the methylcellulose (Methocel) was replaced by polyethylene oxide (PEO), which also enabled a reduction in the amount of lubricant in a mixture.

[0033] FIG. 2 graphically illustrates capillary rheometer measurements (wall shear stress Tw plotted versus Rate of extrusion, for 3 separate paste temperature conditions: 20 °C, 30 °C, and 40 °C) of paste of the modified composition of FIG. 1 Ex. B having 1% PEO by weight of inorganics vs. the unmodified starting composition Ex. A having 0% PEO, including best fit curves for each.

[0034] FIG. 3 graphically illustrates capillary rheometer die pressure Pdie plotted versus Penetrometer reading, for compositions Ex. A and Ex. B of FIGS. 1-2.

[0035] FIG. 4 graphically illustrates capillary rheometer wall shear stress Ty plotted versus Strain at Break (SAB), for compositions Ex. A and Ex. B of FIGS. 1-3.

[0036] FIG. 5 graphically illustrates extrusion pressure in a twin screw extruder for compositions Ex. A and Ex. B of FIGS. 1-4.

DETAILED DESCRIPTION

[0037] Reference will now be made in detail to embodiments of articles for emissions treatment, for example, filtration articles, comprising a plugged honeycomb filter body comprising inorganic deposits disposed on walls defining inlet channels of the plugged honeycomb filter body, the inorganic deposits comprising fumed silica particles, embodiments of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0038] As used herein, “ceramic batch mixture” comprises a mixture which comprises, among other constituents, an inorganic component comprised of either ceramic constituents (e.g. cordierite or silicon carbide) or ceramic-forming precursor constituents (e.g. oxide constituents capable of being transformed into a ceramic material such as cordierite upon firing), or both. The inorganic particles can comprise single-constituent particulates such as cordierite or silicon carbide, or mixtures of oxides or other compounds that are convertible to crystalline ceramic materials upon firing, such as cordierite. Ceramic products may be manufactured by employing such batch mixtures. For example, a method of manufacturing a ceramic body comprises mixing an inorganic (ceramic and/or ceramic-forming) powder component such as a cordierite and/or cordierite forming component, water as the liquid vehicle, a cellulose ether binder, and a lubricant component comprised of a fatty acid constituent and an oil constituent such as a synthetic oil constituent; the method can further comprise extruding the paste through an extrusion die, such as a honeycomb extrusion die, to produce a self-standing, or self-supporting, extrudate body. The extrudate body, or a portion thereof, can be fired to sinter and/or reactively sinter the extruded composition into a ceramic composition. In embodiments, the mixture can be thoroughly blended to form a plasticized ceramic paste, and the method can further comprise pressing or extruding the ceramic paste through an extrusion die to form a self-standing body. In embodiments, the extrusion die is a honeycomb die and the extruded self-standing body is an unfired honeycomb body that retains its extruded shape despite the presence of retained water.

[0039] As used herein, “ceramic paste” comprises a paste which comprises, among other constituents, a liquid vehicle component such as water, and an inorganic component comprised of either ceramic constituents (e.g. cordierite or silicon carbide) or ceramic-forming precursor constituents (e.g. oxide constituents capable of being transformed into a ceramic material such as cordierite upon firing), or both.

[0040] In addition to production rate of extruded ceramic products, the “die life” or footage of batch through an extrusion die before recoating is needed can be a significant cost factor. The rate at which products can be extruded is dependent on die pressure which includes contributions of the “wall drag” induced by the batch being forced through an extrusion die. Reduction of wall drag helps to achieve both higher rates of extrusion and longer die life.

[0041] Low Wall Drag (LWD) ceramic pastes may also comprise a lubricant package, such as a lubricant package of fatty acid and an oil, such as synthetic oil, such as polyalphaolefin. Depending on inorganic component and binder (such as cellulosic ether binder) amounts, the amounts, or ratio, of fatty acid and polyalphaolefin can vary, but while such lubricant package helps to achieve a LWD state for the paste, the lubricant package can also result in a reduced tensile characteristic of the paste. The reduced tensile behavior occurs because the water content in the paste may need to be reduced in order to maintain stiffness (i.e. lubricant addition may displace water), and for aqueous based pastes that comprise a cellulosic ether binder such as methylcellulose, the reduced water content or amount in the paste reduces the hydration of the methylcellulose binder responsible for achieving acceptable tensile properties.

[0042] We have found that low wall drag ceramic precursor batch mixtures, or ceramic pastes, can be imbued with enhanced tensile strength by substituting a portion of cellulosic binder with polyethylene glycol (PEO) while still maintaining a low wall drag state of the ceramic mixture or paste. The methylcellulose constituent can be comprised of one or more of: methylcellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, carboxylmethylcellulose, and related cellulosic compounds. Surprisingly we have found that the introduction of PEO brings a paste in an already low wall drag (LWD) state to even an even lower low wall drag state while increasing the tensile properties of the batch.

[0043] We have found that such substitution is particularly effective when the cellulosic binder comprises a methylcellulose constituent. In embodiments, the ratio of the amounts (in wt% with respect to the inorganic component) of the methylcellulose constituent to the polyethylene oxide is between 0.75: 1 and 1.25: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.80: 1 and 1.20: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.90: 1 and 1.10: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.95: 1 and 1.05: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is about 1 : 1. In embodiments, the batch mixture comprises methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles. In embodiments, the cellulosic binder component is methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles.

[0044] A measure of tensile strength is strain at break (“SAB” or “SAB%) as measured by capillary rheometer tensile test.

[0045] In one aspect, ceramic precursor batch mixtures, or ceramic-forming pastes or ceramic pastes, are disclosed herein, comprising an inorganic component comprised of inorganic particles, a cellulosic binder component, a lubricant component comprised of fatty acid and/or synthetic oil, a liquid vehicle component comprised of water, and polyethylene oxide. In embodiments, a ratio of the amounts (in wt% with respect to the inorganic component) of the cellulosic binder component to the polyethylene oxide is between 0.5: 1 and 1.5: 1. In embodiments, the cellulosic binder component comprises a methylcellulose constituent comprised of one or more of methylcellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, carboxylmethyl cellulose, and related cellulosic compounds. [0046] In embodiments, the cellulosic binder component consists of a methylcellulose constituent. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.75: 1 and 1.25: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.80: 1 and 1.20: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.90: 1 and 1.10: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.95: 1 and 1.05: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is about 1 : 1. In embodiments, the batch mixture comprises methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic component. In embodiments, the cellulosic binder component is methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic component.

[0047] In embodiments, the cellulosic binder component consists of methylcellulose. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose to the polyethylene oxide is between 0.75: 1 and 1.25: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose to the polyethylene oxide is between 0.80: 1 and 1.20: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose to the polyethylene oxide is between 0.90: 1 and 1.10: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose to the polyethylene oxide is between 0.95: 1 and 1.05: 1. In embodiments, the ratio of the amounts (in wt%) of the methylcellulose to the polyethylene oxide is about 1 : 1. In embodiments, the resulting batch mixture is in a lower wall drag state than the starting low wall drag batch mixture.

[0048] In embodiments, the PEO constituent has a molecular weight of 1 million or more. In embodiments, the PEO constituent has a molecular weight of 1-2 million. In embodiments, the PEO constituent has a molecular weight of 2 million or more. In embodiments, the PEO constituent has a molecular weight of 5 million or more. In embodiments, the PEO constituent has a molecular weight of 7 million or more.

[0049] In embodiments, the PEO constituent has a molecular weight of 5 million or less. In embodiments, the PEO constituent has a molecular weight of 4 million or less. In embodiments, the PEO constituent has a molecular weight of 3 million or less. In embodiments, the PEO constituent has a molecular weight of 2 million or less. In embodiments, the PEO constituent has a molecular weight of 1-2 million. In embodiments, the PEO constituent has a molecular weight of 1-3 million. In embodiments, the PEO constituent has a molecular weight of 1-4 million.

[0050] In embodiments, the oil constituent comprises a synthetic oil. In embodiments, the synthetic oil comprises a polyalphaolefin.

[0051] In embodiments, the inorganic particles are comprised of cordierite precursors. [0052] In embodiments, the batch mixture comprises methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles.

[0053] In another aspect, methods disclosed herein comprise adjusting a paste composition of a starting low wall drag ceramic and/or ceramic-forming paste or batch mixture (“starting batch mixture”), the mixture comprising an inorganic component comprised of inorganic particles, a cellulosic binder component, a lubricant component comprised of fatty acid and/or synthetic oil, and a liquid vehicle component comprised of water, the method comprising adding PEO, or increasing the amount of PEO, to the low wall drag mixture on a weight % basis with respect to the inorganic particles, and reducing the amount of the cellulosic binder component on a weight % basis with respect to the inorganic particles, such that the resulting batch mixture is in a low wall drag state.

EXAMPLES

[0054] Embodiments will be further understood by the following non-limiting examples.

[0055] FIG. 1 shows a batch mixture composition adjustment such that in a modified/adjusted composition, PEO replaced a portion of the methylcellulose (Methocel), which enable a reduction in the amount of lubricant in a cordierite-forming mixture.

[0056] FIG. 2 graphically illustrates capillary rheometer measurements (wall shear stress Tw plotted versus Rate of extrusion, for 3 separate paste temperature conditions: 20 °C, 30 °C, and 40 °C) of paste of the modified composition of FIG. 1 having 1% PEO by weight of inorganics vs. the unmodified starting composition having 0% PEO (and starting or standard lubricant package), including best fit curves for each. FIG. 2 shows similar wall drag vs velocity of the unmodified paste with standard lubricant versus the modified composition of FIG. 1 having 1% PEO.

[0057] FIG. 3 graphically illustrates capillary rheometer measurements (die pressure Pdie plotted versus Penetrometer reading, for the modified composition of FIG. 1 having 1% PEO by weight of inorganics vs. the unmodified starting composition having 0% PEO (and starting or standard lubricant package), including best fit curves for each. The 1% PEO composition of FIG. 1 exhibits lower die pressure at stiffness compared to the 0% PEO composition.

[0058] FIG. 4 graphically illustrates capillary rheometer measurements (wall shear stress Ty plotted versus Strain at Break (SAB) for the modified composition of FIG. 1 having 1% PEO by weight of inorganics vs. the unmodified starting composition having 0% PEO (and starting or standard lubricant package), that is FIG. 4 shows stiffness vs Strain at Break (SAB%) from tensile test, wherein the 1% PEO composition of FIG. 1 exhibits significant SAB improvement over the paste composition without PEO (0% PEO).

[0059] FIG. 5 graphically illustrates extrusion pressure in a twin screw extruder comparing the 0% PEO paste and the 1% PEO paste of FIG. 1, where both compositions exhibited similar pressure stability.

[0060] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A ceramic-forming batch mixture comprising: an inorganic component comprised of inorganic particles, a cellulosic binder component, a lubricant component comprised of fatty acid and/or synthetic oil, a liquid vehicle component comprised of water, and polyethylene oxide, wherein a ratio of the amounts (in wt%) of the cellulosic binder component to the polyethylene oxide is between 0.5: 1 and 1.5: 1.

2. The batch mixture of claim 1 wherein the cellulosic binder component comprises a methylcellulose constituent comprised of one or more of methylcellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, carboxylmethyl cellulose, and related cellulosic compounds.

3. The batch mixture of claim 1 wherein the cellulosic binder component consists of a methylcellulose constituent.

4. The batch mixture of claim 3 wherein the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.75: 1 and 1.25: 1.

5. The batch mixture of claim 3 wherein the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.80: 1 and 1.20: 1.

6. The batch mixture of claim 3 wherein the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.90: 1 and 1.10: 1.

7. The batch mixture of claim 3 wherein the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is between 0.95: 1 and 1.05: 1.

8. The batch mixture of claim 3 wherein the ratio of the amounts (in wt%) of the methylcellulose constituent to the polyethylene oxide is about 1 : 1.

9. The batch mixture of claim 1 wherein the batch mixture comprises methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles.

10. The batch mixture of claim 1 wherein the cellulosic binder component is methylcellulose in an amount greater than 3.0 wt% and less than 5.40 wt% with respect to the inorganic particles.

11. The batch mixture of claim 1 wherein the batch mixture is in a low wall drag state.

12. The batch mixture of claims 1-11 wherein the PEO has a molecular weight of 1 million or more.

13. The batch mixture of claims 1-11 wherein the PEO has a molecular weight of 1-2 million.

14. The batch mixture of claims 1-11 wherein the PEO has a molecular weight of 2 million or more.

15. The batch mixture of claims 1-11 wherein the PEO has a molecular weight of 5 million or more.

16. The batch mixture of claims 1-11 wherein the PEO has a molecular weight of 7 million or more.

17. The batch mixture of claims 1-11 wherein the synthetic oil comprises a polyalphaolefin.

18. The batch mixture of claims 1-11 wherein the PEO has a molecular weight of 5 million or less.

19. The batch mixture of claims 1-11 wherein the PEO has a molecular weight of 2 million or less.

20. The batch mixture of claims 1-11 wherein the PEO has a molecular weight of 1 million or less.

21. A method of manufacturing a ceramic-forming batch mixture, the method comprising: adjusting a composition of a starting low wall drag ceramic-forming batch mixture (“starting batch mixture”), the mixture comprising an inorganic component comprised of inorganic particles, a cellulosic binder component, a lubricant component comprised of fatty acid and/or synthetic oil, and a liquid vehicle component comprised of water, adding PEO to the low wall drag mixture on a weight % basis with respect to the inorganic particles, and reducing either the amount of the cellulosic binder component on a weight % basis with respect to the inorganic particles, or the amount of the lubricant component on a weight % basis with respect to the inorganic particles, or both, such that the resulting batch mixture is in a low wall drag state.

22. The method of claim 21 wherein extrudate of the resulting batch mixture extruded through an extrusion die under extrusion conditions has a higher tensile strength than extrudate of the starting batch mixture extruded through the same extrusion die under the same extrusion conditions.

23. The method of claim 21 wherein the resulting batch mixture has a higher strain at break than the starting batch mixture under the same test conditions.

24. The method of claim 21 wherein the resulting batch mixture is in a lower wall drag state than the starting low wall drag batch mixture.

25. The method of claim 21 wherein the cellulosic binder component comprises methylcellulose.

26. The method of claim 21 wherein the cellulosic binder component consists of methylcellulose.

27. The method of claims 22-26 wherein the PEO has a molecular weight of 1 million or more.

28. The method of claims 22-26 wherein the PEO has a molecular weight of 1-2 million.

29. The method of claims 22-26 wherein the PEO has a molecular weight of 2 million or more.

30. The method of claims 22-26 wherein the PEO has a molecular weight of 5 million or more.

31. The method of claims 22-26 wherein the PEO has a molecular weight of 7 million or more.

32. The method of claims 22-26 wherein the synthetic oil comprises a polyalphaolefin.

33. The method of claims 22-26 wherein the PEO has a molecular weight of 5 million or less.

34. The method of claims 22-26 wherein the PEO has a molecular weight of 2 million or less.

35. The method of claims 22-26 wherein the PEO has a molecular weight of 1 million or less.