Batch compositions containing pre-reacted inorganic particles and methods for making green bodies therefrom - Patents.com

Abstract

A batch composition comprising pre-reacted spherical inorganic particles, a small amount of fine inorganic particles ("fines"), and a very large amount of liquid vehicle. The batch composition has a particle size of 20 μm≦D 50 ≦100μm, D 90 The present invention provides a high-speed extrusion batch composition having a high Tau / Beta ratio. The present invention provides a high-speed extrusion batch composition having a high Tau / Beta ratio. The present invention provides a high-speed extrusion batch composition having a high Tau / Beta ratio. The present invention also ...

Description

Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Patent Application No. 62 / 579,585, filed October 31, 2017, and U.S. Provisional Patent Application No. 62 / 579,579, filed October 31, 2017, the contents of which are incorporated herein by reference in their entireties. [Technical field]

[0002] SUMMARY The present disclosure relates to batch compositions including pre-reacted inorganic particles and methods for making green body articles therefrom. [Background technology]

[0003] Cordierite and aluminum titanate based porous ceramic honeycomb bodies have been used in catalytic converters and particulate filters for diesel and gasoline engine exhaust aftertreatment.

[0004] Such ceramic honeycomb bodies can be manufactured by extruding a plasticized batch composition of the inorganic and organic materials and liquid vehicle through an extrusion die of an extruder to produce a wet green honeycomb body, which can be dried and fired to produce a porous ceramic honeycomb body. Summary of the Invention

[0005] An exemplary embodiment of the present disclosure relates to a batch composition. The batch composition comprises: 20μm≦D 50 ≦50μm, D 90 ≦100 μm, and D 10 ≧5μm and pre-reacted spherical inorganic particles having a narrow particle size distribution of less than 20% by weight of fine inorganic particles by top-up addition based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm; and an LV% of 28% by weight or more by top-up addition to all inorganic particles in the batch composition; LV% is the liquid vehicle percent, and 90% of the pre-reacted inorganic particles in the particle size distribution are D 90 10% of the pre-reacted inorganic particles have a diameter of D 10 It has a diameter of D 50 is the median particle size of the particle size distribution.

[0006] In some embodiments, the pre-reacted spherical inorganic particles have a diameter of 20 μm≦D 50 ≦45 μm.

[0007] In some embodiments, the pre-reacted spherical inorganic particles have a diameter of 25 μm≦D 50 ≦45 μm.

[0008] In some embodiments, the batch composition comprises D 90 ≦75 μm.

[0009] In some embodiments, the batch composition comprises D 90 ≦65 μm.

[0010] In some embodiments, the batch composition comprises D 10 ≧10 μm.

[0011] In some embodiments, the batch composition comprises D 10 ≧25 μm.

[0012] In some embodiments, the batch composition comprises D 90 ≦75μm and D 10 ≧5 μm.

[0013] In some embodiments, the batch composition comprises D 90 ≦65μm and D 10 ≧5 μm.

[0014] In some embodiments, the batch composition comprises D 90 ≦70μm and D 10 ≧10 μm.

[0015] In some embodiments, the pre-reacted spherical inorganic particles have a dB≦2.00, B =(D 90 -D 10 ) / D 50 It is.

[0016] In some embodiments, the pre-reacted spherical inorganic particles have a dB≦1.00.

[0017] In some embodiments, the pre-reacted spherical inorganic particles have a dB≦0.90.

[0018] In some embodiments, the pre-reacted spherical inorganic particles have a dB≦0.80.

[0019] In some embodiments, the batch composition comprises less than 15% by weight fine inorganic particles having a fine particle size distribution with a median diameter of less than 5 μm.

[0020] In some embodiments, the batch composition comprises less than 10% by weight fine inorganic particles having a median diameter of less than 5 μm.

[0021] In some embodiments, the fine inorganic particles in the batch composition include fine alumina and fine silica, each having a median diameter of less than 2 μm.

[0022] In some embodiments, the fine inorganic particles in the batch composition include fine alumina and colloidal silica, each having a particle size distribution with a median diameter of less than 1 μm.

[0023] In some embodiments, the batch composition has a ratio of the total mass of the fine inorganic particles in the batch composition to the total mass of the pre-reacted spherical inorganic particles in the batch composition of from 3:97 to 20:80.

[0024] In some embodiments, the pre-reacted spherical inorganic particles have an AR≦1.2, where AR is the average aspect ratio measured across a first width having a maximum dimension and divided by a second width having a minimum dimension across the pre-reacted spherical inorganic particles.

[0025] In some embodiments, the pre-reacted spherical inorganic particles are formed by a spray drying process.

[0026] In some embodiments, the weight percent of the liquid vehicle is 30% or greater by weight via superaddition based on the total weight of all inorganic particles in the batch composition.

[0027] In some embodiments, the weight percent of the liquid vehicle is 35% or greater by weight via superaddition based on the total weight of all inorganic particles in the batch composition.

[0028] In some embodiments, the weight percent of the liquid vehicle is 40% or more by weight via superaddition based on the total weight of all inorganic particles in the batch composition.

[0029] In some embodiments, the weight percent of the liquid vehicle is 45% or greater by weight via superaddition based on the total weight of all inorganic particles in the batch composition.

[0030] In some embodiments, the weight percent of the liquid vehicle is from 28% to 50% by weight, by superaddition, based on the total weight of all inorganic particles in the batch composition.

[0031] In some embodiments, the batch composition includes a combination of starch and graphite as pore formers.

[0032] In some embodiments, the batch composition comprises a combination of pea starch as a pore former in an amount of 5% to 20% by weight by over-addition to all inorganic particles in the batch composition, and graphite as a pore former in an amount of 1% to 10% by weight by over-addition to all inorganic particles in the batch composition.

[0033] In some embodiments, the batch composition includes a spherical polymeric pore former.

[0034] In some embodiments, the batch composition comprises a lubricant in an amount of 0.5% to 2.5% by weight by superaddition relative to the weight of all inorganic particles in the batch composition.

[0035] In some embodiments, the batch composition includes an organic binder in an amount of 4.0% to 8.0% by weight based on the weight of all inorganic particles in the batch composition by superaddition.

[0036] In some embodiments, the organic binder comprises a combination of a methylcellulose binder and a hydroxymethylcellulose binder, where the methylcellulose binder is about 3.0% SAT to 6.0% SAT by weight and the hydroxymethylcellulose binder is about 1.5% SAT to 3.0% SAT by weight, where SAT is defined as the superaddition to the weight of all inorganic particles in the batch composition.

[0037] In some embodiments, the organic binder comprises only hydroxymethyl cellulose binder as the organic binder in an amount of about 4.0% SAT to 8.0% SAT by weight, where SAT is defined as the superaddition to the weight of all inorganic particles in the batch composition.

[0038] In some embodiments, the pre-reacted spherical inorganic particles comprise a predominant crystalline phase of aluminum titanate.

[0039] In some embodiments, the pre-reacted spherical inorganic particles comprise a primary crystalline phase of aluminum titanate and a secondary crystalline phase of mullite.

[0040] In some embodiments, the pre-reacted spherical inorganic particles comprise a primary crystalline phase of aluminum titanate and a secondary crystalline phase of feldspar.

[0041] In some embodiments, the pre-reacted inorganic particles comprise a first crystalline phase that is primarily a solid solution of aluminum titanate and magnesium dititanate, and a second crystalline phase that comprises cordierite.

[0042] In some embodiments, the pre-reacted spherical inorganic particles comprise a primary crystalline phase of aluminum titanate and a secondary glassy phase.

[0043] In some embodiments, the pre-reacted inorganic particles include, by weight percent on an oxide basis, 4%-10% MgO, 40%-55% Al2O3, 25%-44% TiO2, and 5-25% SiO2.

[0044] In some embodiments, the batch composition has a liquid vehicle to organic binder ratio of ≧6.4%.

[0045] Exemplary embodiments of the present disclosure also relate to a green honeycomb body comprising a batch composition according to any of the above-described embodiments.

[0046] Exemplary embodiments of the present disclosure further relate to a method of manufacturing a honeycomb body, the method comprising: 20μm≦D 50 ≦50μm, D 90 ≦100 μm, and D 10 ≧5μm and pre-reacted spherical inorganic particles having a particle size distribution of less than 20% by weight of fine inorganic particles by top-up addition based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm; and LV% of 28% by weight or more by top-up addition to all inorganic particles in the batch composition, 90% of the pre-reacted spherical inorganic particles were D 90 10% of the pre-reacted spherical inorganic particles have a diameter of less than D 10 has a diameter less than D 50 is the median particle size.

[0047] The method further includes forming the batch composition into a wet green honeycomb body by extrusion, wherein the batch composition has a TauY / Beta≧2.0, where TauY is a measure of batch stiffness and Beta is the coefficient of friction of the batch composition.

[0048] In some embodiments, tauY / beta > 3.0.

[0049] In some embodiments, tauY / beta > 4.0.

[0050] In some embodiments, tauY / beta > 5.0.

[0051] In some embodiments, tauY / beta > 6.0.

[0052] In some embodiments, tauY / beta > 7.0.

[0053] In some embodiments, tauY / beta > 8.0.

[0054] In some embodiments, tauY / beta > 10.0.

[0055] In some embodiments, the molding step includes extrusion, and the T during extrusion is equal to or greater than 47° C.onset has.

[0056] In some embodiments, the method includes a T during extrusion of 50° C. or greater. onset has.

[0057] In some embodiments, the method includes a T during extrusion of 55° C. or greater. onset has.

[0058] In some embodiments, the method includes drying the wet green honeycomb body to form a dried green honeycomb body, and firing the dried green honeycomb body to form a porous ceramic honeycomb body.

[0059] An exemplary embodiment of the present disclosure also relates to a method for manufacturing a honeycomb body. The method includes mixing a batch composition including pre-reacted spherical inorganic particles and fine inorganic particles with a top-addition of less than 20% by weight based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm, and a top-addition LV% of 28% by weight or more based on all inorganic particles in the batch composition. The method further includes forming the batch composition into a wet green honeycomb body by extrusion, the batch composition having a TauY / Beta≧2.0, where TauY is a measure of batch stiffness and Beta is the coefficient of friction of the batch composition.

[0060] Exemplary embodiments of the present disclosure further relate to another batch composition, comprising: 20μm≦D 50 ≦50μm, D 90 ≦100 μm, and D 10 ≧5μm and pre-reacted spherical inorganic particles having a narrow particle size distribution of less than 20% by weight of fine inorganic particles by top-up addition based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm; LV% of 28% by weight or more by top-up addition to all inorganic particles in the batch composition; and having tauY / beta≧2.0; LV% is the liquid vehicle percent, and 90% of the pre-reacted inorganic particles in the particle size distribution are D 90 10% of the pre-reacted inorganic particles have a diameter of D 10 It has a diameter of D 50 is the median particle size of the particle size distribution, TauY is a measure of the batch stiffness, and Beta is the coefficient of friction of the batch composition.

[0061] Additional features of the present disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the present disclosure. [Brief description of the drawings]

[0062] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate example embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. [Figure 1] 1 is an isometric view of a porous ceramic honeycomb body produced from a batch composition and embodied as a particulate filter according to one or more embodiments. [Diagram 2] FIG. 2 is a graphic representation of pre-reacted spherical inorganic particles (shown distorted for illustrative purposes) used in a batch composition according to one or more embodiments. [Figure 3A] 2 is a plot of particle size distribution of several embodiments of pre-reacted spherical inorganic particles used in a batch composition according to one or more embodiments. [Figure 3B] 2 is a plot of particle size distribution of several embodiments of pre-reacted spherical inorganic particles used in a batch composition according to one or more embodiments. [Figure 4A]1 is a schematic diagram of an extruder used to form a wet green honeycomb body from a batch composition according to an embodiment. [Figure 4B] 1 is an isometric view of a dried green honeycomb body produced from a batch composition according to one or more embodiments. [Diagram 5] 1 is a flow chart of a method of manufacturing a honeycomb body according to one or more embodiments. [Figure 6] 1 is a flow chart of a method of manufacturing a honeycomb body using a batch composition according to one or more embodiments. [Figure 7] A plot of LV% (moisture in mass%) versus batch stiffness TauY for a conventional batch composition compared to various embodiments of a batch composition comprising pre-reacted spherical inorganic particles according to one or more embodiments. [Figure 8] A plot of LV% (moisture in mass%) versus batch friction beta for a conventional batch composition compared to various embodiments of a batch composition comprising pre-reacted spherical inorganic particles according to one or more embodiments. [Figure 9] FIG. 2 is a cross-sectional side view of a capillary rheometer configured to test the rheological properties of a batch composition according to an embodiment. [Figure 10] 1 is a plot of inlet pressure Pe (psi) versus velocity (inches / second) for example embodiments of batch compositions including pre-reacted spherical inorganic particles. [Figure 11] 1 is a plot of Ptotal (psi) versus sample number for example embodiments of batch compositions including pre-reacted spherical inorganic particles at multiple velocities V and different capillary lengths L. [Figure 12] 1 is a plot of Ptotal (psi) versus V (inches / second) for example embodiments of batch compositions including pre-reacted spherical inorganic particles extruded through a capillary rheometer with different capillary lengths L. [Figure 13] A plot of LV% (moisture by weight) vs. TauY / Beta for reactive batch compositions compared to LV% vs. TauY / Beta for various embodiments of batch compositions comprising pre-reacted spherical inorganic particles. [Figure 14] 4 is a plot of tauY versus beta for various embodiments of a reactive batch composition and a batch composition comprising pre-reacted spherical inorganic particles. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0063] Hereinafter, embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. However, the present disclosure can be embodied in many different forms and should not be construed as being limited to the embodiments described herein. These disclosed embodiments are provided so that this disclosure will be thorough and complete. In the drawings, sizes and relative sizes may not be drawn to scale. Like reference numbers in the drawings are used throughout the present disclosure to represent like elements.

[0064] There has been considerable effort in the honeycomb extrusion field to increase the feed rate of plasticized batch composition through the extrusion die, since the feed rate is said to be at least in part tied to the cost of the final honeycomb body. Thus, increased feed rate equates to lower production costs for the final ceramic honeycomb body. However, for several reasons, such progress has been difficult to achieve.

[0065] In the manufacture of ceramic honeycomb articles, a plasticized batch composition, which may be considered a non-ideal mixture, is extruded through an extruder equipped with an extrusion die having an array of narrow intersecting slots. A dry batch composition of inorganic components (e.g., alumina, silica, titania, and / or magnesia sources) is combined with an organic binder, a liquid vehicle (LV), optionally an oil lubricant, and optional pore former(s) and plasticized by mixing and / or kneading to produce a plasticized batch. The plasticized batch is then fed into an extruder, such as a twin-screw extruder. As used herein, "plasticized" refers to the property of a batch mixture that includes LV (e.g., deionized water) and optionally a lubricant, and that has been mixed and / or kneaded to have a paste consistency suitable for extrusion. As used herein, "batch composition" refers to a mixture of materials that includes at least inorganic raw materials, an organic binder, optional pore former(s), and LV. The plasticized batch composition may be configured as bags of material that are fed intermittently to the extruder, or as a continuous or semi-continuous feed of the plasticized batch composition that has been mixed and / or kneaded and is of a form and consistency that allows it to be fed continuously or semi-continuously to the extruder.

[0066] The plasticized batch composition can flow under pressure through one or more extruder screws (e.g., a twin screw extruder) or other suitable equipment through a narrow slot in an extrusion die of the extruder to form a green body, such as a wet green body honeycomb. The wet green honeycomb body can be dried by any suitable method, such as by using microwave drying, radio frequency (RF) drying, oven drying, or a combination thereof, to form a dried green honeycomb body. After drying, the dried green body honeycomb is fired at high temperatures in a kiln or furnace to produce a porous ceramic body, such as a porous ceramic honeycomb body.

[0067] The goal is to extrude the plasticized batch at the fastest possible feed rate while also providing a good quality wet green honeycomb body that exhibits little deformation, little tearing, and meets the desired overall geometric profile, as well as the desired shape of the cross walls and cells. Conventional batch composition production involves mixing and / or kneading raw inorganic powders of various compositions, each of which has a fairly wide particle size distribution, with a quantity of organic binder (e.g., cellulose-based binder), oil lubricant, LV such as water, and optional pore formers. Sources of inorganic powders include raw powder materials, including sources of alumina, silica, magnesia, titania, and / or the like, each of which has its own specific particle size distribution, depending on the ceramic composition to be produced. Furthermore, these particles tend to be irregular in shape and vary widely in size due to processing (e.g., coarse or fine grinding) or their natural shape (e.g., clay simplicity). The batch composition may include sintering aids such as powder sources of strontium, calcium, or other components in conventional batches to promote sintering at lower temperatures, but in such prior art conventional batch compositions, the feasible feed rate of the plasticized batch through the extrusion die has been limited by the nature of the batch composition.

[0068] For example, batch stiffness and friction between irregularly shaped batch materials with wide particle distribution and the metal wall surface of the narrow intersecting die slot of the extrusion die can limit the achievable feed rate. To some extent, batch stiffness can be adjusted by changing the relative amount of LV (e.g., water) in the plasticized batch, but if the LV% is too high, such conventional batches can have poor shape control. As used herein, moisture is expressed as LV% SAT, where SAT means the top-up addition based on the total mass of all inorganics in the batch composition.

[0069] For example, conventional prior art reactive batch compositions have been adjusted by a few LV% in water to adjust extrusion while still retaining good geometric properties of the extruded wet green body. The water percentage of conventional prior art reactive batch compositions was up to about 25 LV% in conventional reactive batch compositions (see Figures 7 and 8). The water in the reactive batch composition is adjusted by the addition of starch levels in the batch composition. Low porosity ceramic articles can be produced without starch or at very low starch levels, and only about 13% water would be used, while the same batch composition with a high starch level would use up to about 25% water for the production of high porosity honeycombs. However, if the water percentage in such conventional batch compositions is too high, it can lead to certain problems in the wet green honeycomb body, especially in the thin walls, such as slugging or slumping (loss of geometric outline) and possibly severe structural deformation, wall tearing or breakage, failure to fully bind the material flow from the slots, due to lack of proper viscosity during and after extrusion. Furthermore, such dried green honeycomb bodies resulting from such batches may shrink excessively during drying, resulting in loss of the desired overall geometric shape. Such problems may be encountered in conventional batch compositions where the LV% in the batch composition is greater than 25% due to top-up additions based on the total mass of inorganic particles in the batch composition.

[0070] Furthermore, as the feed rate is increased, the temperature of the plasticized batch composition being extruded through the narrow slot increases due to shear deformation. At low levels of shear, the extrusion pressure remains approximately constant. However, above a threshold feed rate, the batch will no longer be able to handle the increased temperature and will therefore harden, resulting in a significant increase in extrusion pressure. Such hardening can lead to die failure due to extremely high pressures or simply due to an inability to extrude above the threshold feed rate, i.e., no material is extruded.

[0071] This behavior is attributed to the thermal phase transition of the cellulose-based organic binder contained in the plasticized batch composition. At higher temperatures, cellulose molecules lose water from their pendant methoxy groups, resulting in hydrophobic association between adjacent chains, which results in phase separation and gel formation. N. Sakar, J. Appl. Polymer Science 24, 1073 (1979); “Thermal gelation properties of methyl- and hydroxypropyl methylcellulose.” The stiffness of the plasticized batch composition increases as gelation progresses, and as a result, a significant increase in extrusion pressure is observed at the onset of gelation. The onset of gelation is characterized by a fairly sharp inflection (change in slope) of the temperature vs. pressure curve, T onset The temperature at which gelation occurs, i.e., T onset is one measure of how fast this batch will be extruded.

[0072] The present inventors have recognized that certain conventional batch compositions, such as conventional aluminum titanate (AT) batch compositions, exhibit a significant increase in pressure in their pressure-temperature curves near 35-40° C. The T onsetis dependent on the type and level of methocel, the LV% present in the plasticized batch, and the batch composition. Notably, it is desirable to use a relatively stiff batch (having a high Tau Y) since this can result in better shape control of the wet green honeycomb body, i.e., less wall and / or cell deformation, less tearing, and less slumping (geometric deformation as a result of mass). The stiffness factor "Tau Y" is a measure of the stiffness of a particular plasticized batch composition. A stiffer batch leads to higher extrusion pressures and lower feed rates. The addition of a liquid vehicle (e.g., water) to a conventional batch composition can allow for improved feed rates due to a lower coefficient of friction (beta) between the batch and the narrow die slot, but generally at the expense of shape control of the wet and dry green honeycomb bodies. The coefficient of friction "beta" is a measure of the friction of the plasticized batch composition through a slot of a defined size.

[0073] Thus, in conventional batch compositions, there is a natural trade-off between desirable high batch stiffness (high Tau-Y) and low wall friction (low Beta). Thus, the ratio of the batch stiffness coefficient (Tau-Y) to the coefficient of friction (Beta) (Tau-Y / Beta) can be used to characterize the batch behavior during extrusion. It is believed that a high Tau-Y / Beta ratio is desirable, as this allows for higher extrusion rates. However, the Tau-Y / Beta ratios of conventional batches that are desirable for extrusion are very low, i.e., in the range of about 1.0-1.5.

[0074] Therefore, improvements in batch composition that allow for higher feed rates while also retaining shape control and quality of wet and dry green honeycombs would be considered a major advancement in honeycomb extrusion technology.

[0075] In view of the above-mentioned limitations of conventional batches, one or more embodiments of the present disclosure provide batch compositions that can enable high extrusion rates, and in some cases extrusion rates that significantly exceed the best conventional feed rates, while also providing excellent shape control of the extruded object. For example, one or more batch compositions can enable a dramatic increase in feed rate during extrusion of wet green body honeycomb. Furthermore, one or more of the batch compositions can provide a relatively large process window based on the rheology of the batch composition. Such a relatively large (enlarged) process window includes an expanded range of extrusion pressures, extrusion temperatures, and extrusion speeds.

[0076] One or more embodiments of the present disclosure include a batch composition that includes a combination of relatively coarse, pre-reacted, spherical inorganic particles with a controlled narrow particle size distribution associated with a very high LV% in the batch composition, and a relatively small amount of fine inorganic particles (hereinafter "fines") in the batch mineral. The fines in the batch composition are expressed as weight % SAP, where "SAP" means by over-addition to the total amount of pre-reacted spherical inorganic particles in the batch composition. The liquid vehicle (LV) in the batch composition is added in weight % SAT, where SAT means by over-addition to the total mass of the batch mineral (mass of pre-reacted spherical inorganic particles plus "fines"). The addition of other components of the batch composition, such as the addition of organic binders, lubricants, and optional pore formers, are all based on weight % SAT.

[0077] The formulas for SAP and SAT are as shown in Equations 1 to 5 below: Mass% fines in SAP = (mass of fines / mass of PISP) ​​x 100 Equation 1 LV% SAT = [LV mass / (PISP mass + fines mass)] × 100 Equation 2 Mass % of organic binder SAT = [mass of OB / (mass of PISP + mass of fine particles] × 100 Equation 3 Lubricant mass% SAT = (lubricant mass / PISP mass + fines mass) x 100 Equation 4 Mass % of pore former SAT = [mass of PF / (mass of PISP + mass of fines] × 100 Equation 5 During the ceremony: PISP = pre-reacted spherical inorganic particles; OB=organic binder, and PF=pore former.

[0078] Applications of the porous ceramic honeycomb bodies manufactured from the batch compositions described herein may include, for example, the porous ceramic honeycomb bodies incorporated into diesel catalyst supports, gasoline catalyst supports, and / or diesel and gasoline particulate filters. In particular, the porous ceramic honeycombs may be used in automotive exhaust gas treatment, including catalyzed substrates for carbon monoxide (CO) conversion, particulate filters for reducing diesel and gasoline particulate emissions, and catalyzed coated particulate filters for selective catalytic reduction of nitrogen oxides (NOx). The resulting porous ceramic bodies may also be used in other filtration and / or catalyst support applications, such as porous filter membranes, CO2 capture devices, chemical flow reactors, chemical absorption devices, molten metal filters, regenerator cores, trough filters, candle filters, disk filters, radial flow filters, and the like. One particularly useful example is a porous ceramic honeycomb article 100 embodied in the form of a particulate filter as shown in FIG. 1.

[0079] The porous ceramic honeycomb article 100 includes a porous ceramic honeycomb body 101 including a matrix of intersecting walls 102 forming channels 104, 106 extending from a first end 108 to a second end 110. In the particulate filter embodiment shown, some of the channels 104, 106 may be blocked with plugs (e.g., plug 112) as known in the art. In other embodiments, for example, plugs may not be provided and the porous ceramic honeycomb body 101 may be configured in a flow-through configuration or may be used as a catalyst support.

[0080] Further details, features, and example embodiments of the batch compositions, their performance, green bodies (such as wet and dry green honeycomb bodies) and porous ceramic bodies (such as porous ceramic honeycomb bodies) produced from the batch compositions, and methods of manufacturing green body honeycomb and porous ceramic articles from the batch compositions, as well as other aspects, will now be described with reference to the various tables and Figures 1A-14 described herein.

[0081] D 50 In the batch composition, the relatively coarse, pre-reacted, spherical inorganic particles are 20 μm≦D 50 ≦50 μm (including 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, and 50 μm), where D 50 is defined herein as the median particle diameter of the particle size distribution. In some embodiments, the relatively coarse, pre-reacted, spherical inorganic particles have a diameter of about 100 nm, as further described herein. 50 For example, in some embodiments, the median particle size of the pre-reacted spherical inorganic particles is in the range of 20 μm≦D 50 ≦45μm, or even 25μm≦D 50 The median particle size of the pre-reacted spherical inorganic particles can be adjusted by varying the solid loading and / or by varying processing parameters such as the spray drying pressure of the fountain nozzle or the rotation speed of the atomizer nozzle of the spray dryer, the nozzle size, or the temperature setting of the spray dryer or the type and amount of organic or polymeric binder added when producing green spherical inorganic particles that are calcined or fired to produce the pre-reacted spherical inorganic particles.

[0082] D 90 Further, the pre-reacted spherical inorganic particles may, in some embodiments, be 90 ≦100μm, D 90 ≦75μm, or even D 90The particle size distribution may include a large proportion of particles below a particular diameter, such as ≦60 μm. 90 is defined herein as the particular coarse particle diameter of the pre-reacted spherical inorganic particles within a particle size distribution, where 90% of the pre-reacted spherical inorganic particles within this distribution have a diameter equal to or less than the coarse diameter, i.e., the remaining particles (approximately 9.9999%) have a larger diameter.

[0083] D 10 Furthermore, the pre-reacted spherical inorganic particles may, in some embodiments, be 10 ≧5μm, D 10 ≧10μm, D 10 ≧15μm, D 10 ≧20μm, or even D 10 The particle size distribution may include a fine fraction of particles larger than a certain size, such as ≧25 μm. 10 is defined herein as the particular fine diameter of a particle within a particle size distribution, where 10% of the pre-reacted spherical inorganic particles in the particle size distribution have a particle diameter equal to or less than the fine diameter, i.e., the remainder (approximately 89.9999%) have a larger diameter.

[0084] Further, in some embodiments, the pre-reacted spherical inorganic particles are 90 ≦75μm and D 10 ≧5μm, D 90 ≦65μm and D 10 ≧5μm, or even D 90 ≦70μm and D 10 It may have a relatively narrow particle size distribution, defined as having a combination of > 10 μm.

[0085] dB In some embodiments, the relatively coarse pre-reacted spherical inorganic particles may have a relatively narrow particle size distribution in terms of its width. The relative narrowness of the particle size distribution of the pre-reacted spherical inorganic particles may be measured in terms of the width factor dB, where the width factor dB is defined by Equation 6 as follows: dB = (D90 -D 10 ) / D 50 formula 6 For example, the breadth factor dB of the particle size distribution according to embodiments can be defined in some particularly narrow embodiments by dB≦2.00, or even dB≦1.00, or even dB≦0.90, or even dB≦0.80.

[0086] As will be appreciated, the pre-reacted spherical inorganic particles have a particle size distribution that can be designed and / or engineered to meet the pore size distribution parameters described above. The particle sizes described herein are measured using a Microtrac S3500 laser diffractometer.

[0087] In some embodiments, the narrowness of the relatively coarse pre-reacted spherical inorganic particles can be improved by a specific process adapted to remove some of the fine fraction of the pre-reacted particles therein. For example, processes such as sieving, cyclone separation, air classification, separation by sedimentation or settling, or the like, may be used to remove some of the coarse and / or fine fractions from the particle size distribution. For example, the coarse part of the particle size distribution having a size larger than about 60 μm can be removed by passing the powder through a sieve of about 270 mesh (having a mesh opening of about 53 μm), thus removing particles having a size smaller than 53 μm. Other sieve sizes can be used to remove other fractions from the larger end of the particle size distribution. Fine fractions can also be removed by constructing a sieve with a finer mesh and discarding the particles that pass through this mesh.

[0088] fine grain Moreover, the batch composition contains a small proportion of fine inorganic particles ("fines"). In particular, the batch composition contains less than 20% SAP by weight of fine inorganic particles. Fine inorganic particles (fines) are relatively small particles with a particle distribution of "fines" added to the batch composition having a median particle size of less than 5 μm. As used herein, "SAP" refers to a top-up addition based on the total mass of pre-reacted spherical inorganic particles contained in the batch composition. In other embodiments, the batch composition contains less than 15% SAP by weight of fine inorganic particles, in which the distribution of fine particles has a median particle size of less than 5 μm, less than 10% SAP by weight of fine inorganic particles, in which the distribution of fine particles has a median diameter of less than 5 μm, or even less than 7.5% SAP by weight of fine inorganic particles, in which the distribution of fine particles has a median diameter of less than 5 μm.

[0089] In some embodiments, the "fines" in the batch composition consist essentially of a combination of fine alumina and fine silica. In yet another embodiment, both the fine alumina particles and the fine silica particles added to the batch composition each have a distribution with a median particle size of less than 2 μm. In some embodiments, the batch composition includes a combination of fine alumina and colloidal silica, where each has a particle distribution with a median particle size of less than 1 μm.

[0090] In some embodiments, the finely divided inorganic particles ("fines") in the batch composition may include a combination of alumina, talc, silica, and ceria particles, each having a median diameter of less than 5 μm.

[0091] In some embodiments, the batch composition may include fine titania having a particle distribution with a median particle size of less than 1 μm. In other embodiments, the fine inorganic particles in the batch composition may include a combination of alumina particles, talc particles, silica particles, and titania particles, each having a median diameter of less than 5 μm. The addition of titania particles can be used as a modulator that allows the adjustment of the rheological behavior of the batch composition by adding various levels of Ti.

[0092] The fine inorganics in the batch composition function as inorganic binders that bind the pre-reacted spherical inorganic particles together. Fine inorganic oxide powders have a large surface area per mass, and because of their relatively large surface area, they interact strongly with the batch LV (e.g., water). Most oxides are hydrophilic and therefore tend to "bind" a lot of water, thereby reducing the mobility of the batch water and inorganic particles. Thus, the result is thickening of the batch composition and increasing friction in the batch. Higher internal batch friction means higher friction of the batch composition through the extrusion die. Higher pressures forcing the batch composition through the extrusion die contribute to lower extrusion rates. Thus, the inventors have found that a small amount of fines combined with the use of pre-reacted particles and high moisture is desirable to achieve high extrusion rates.

[0093] In yet another embodiment, the batch composition comprises more than 3% and less than 15% by weight of fine inorganic particles, the fine inorganic particles having a distribution of less than 5 μm in median size. In another embodiment, the batch composition comprises more than 3% and less than 10% by weight of fine inorganic particles, the fine inorganic particles having a distribution of less than 5 μm in median size. In some embodiments, the batch composition comprises more than 3% and less than 7.5% by weight of fine inorganic particles, the fine inorganic particles having a distribution of less than 5 μm in median size. In another embodiment, the batch composition comprises more than 5% and less than 7% by weight of fine inorganic particles, the fine inorganic particles having a distribution of less than 5 μm in median size.

[0094] In some embodiments, the fine particles in the batch composition include about 1% to 5% by weight of alumina particles, 1% to 7% by weight of talc particles, and 0.5% to 3% by weight of silica particles. In some embodiments, the fine inorganic particles may include very fine alumina particles having a particle distribution with a median particle size of less than about 1 μm, or even less than 0.7 μm. In some embodiments, the fine inorganic particles may include fine talc particles having a particle distribution with a median particle size of less than about 5 μm. In some embodiments, the fine inorganic particles may include fine silica particles having a particle distribution with a mean diameter of less than about 0.5 μm, or even less than 0.1 μm. The fine silica particles may be colloidal silica and may be provided as a suspension in water (e.g., a 40% suspension in water).

[0095] When alumina, talc and silica are used in combination as the inorganic binder, the composition is targeted to produce some glass phase in the regions between the cordierite and the pre-reacted spherical inorganic particles upon firing. Low levels of glass formers such as ceria, yttria, calcia, other alkaline earths, rare earths or alkalis at levels of less than 0.5% SAP, less than 0.3% SAP or even less than 1% SAP can be added to promote glass formation.

[0096] When alumina and talc alone are used in combination as the inorganic binder, the composition is targeted to produce, upon firing, mullite, cordierite, and a glass phase in the regions between the pre-reacted spherical inorganic particles.

[0097] When alumina, talc, silica, and titania are used in combination as inorganic binders, the composition is targeted to produce cordierite, aluminum titanate, and some glass phase in the regions between the pre-reacted spherical inorganic particles upon firing. However, as discovered by the present inventors, even small amounts of titania in the batch composition can produce a very viscous slip layer and dramatically reduce the tau-Y / beta ratio to near that of conventional batches. Therefore, as a design for high extrusion rates, the batch composition may be substantially free of titania. However, as mentioned above, smaller amounts may be used as a lever to control the rheology of the batch composition.

[0098] In some embodiments, the batch composition has a ratio of the total mass of fine inorganic particles in the batch composition to the total mass of pre-reacted spherical inorganic particles in the batch composition (RFP), where RFT (defined as the ratio of fines to pre-reacted) is defined by the following Equation 7: RFT = mass of fines / mass of PISP Equation 7 In an embodiment, the ratio RFP may be from 3:97 to 20:80.

[0099] Aspect Ratio In some embodiments, the pre-reacted spherical inorganic particles in the particle size distribution of the batch composition may, on average, have a spherical or nearly spherical shape and may have an aspect ratio (AR) of AR≦1.2, as shown in FIG. 2, where AR is the average aspect ratio across all pre-reacted spherical inorganic particles in the batch composition, and the AR of each pre-reacted spherical inorganic particle is measured across a first width (W1) having a maximum dimension and divided by a second width (W2) having a minimum dimension across the pre-reacted spherical inorganic particle 203. To achieve this AR≦1.2, the pre-reacted spherical inorganic particles 203 may be formed by a spray drying process, for example, as described in detail in WO 2016 / 138192. In some embodiments, the pre-reacted spherical inorganic particles 203 are rotary calcined at an appropriate temperature to maintain a spherical shape.

[0100] Examples of specific pre-reacted spherical inorganic particles 203 are shown below in Table 1. Figures 3A and 3B show plotted examples of representative particle size distributions of spray-dried and pre-reacted spherical inorganic particles.

[0101] [Table 1]

[0102] Three representative particle size distribution examples of the relatively coarse, pre-reacted, spherical inorganic particles are shown in FIG. 3A. For the relatively coarse, pre-reacted, spherical inorganic particles used in the example batch compositions, D 50 , D 90 , D 10 , D 95 Further data such as D5 and dB are shown in Table 1 above. In particular, FIG. 3A shows the median particle size D of about 20 μm to about 30 μm. 50 FIG. 3B shows a relatively narrow pre-reacted particle size distribution with a D of about 42 μm. 50 1 shows an example of a pre-reacted particle size distribution having a relatively coarser distribution having 50Other values ​​of the median particle diameter D may be obtained by adjusting the particle diameter by spray drying during the formation of the green inorganic particle spheroids, as described above. In addition, or optionally, the desired median particle diameter D 50 20μm ≧ D 50 Sieving or other post-formation processing may be used to adjust the particle size to ≧50 μm. In the above example, the phase composition of the pre-reacted spherical inorganic particles includes cordierite, mullite, and aluminum titanate (CMAT), with a primary phase of a solid solution of aluminum titanate with magnesium dititanate, a second phase of cordierite, some mullite, and possibly a glass phase. However, as will become apparent, other phase compositions of the pre-reacted spherical inorganic particles may be produced.

[0103] Level% According to another aspect, the liquid vehicle percentage (LV%) in the batch composition is significantly higher than that used in conventional batches, while still maintaining a very suitably high batch stiffness. The liquid vehicle LV provides a medium in which the organic binder dissolves, thus providing plasticity to the batch composition and achieving wetting of the inorganic particulates therein. The LV can be an aqueous-based liquid, which is usually water or a water-miscible solvent. In one implementation, the LV is deionized water, but other solvents such as alcohol can also be used. The liquid vehicle percentage LV% of the batch composition is LV%≧28% by mass, or even LV%≧30%, LV%≧35%, or even LV%≧40%, or even LV%≧45% superaddition (SAT) based on the total mass of inorganic particles present in the batch composition (e.g., pre-reacted spherical inorganic particles plus "fines") In some embodiments, the LV% may include 28%≦LV%≦50% superaddition (SAT) by mass. Remarkably, as discovered by the inventors herein, wet green honeycomb bodies 446W (FIG. 4A) formed from batch compositions disclosed herein having even such extremely high liquid vehicle percentages (LV%≧28%) have very low wall resistance, as seen by the low beta, but also remarkably very high batch stiffness such that excellent shape control is maintained, as seen by the relatively high tau-Y. Notably, a high ratio of tau-Y / beta is also achieved with this batch composition.

[0104] Pore ​​formers In some embodiments, one or more pore formers may be included in the batch composition. Pore formers are particulate organic materials included in the batch composition that burn out during firing to generate interconnected open pores within the fired ceramic article (e.g., within a porous ceramic honeycomb body). In particular, the pore formers may include a single pore former material or a combination of pore former materials.

[0105] In some embodiments, the one or more pore formers may include starch, graphite, or polymers (e.g., polymer beads). In one particularly effective embodiment, the one or more pore formers include starch, such as pea starch. In embodiments including only starch as the organic pore former, the starch may be provided in an amount of about 5% SAT to 30% SAT by weight. Other suitable starches that may be used as pore formers in the batch composition include potato starch, corn starch, sago starch, and pea starch. The starch can be, for example, a standard starch, a cross-linked starch, or a highly cross-linked starch.

[0106] In other embodiments, the batch composition includes a combination of pore formers, such as a combination of starch and graphite as pore formers. For example, in some embodiments, the batch composition includes a combination of pea starch as a pore former in an amount of 5% to 30% by weight SAT relative to all inorganic particles (pre-reacted spherical inorganic particles and "fines") in the batch composition, and graphite as a pore former in an amount of 1% to 15% by weight SAT relative to all inorganic particles in the batch composition. The pea starch as a pore former may be a very highly crosslinked (vhxl) pea starch as listed in Table 3 below. For example, vhxl pea starch has a median particle size of about d 50 = 26 μm. The graphite listed in Table 3 may be platelet graphite, having plates with a median particle size of about 100 μm in diameter and about 10 μm in height, with a very broad particle size distribution.

[0107] In another example embodiment, the batch composition includes a spherical polymeric pore former. The spherical polymeric pore former may have a median particle size of, for example, 15 μm to 40 μm.

[0108] Organic Binder The batch composition may include an organic binder. The organic binder may be, for example, a hydrophobically modified cellulose ether binder. In some embodiments, the hydrophobically modified cellulose ether binder may be, but is not limited to, methylcellulose, ethyl hydroxyethyl cellulose, hydroxybutyl methylcellulose, hydroxymethylcellulose, hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, hydroxybutyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethylcellulose, mixtures thereof, and the like. Methylcellulose derivatives and / or methylcellulose derivatives are particularly suitable for use as organic binders in batch compositions in which methylcellulose and hydroxypropyl methylcellulose are used. A source of cellulose ethers is METHOCEL™ cellulose products available from DOW Chemical Co.

[0109] Some embodiments of the batch composition may include a combination of methylcellulose and hydroxypropylmethylcellulose. Other combinations of cellulose ether binders may include cellulose ethers with different molecular weights. Alternatively, the combinations of cellulose ethers may include cellulose ethers with different hydrophobic groups, different concentrations of the same hydrophobic groups, or other combinations of cellulose ethers. The different hydrophobic groups may be, as non-limiting examples, hydroxyethyl or hydroxypropyl.

[0110] The organic binder may be provided in the batch composition in an amount of about 4.0% SAT to 8.0% SAT by weight. The organic binder may be a combination of methylcellulose binder and hydroxymethylcellulose binder, in some embodiments, where the methylcellulose binder is about 3.0% SAT to 6.0% SAT by weight and the hydroxymethylcellulose binder is about 1.5% SAT to 3.0% SAT by weight. Some embodiments may include only hydroxymethylcellulose binder as the organic binder, for example, in an amount of about 4.0% SAT to 8.0% SAT by weight. In some embodiments, the ratio of liquid vehicle to organic binder can be ≧6.4%.

[0111] Lubricants / Surfactants The batch composition may further include a lubricant, such as an oil lubricant. Non-limiting examples of oil lubricants include tall oil, light mineral oil, corn oil, high molecular weight polybutene, polyol esters, blends of light mineral oil and wax emulsions, blends of paraffin wax in corn oil, combinations thereof, and the like. The amount of lubricant may be from about 0.5% SAT to about 5% SAT by weight. In an exemplary embodiment, the oil lubricant may be tall oil present in the batch composition at from about 0.5% SAT to about 2.5% SAT by weight.

[0112] Additionally, the batch composition may optionally include a surfactant. Non-limiting examples of surfactants that can be used in the batch composition include C8-C 22 Additional surfactant components that can be used with these fatty acids include C8-C 22 Fatty esters of C8-C 22and combinations thereof. Exemplary surfactants are stearic acid, lauric acid, myristic acid, oleic acid, linoleic acid, palmitoleic acid, and derivatives thereof, stearic acid in combination with ammonium lauryl sulfate, and combinations of all of these. The amount of surfactant may typically be from about 0.25% SAT to about 2% SAT by weight in the batch composition.

[0113] Pre-reacted particle composition Pre-reacted spherical inorganic particles are defined herein as spherical inorganic particles that have been at least partially reacted (e.g., formed by spray drying) (e.g., by being fired or calcined) to contain a desired ceramic crystal phase composition prior to being provided to a batch composition. Pre-reacted spherical inorganic particles may be formed from a mixture of constituent materials that react upon firing to produce an oxide or non-oxide ceramic. In some embodiments, multiple crystal phase compositions may be present within the calcined or fired particles. Pre-reacted organic spherical particles are formed to produce the desired spherical geometry with low aspect ratio AR as described herein.

[0114] Suitable processes for spray drying and calcining green inorganic particles are disclosed in WO 2016 / 138192 entitled "Ceramic Composite Beads And Methods For Making The Same" and WO 2014 / 189817 entitled "Porous Ceramic Article And Method Of Manufacturing The Same". Other spray drying processes suitable for producing pre-reacted organic particles may be used, such as the spray drying processes described in WO 2014 / 189,740 and WO 2014 / 189,741. As will become apparent, green spherical particles may be produced by a spray drying process and then calcined or fired to form pre-reacted spherical inorganic particles.

[0115] By way of example and without limitation, the pre-reacted spherical inorganic particles may comprise one or more phase compositions. In many embodiments, at least two-phase compositions are provided, such as a primary phase and a secondary phase or subphase. Optionally, the pre-reacted particles may comprise more than one secondary phase or subphase.

[0116] In some embodiments, the pre-reacted spherical inorganic particles in the batch composition may comprise a major phase of aluminum titanate (e.g., >50% by volume). Other minor phases may also be present.

[0117] In embodiments, the pre-reacted spherical inorganic particles in the batch composition may be formed to include any particular crystalline phase composition. In particular, the batch composition may, in some embodiments, include a multi-phase crystalline phase composition. For example, some embodiments may include pre-reacted spherical inorganic particles having a primary crystalline phase of aluminum titanate and a secondary glass phase.

[0118] For example, in one or more batch compositions, the pre-reacted spherical inorganic particles may comprise pre-reacted aluminum titanate-mullite spherical inorganic particles (hereinafter MAT) in which the primary crystalline phase is aluminum titanate and the secondary crystalline phase is mullite. Other minor phases may also be present.

[0119] The batch composition including the pre-reacted aluminum titanate-mullite spherical inorganic particles may be used to produce wet green bodies and porous ceramic bodies. For example, a green body honeycomb may be formed from the batch composition including the pre-reacted aluminum titanate-mullite spherical inorganic particles, which may be fired to produce an aluminum titanate-mullite porous ceramic honeycomb.

[0120] In other embodiments, the batch composition may include pre-reacted aluminum titanate-feldspar spherical inorganic particles, and the batch composition may be used to produce green bodies and porous ceramic bodies. The pre-reacted spherical inorganic particles may include a primary crystalline phase of aluminum titanate and a secondary crystalline phase of feldspar. For example, aluminum titanate-feldspar porous ceramic bodies (e.g., aluminum titanate-feldspar porous ceramic honeycombs) may be produced. Other minor phases may be present.

[0121] In yet another embodiment, the batch composition may include pre-reacted cordierite, mullite, aluminum titanate (hereinafter CMAT) spherical inorganic particles, and the batch composition may be used to produce green bodies and porous ceramic bodies. CMAT is a solid solution of a first crystalline phase, primarily aluminum titanate and magnesium dititanate, with a secondary crystalline phase including cordierite; a third crystalline phase of mullite. A glass phase may also be present. According to some embodiments, the pre-reacted spherical inorganic particles in the batch composition include, by weight percent on an oxide basis, 4%-10% MgO; 40%-55% Al2O3; 25%-44% TiO2, and 5-25% SiO2. CMAT porous ceramic bodies (e.g., CMAT porous ceramic honeycombs) may be produced from the batch composition.

[0122] In other embodiments, the batch composition includes pre-reacted cordierite particles, and the batch composition may be used to produce green bodies and cordierite ceramic bodies. For example, cordierite porous ceramic bodies (e.g., honeycomb green bodies and cordierite ceramic honeycombs) may be produced. As a non-limiting example, one composition of pre-reacted spherical inorganic particles that ultimately produces cordierite upon firing is, by weight percent, about 33-41% aluminum oxide, about 46-53% silica, and about 11-17% magnesium oxide.

[0123] The above-mentioned pre-reacted spherical inorganic particles are exemplary. The composition of the pre-reacted spherical inorganic particles may optionally include other ceramic-producing compositions and phase combinations. For example, the pre-reacted spherical inorganic particles may optionally have compositions including feldspar, mullite, alumina, aluminosilicate, solid solution of aluminum titanate and magnesium dititanate (pseudobrookite), spinel, rutile, cristobalite, zircon, alkali aluminosilicate, alkaline earth aluminosilicate, perovskite, zirconia, ceria, silicon oxide (SiO2), silicon nitride (Si3N4), silicon carbide, cerium titanate, sialon (SiAlON), CaO, SrO, CeO2, Y2O3, La2O3, other rare earth oxides, and zeolites.

[0124] Various example embodiments including various combinations of pre-reacted spherical inorganic particles and granules in the batch composition are shown in Table 2 below.

[0125] [Table 2]

[0126] Various embodiments showing the combinations of pore formers, organic binders, lubricants, and LV% in the batch compositions are shown in Table 3 below, listing the mass % SAT of the batch additions of pore formers, organic binders, lubricants, and LV%.

[0127] [Table 3]

[0128] Batch Rheology As noted above, using the batch compositions described herein, green bodies having well-defined walls, well-defined cell structures, and well-defined geometries (e.g., wet honeycomb green bodies) can be formed by extrusion. Furthermore, as will be appreciated, such batch compositions may, in some embodiments, have very high ratios of TauY / Beta (e.g., TauY / Beta≧2.0, TauY / Beta≧3.0, TauY / Beta≧4.0 or higher), and may further have elevated T onset ≧47℃, T onset ≧50℃, or even T onset ≧55° C. The pressure vs. temperature curve is characterized by a flat portion at low temperatures before a pressure increase at higher temperatures. onset is defined as when the pressure reaches 1.15 times the average pressure of the constant plateau pressure defined over a 15 degree window.

[0129] Thus, when the batch composition is extruded through the extrusion die 444 (FIG. 4A), a significantly higher extrusion feed rate is possible as compared to conventional batch compositions, which can contribute to lower costs in the manufacture of green bodies (e.g., wet green honeycomb bodies) and therefore can also reduce the cost of the final porous ceramic honeycomb body produced therefrom.

[0130] Tau Y and beta determination Homogeneous ceramic batch compositions including pastes were prepared from a mixture of batch minerals (pre-reacted spherical inorganic particles, and "granules"), pore former particles, organic binder, LV (e.g., deionized water), and optional lubricants by high shear mixing of the various components in a Brabender mixer (commercially available Brabender Plastograph EC 3.8 kW, 200 NM / 150 min equipped with mixer type 359). In some embodiments, paste stiffness was measured with a penetrometer to ensure proper paste consistency. A commercially available penetrometer ESM-301E motor-driven test stand equipped with a digital force gauge was used.

[0131] The paste flow properties of the batch composition are measured using a commercially available dual bore capillary rheometer (hereinafter "capillary rheometer") equipped with a piston and multiple capillary lengths. Both batch stiffness and wall resistance can be measured simultaneously with the capillary rheometer. An example of a capillary rheometer 900 is shown in FIG. 9.

[0132] The capillary rheometer 900 used comprises a number of cylindrical barrels 902 with a diameter D of 16 mm and several capillaries 908 of different lengths L with small circular bore holes with a capillary diameter d of 1 mm. The capillary lengths L ranged from 0 mm to 16 mm, specifically 0 mm (in practice 0.25 mm for practicality), 4 mm, 10 mm, and 16 mm. The disk-shaped pistons 904 were mounted for translational movement within the barrel 902 upon application of a force F to the pistons 904, such as by applying a force F to a cross member 906 interconnected to each of the pistons 904. After being mixed as described above, the batch composition 910 comprising the paste is inserted into the barrel 902 of the capillary rheometer 900 from where it is extruded into and through the capillaries 908 at various levels of force F, thus resulting in different velocities V. A representative pressure drop Ptotal across the capillary rheometer 900 is determined by measuring the pressure Ptotal and velocity Vp exerted on the piston 904 that contacts and extrudes the batch composition 910 through the capillary 908. The total pressure Ptotal in each die (e.g., a long die and a zero length die are shown) is determined from pressure sensors 912 that measure the pressure Ptotal exerted on the batch composition 910 contained within the barrel 902.

[0133] The velocity V of the batch composition 910 within the capillary 908 is related to the piston velocity Vp by a representative ratio of areas according to Equation 8 below: V = Vp(D 2 / d 2 ) Equation 8 The piston velocity Vp can be measured by a suitable displacement sensor 914 coupled between (i) the piston 904 or cross member 906 and (ii) either the ground or the extruder body comprising the barrel 902. The total pressure Ptotal and the piston velocity Vp can be provided to a suitable controller 916 equipped with a suitable processor and memory sufficiently configured to perform calculations that can provide as outputs the TauY and Beta values ​​of the batch composition.

[0134] Representative raw data from an exemplary capillary velocity sweep test showing four capillaries 908 of different lengths L (L of 16 mm, 10 mm, 4 mm, and 0.25 mm) and capillary diameter d of 1 mm for different extrusion rates is shown below in Table 4. The pushing speed of the piston 904 ("plunger") and the extrusion speed out of the capillary ("noodle") as well as the total pressure Ptotal are provided for each length L.

[0135] [Table 4]

[0136] When the shortest capillary 908 with a length L of 0.25 mm long (or about 0 mm long) is used for extrusion, the batch composition 910 must adapt its shape from the relatively large diameter D (16 mm) of the barrel 902 to the relatively small diameter d (1 mm) of the capillary 908. The pressure loss Ptotal across this capillary 908 (the "near zero capillary") corresponds to the batch stiffness due to the pressure required to geometrically shrink the batch composition from the 16 mm barrel to the 1 mm capillary 908. The use of the "near zero capillary" can indicate the entry loss component since the wall resistance component is minimal and therefore practically negligible due to its short length (near L=0) and can be used to determine the entry loss component. The use of a longer capillary (e.g., a 16 mm long capillary) results in both a wall resistance component due to friction / resistance along the length L of the capillary 908 wall and stiffening of the batch composition due to its change in shape, i.e., the entry loss component. Thus, the pressure drop Ptotal measured as a function of velocity V will include both an inlet loss component Pe and a wall resistance component Pw, which can be separated as will be apparent.

[0137] The batch compositions were tested by capillary velocity sweep testing for capillaries of different lengths, L (0 mm to 16 mm), at 10 different velocities V (effectively velocities (V) from 0 mm / sec to 4 in / sec (101.6 mm / sec)) and at a constant temperature of about 25° C. The extrusion velocity V (noodle) through the capillary 908 was increased to successively higher velocities V and for each step, a representative total pressure drop (Ptotal) was recorded by the sensor 912 when the steady state velocity V was reached. This raw Ptotal and velocity V data at each length L of the capillary 908 was provided to the controller 916 and stored in memory. Further calculations described herein are performed to calculate the Tau Y and Beta for each measured batch composition. Example values ​​are shown in Table 5 below for one batch composition.

[0138] [Table 5]

[0139] As shown in FIG. 10, a plot of inlet pressure Pe (psi) versus velocity V (inches / second) illustrates the non-linearity of the inlet pressure drop as a function of velocity V imparted by a zero-length (0.25 inch (approximately 6.35 mm)) capillary 908.

[0140] A representative example of raw data output from a capillary velocity sweep test with four different capillary sizes (0.25 mm to 16 mm) and ten different velocities is shown in FIG. 11, showing the test values ​​of a batch composition containing pre-reacted spherical inorganic particles in multiple steps and multiple curves, each corresponding to one capillary length (larger L values ​​indicate higher pressures). The sweep test is repeated two times in the example shown. The raw data can be converted into a plot of pressure versus velocity by using any suitable software program. An example plot of pressure versus velocity for a spray dried pre-reacted CMAT batch composition is shown in FIG. 12.

[0141] As stated above, the measured total pressure drop Ptotal is equal to the inlet pressure Pe plus the wall resistance contribution Pw and can be expressed by the following relationship: Ptotal = Pe + Pw Numerous models have been developed that relate the pressure drop of a batch composition 910 in a capillary rheometer 900 through a capillary 908 over a geometric contraction from D to d to batch rheology. Capillary characteristics include capillary diameter d, capillary length L, and constants that do not change for a given capillary 908 of a given length L and diameter d, with aspects related to the capillary material and capillary surface roughness. The test methods described herein are used to determine batch rheological characteristics including Tau Y (yield stress) and Beta (wall resistance coefficient), which are characteristic parameters that define the rheological properties of the various batch compositions described herein.

[0142] The Benbow-Bridgwater model is used to express the wall resistance Pw as a function of the capillary length L, the capillary diameter d, the velocity V, the wall resistance coefficient β (beta), and the wall velocity exponent m [see the following references: J. Benbow, J. Bridgwater, Paste flow and extrusion, Oxford University Press, 1993 and J.Benbow, E.W. Oxley, J. Bridgwater “The extrusion mechanics of pastes - the influence of paste formulation on extrusion parameters”; Chemical Eng. Science 53, 2151 (1987)]. This model characterizes the wall resistance Pw as the following Equation 9: Pw={4L / d}[βV m ] Formula 9 During the ceremony: L is the capillary length d is the capillary diameter β (beta) is the wall resistance coefficient m is the wall velocity exponent V is the velocity of the paste at the wall However, the shear stress at the wall, Tw, is given by Equation 10: Tw = βV m Formula 10 Therefore, the wall resistance pressure component can be expressed as follows: Pw=(4L / d)Tw Equation 11 The natural log of shear stress (Ln(Tw)) is plotted against the natural log of velocity (Ln(V)). From this plotted data, the β term can be derived as the y-intercept of the plot of Ln(Tw) vs. Ln(V), and m is the slope of the line. Determine the slope m over the length data from 0 in / sec to 4 in / sec (0 mm / sec to approximately 101.6 mm / sec). Outliers should be ignored and the test should be performed multiple times and the results averaged for each batch composition.

[0143] The inlet pressure Pe can be approximated by the following equation 12: Pe=2{tauY+kV n}{Ln(D / d)} Equation 12 Considering that Ptotal=Pe+Pw, this model defines the total pressure P as shown in Equation 13 below: Ptotal = 2{Tau Y + kV n}{Ln(D / d)}+{4L / d}[βV m ] Formula 13 During the ceremony: Tau Y is the yield stress of the batch composition k is the viscosity index n is the bulk velocity exponent D is the extruder barrel diameter d is the capillary diameter L is the capillary length β (beta) is the wall resistance coefficient m is the wall velocity exponent V is the velocity of the paste at the wall The values ​​of TauY, k, and n can be derived from the measured data by a three-parameter curve fit using a solver, such as the one provided in MS Excel or any other iterative solver, to minimize the difference between the measured and calculated parameters. The values ​​of TauY and β (beta) are parameters used herein to characterize the extrusion rheological properties of the batch compositions described herein and are calculated as described above. From this measured raw data, the controller 916 calculates both TauY and beta.

[0144] More specifically, Figure 7 shows a plot comparing the LV% (% SAT by weight of liquid vehicle) used in various embodiments of batch compositions containing pre-reacted spherical inorganic particles with the LV% of conventional batch compositions. As can be seen, comparable batch stiffness TauY can be achieved in many cases despite much higher LV%. For example, comparable TauY can be achieved with LV% that is twice as high or even higher while still achieving good batch stiffness.

[0145] FIG. 8 shows a plot of LV% (moisture at mass % SAT) vs. batch friction (beta (β)) of a conventional batch composition compared to various embodiments of a batch composition including pre-reacted spherical inorganic particles according to the embodiments. As shown by the plot in FIG. 8, a much lower beta is achieved when using a batch composition including pre-reacted spherical inorganic particles, a small amount of "fines", and LV%≧28%. As can be seen from FIG. 8 and Table 6 below, according to the embodiments of the batch composition described herein, a relatively low beta (coefficient of friction) can be achieved by the batch composition, such as beta≦10, beta≦7, beta≦6, beta≦5, beta≦4, and even beta≦3.

[0146] Figure 13 shows a plot of LV% (water at mass % SAT) versus the ratio of TauY divided by Beta (β) for a conventional batch composition and various embodiments of a batch composition including pre-reacted spherical inorganic particles according to embodiments. As shown by the plot in Figure 13 and Table 6 below, the ratio of TauY / β is significantly higher in the batch compositions described herein than in the conventional batch compositions.

[0147] For example, some embodiments shown in FIG. 13 and Table 6 below may have a ratio of TauY / Beta that may be TauY / Beta≧2.0, TauY / Beta≧3.0, TauY / Beta≧4.0, TauY / Beta≧5.0, TauY / Beta≧6.0, TauY / Beta≧7.0, TauY / Beta≧8.0, or even TauY / Beta≧10.0. In some embodiments, the ratio of TauY / Beta may be 2.0≧TauY / Beta≧10.0. As will be appreciated, the value of TauY / Beta, which correlates with extrusion rate, is significantly higher than conventional batches and may range from about 0.85 to 1.50. Thus, batch compositions exhibiting values ​​of TauY / Beta may achieve relatively high extrusion rates.

[0148] Table 6 below shows the LV%(SAT), liquid to organic binder ratios for various embodiments of batch compositions, as well as rheological measurements of Tau-Y, Beta, and Tau-Y / Beta.

[0149] [Table 6]

[0150] processing In another aspect, as shown generally in FIG. 5 and more specifically in FIG. 6, the present disclosure provides a method 500, 600 for manufacturing a honeycomb body. The method 500, 600 can have a high extrusion rate when formed through an extrusion die 444 (FIG. 4A) compared to a batch composition including conventional reactive batch components. The method 500, 600 for manufacturing includes providing a batch composition including pre-reacted spherical inorganic particles, a small amount of "fines" and a high LV% (e.g., ≧28%) at 502, 602. In FIG. 6, the batch composition is specifically provided at 602 with: 20μm≦D 50 ≦50μm, D 90 ≦100 μm, and D 10 ≧5μm and fine inorganic particles ("fines") in an amount of less than 20 wt.% SAP, the "fines" having a median diameter of less than 5 μm, and an LV% of 28 wt.% or greater by top-up addition to all inorganic particles in the batch composition. The batch composition may further include added organic binders, lubricants, surfactants, and / or optional pore formers, as described herein.

[0151] The method 500, 600 further includes mixing the batch composition at 504, 604. The mixing step at 604 may include the addition of LV and lubricant to the dry ingredients (pre-reacted spherical inorganic particles, fine inorganic particles, and organic binder) to at least partially plasticize the batch composition, i.e., provide a paste consistency.

[0152] The method 500 further includes forming the batch composition into a wet green honeycomb body at 506. The forming at 606 may be by extrusion, where the batch composition properties include TauY / Beta > 2.0, thereby enabling significantly higher extrusion rates through the extrusion die 444. Shape control is maintained.

[0153] According to method 500, LV (e.g., deionized water) may be added at a LV% of LV≧28% SAT relative to the total amount of pre-reacted inorganic particles and organic particles. In other embodiments, LV≧30%, LV%≧35%, LV%≧40%, or even LV%≧45% superaddition (SAT) may be added by mass based on the total mass of inorganic particles present in the batch composition (pre-reacted spherical inorganic particles plus "fines"). In some embodiments, the LV% is such that 28%≦LV%≦50%.

[0154] The extrusion method 500 may include the addition of an organic binder, such as in an amount between about 4.0% SAT and 8.0% SAT by weight. The organic binder may be a combination of methylcellulose binder and hydroxymethylcellulose binder, in some embodiments, where the methylcellulose binder is between about 3.0% SAT and 6.0% SAT by weight and the hydroxymethylcellulose binder is between about 1.5% SAT and 3.0% SAT by weight. Some embodiments may include only hydroxymethylcellulose binder, for example, in an amount between about 4.0% SAT and 8.0% SAT by weight.

[0155] To initiate plasticization, the inorganic particles, organic binder, optional pore former, LV, and lubricant may be mixed at 504, 604 by any suitable mixing device or combination of mixing devices, such as by a muller, auger mixer, double arm mixer, or plow blade mixer or the like. LV may be added to hydrate the organic binder and inorganic particles, and lubricants and / or surfactants may be added to the batch composition to wet out the organic binder and inorganic particles and generate a partially plasticized batch composition. At 506, the batch composition may be suitably formed from the plasticized batch composition 404 into a wet green honeycomb body 446W by any suitable forming process. For example, the wet green honeycomb body 446W may be fabricated by forming techniques such as uniaxial or isostatic pressing, injection molding, extrusion, or the like.

[0156] The batch composition, in some embodiments, may be produced as a partially plasticized pug 402 of material, which may be fed into an extruder 400 as shown in Figure 4A. In other embodiments, the batch composition may be added to the extruder 400 in a continuous or semi-continuous stream of smaller amounts of material, such as small pugs or even granules or streams of the partially plasticized batch composition. As shown in Figure 4A and described with reference to Figure 5, the partially plasticized batch composition 404 may be formed into a wet green honeycomb body 446W at 506, 606.

[0157] 4A and 5, the batch composition 404 in the form of one or more pugs 402 can be provided to an extruder 400 from which it can be extruded to form and shape the batch composition into a wet green honeycomb body 446W. The extrusion can be performed by any suitable type of extruder 400 that imparts a suitable amount of shear to the batch composition 404. For example, a hydraulic ram extruder, a two-stage degassing single auger, a single screw extruder, or a twin screw extruder, etc., may be used. An example of the formation and shaping of a wet green honeycomb body 446W using an extruder 400 equipped with one or more screws is shown in FIG. 4A.

[0158] More specifically, the extruder 400 may include a screw section that includes one or more extruder screws 418 rotatable within an extruder barrel 420. The one or more extruder screws 418 may be driven by a motor 422 at the inlet end of the extruder barrel 420. In a twin screw embodiment, the extruder 400 may include two of the extruder screws 418. The extruder barrel 420 may include an inlet port 424 for introducing the batch composition 404 to be further plasticized into the extruder 400. A mixer plate 426 may be located downstream of the screw section and may be housed within a cartridge 428 attached to the outlet end of the extruder barrel 420. After the screw section, the mixer plate 426 further mixes, homogenizes, and plasticizes the batch composition 404.

[0159] Also disposed within the cartridge 428 are a filter screen 410 and a filter support 430, both of which are disposed upstream of the mixer plate 426 relative to the flow direction (shown as a directional arrow) of the batch composition 404 delivered by the extruder screw 418. The filter screen 410 is attached to the filter support 430 to form a filter assembly configured to remove larger particles, agglomerates, or debris that may block the extrusion die 444. The filter support 430 is preferably formed with a plurality of openings and / or slots. The extruder 400 further comprises an extrusion die 444 attached at the discharge end of the cartridge 428 downstream of the filter assembly and the mixer plate 426. The die comprises a plurality of upstream feed holes and a plurality of downstream cross slots. The filter assembly is operable to remove larger agglomerates and debris that may block the slots of the extrusion die 444. Flow of plasticized batch composition 404 through a plurality of intersecting slots in extrusion die 444 forms a matrix of intersecting walls 102 and channels 104 in wet green honeycomb body 446W that correspond to honeycomb body 446D.

[0160] Thus, during operation of the extruder 400, the plasticized batch composition 404 is forced through the extruder barrel 420 by one or more extruder screws 418, then through a filter screen 410, a filter support 430, and a mixer plate 426, and finally discharged from the extrusion die 444 of the extruder 400 as a wet green honeycomb body 446W. The wet green honeycomb body 446W may be cut by a cutting device 448 comprising a cutting tool such as a wire. Once cut, the wet green honeycomb body 446W may be received on a tray 450.

[0161] The wet green honeycomb body 446W may then be dried and conveyed by trays 450 and conveyors (not shown) to a dryer (not shown) where it is dried at 508 by any suitable drying process, such as, for example, oven drying, microwave drying, RF drying, combinations thereof, etc., to form a dried green body honeycomb 446D (FIG. 4B). The dried green body honeycomb 446D comprises a plurality of intersecting walls 102 that extend from one end of the green body honeycomb 446D to the other. The intersecting walls 102 form channels 104 that also extend from end to end.

[0162] Firing The dried green body honeycomb 446D can then be fired at 510 according to known firing techniques to form the porous ceramic honeycomb body 101 as shown in Figure 1. For example, the dried green honeycomb body 446D may be fired in a gas kiln or an electric kiln under conditions effective to convert the dried green body honeycomb 446D into a ceramic article (e.g., the porous ceramic honeycomb body 101). The firing conditions of temperature and time depend on the particular batch composition and size and geometry of the dried green body honeycomb 446D.

[0163] For example, firing conditions effective for converting the dried green honeycomb 446D to a porous ceramic honeycomb body 101 may include, for example, heating the dried green honeycomb 446D in an air atmosphere in a furnace at a heating rate of 120°C / hour to a maximum soak temperature in the range of 1000°C to 1600°C, depending on the batch composition. The maximum soak temperature may be held for a holding time of about 1 to 30 hours sufficient to convert the dried green honeycomb 446D to a ceramic article. This may be followed by cooling at a rate low enough (e.g., a cooling rate of about 10 to 160°C / hour) to avoid thermally shocking the porous ceramic honeycomb body 101 into cracks. The firing time may further depend on factors such as the type and amount of particulate material and pore former(s), as well as the nature of the firing equipment, but the total firing time may be, for example, about 20 hours to about 80 hours.

[0164] For batch compositions primarily for producing aluminum titanate compositions, the maximum firing temperature is about 1300° C. to about 1450° C., and the holding time at this temperature is about 1 hour to about 6 hours.

[0165] For batch compositions intended to produce primarily an aluminum titanate-mullite phase composition, the maximum firing temperature is from about 1340° C. to about 1500° C., and the holding time at this temperature is from about 1 hour to about 6 hours.

[0166] For batch compositions intended to produce a primarily cordierite-mullite, aluminum titanate (CMAT) phase composition, the maximum firing temperature is from about 1300° C. to about 1380° C., with a hold time at this temperature of from about 1 hour to about 6 hours.

[0167] For batch compositions primarily for producing mullite, the maximum firing temperature is about 1400° C. to about 1600° C., and the holding time at this temperature is about 1 hour to about 6 hours.

[0168] For the cordierite-mullite producing mixture that gives the cordierite-mullite composition described above, the maximum firing temperature is about 1375° C. to about 1425° C., and the holding time at this temperature is about 1 hour to about 6 hours.

[0169] For example, in a composition for mainly producing cordierite, the maximum firing temperature is about 1300° C. to about 1450° C., and the holding time at this temperature is about 1 hour to about 6 hours.

[0170] Porous ceramic articles produced from batch compositions Porous ceramic articles (e.g., porous ceramic honeycomb bodies) produced from batch compositions including pre-reacted spherical inorganic particles, a relatively small amount of "fines" (≦20 wt.% SAP of a particle distribution having a median particle size of less than 5 μm) and LV%≧28%, after firing, may exhibit interconnected open pores and a microstructure suitable for use as catalyst supports and / or particulate filters.

[0171] For example, some embodiments may provide a relatively large median pore size (MPS), high porosity (%P), good strength and low coefficient of thermal expansion (CTE) that allows for both low pressure drop and good thermal shock resistance when embodied as a particulate filter.

[0172] According to example embodiments of the present disclosure, the porous ceramic honeycomb body 101 (FIG. 1) having an inverted pore structure provides relatively high permeability. For example, the porous ceramic honeycomb body may have a porosity of greater than 50%, greater than 55%, or even greater than 60% in some embodiments. The porous ceramic honeycomb body 101 may have a median pore size (d50) of greater than 10 μm, or even greater than 15 μm, and between 10 μm and 30 μm in some embodiments.

[0173] The porous ceramic honeycomb body 101 is 20×10 -7 K -1 Less than, for example, 15 x 10 -7 K -1 Less than or even 10x10 -7 K -1 The (300 / 14) honeycomb body of the porous ceramic honeycomb body 101 may have a coefficient of thermal expansion from room temperature (RT) to 800° C. of less than 100° C. Additionally, the (300 / 14) honeycomb body of the porous ceramic honeycomb body 101 may have a modulus of rupture (MOR) flexural strength of, for example, greater than 170 psi (about 1.17 MPa), or even greater than 200 psi (about 1.38 MPa).

[0174] FIG. 1 illustrates an isometric view of a porous ceramic honeycomb article 100 according to an exemplary embodiment of the present disclosure. The porous ceramic honeycomb article 100 is embodied as a particulate filter and includes a first end 108, which may be an inlet end, a second end 110 opposite the first end 108, and a plurality of inlet channels 104 extending from the first end 108 to the second end 110. Similarly, a plurality of outlet channels 106 also extend from the first end 108 to the second end 110. A plurality of intersecting walls 102 form the inlet channels 104 and the outlet channels 106, forming a honeycomb matrix. The first end 108 may include a plug 112 at the first end 108 of the outlet channel 106. Similarly, the second end 110 (outlet end) may include a plug 112 (not shown in FIG. 1) at the end of the inlet channel 104. Thus, in some embodiments, a checkerboard pattern of plugs 112 may be formed at both the first end 108 and the second end 110. Other plug configurations may be used having partial plug configurations where some channels are blocked and some channels are unblocked, i.e., flow-through channels. Porosity, median pore size, and pore size distribution were determined by tomography.

[0175] The cell density of the porous ceramic honeycomb body 101 can be about 70 to 1200 cells per square inch (cpsi) (about 10 to 190 cells per square centimeter). The cell wall thickness can range from about 0.025 mm to about 1.5 mm (about 0.001 to 0.060 inches). For example, the geometry of the porous ceramic honeycomb body 101 can be 400 cpsi (62 cells per square centimeter) with a wall thickness of about 8 mils (about 0.2 mm) (400 / 8) or a wall thickness of about 6 mils (about 0.15 mm) (400 / 6). Other geometries may include, for example, 100 / 17, 200 / 12, 200 / 19, 270 / 19, 350 / 3, 400 / 3, 400 / 4, 500 / 2, 600 / 2, 600 / 3, 600 / 4, 750 / 2, 900 / 2, 900 / 3, 1200 / 2, and even 750 / 1 and 900 / 1. Other suitable combinations may be produced using the batch composition.

[0176] As used herein, a porous ceramic honeycomb body is intended to have any honeycomb structure, i.e., cell shape, and is not strictly limited to a square cell shape. For example, the cells of the porous ceramic honeycomb body 101 may be square, rectangular, hexagonal, octagonal, triangular, or any other suitable cell shape. Also, although the cross-section of the porous ceramic honeycomb body 101 shown is circular, the cross-sectional shape is not so limited. For example, the cross-sectional shape can be oval, racetrack, square, rectangular, or any other desired geometric shape.

[0177] Disposed on the periphery of the matrix of intersecting walls 102 is the peripheral surface. The peripheral surface may have a skin 105 herein, and in some embodiments may be formed as a co-extruded skin formed simultaneously with the intersecting walls 102. In other embodiments, a subsequently applied exterior skin may form the peripheral surface that extends axially from a first end face to a second end face of the porous ceramic honeycomb body 101. As used herein, the porous ceramic honeycomb body 101 includes ceramic honeycomb monoliths as well as ceramic segmented honeycomb bodies, i.e., ceramic honeycomb segments bonded together.

[0178] It will be apparent to those skilled in the art that various changes and modifications can be made in the present disclosure without departing from the scope of the present disclosure. Therefore, if the changes and modifications of the present disclosure are within the scope of the appended claims and their equivalents, the present disclosure is intended to cover such changes and modifications.

[0179] Preferred embodiments of the present invention will be described below in detail.

[0180] EMBODIMENT 1 In the batch composition 20μm≦D 50 ≦50μm, D 90 ≦100 μm, and D10 ≧5μm and pre-reacted spherical inorganic particles having a narrow particle size distribution of less than 20% by weight of fine inorganic particles based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm; and an LV% of 28% by weight or more by top-up addition to all inorganic particles in the batch composition; LV% is the liquid vehicle percent, and 90% of the pre-reacted inorganic particles in the particle size distribution are D 90 and 10% of the pre-reacted inorganic particles have a diameter of less than or equal to D 10 It has a diameter of D 50 is the median particle size of said particle size distribution.

[0181] EMBODIMENT 2 The pre-reacted spherical inorganic particles are 20 μm≦D 50 2. The batch composition of embodiment 1, having a particle size of ≦45 μm.

[0182] EMBODIMENT 3 The pre-reacted spherical inorganic particles are 25 μm≦D 50 3. The batch composition of embodiment 2 having a particle size of ≦45 μm.

[0183] EMBODIMENT 4 D 90 2. The batch composition of embodiment 1, having a particle size of ≦75 μm.

[0184] EMBODIMENT 5 D 90 5. The batch composition of embodiment 4 having a particle size of ≦65 μm.

[0185] EMBODIMENT 6 D 10 2. The batch composition of embodiment 1, having a particle size of ≧10 μm.

[0186] EMBODIMENT 7 D 10 2. The batch composition of embodiment 1, having a particle size of ≧25 μm.

[0187] EMBODIMENT 8 D 90 ≦75μm and D 10 2. The batch composition of embodiment 1, having a particle size of ≧5 μm.

[0188] EMBODIMENT 9 D 90 ≦65μm and D 10 9. The batch composition of embodiment 8, having a particle size of ≧5 μm.

[0189] EMBODIMENT 10 D 90 ≦70μm and D 10 2. The batch composition of embodiment 1, having a particle size of ≧10 μm.

[0190] EMBODIMENT 11 The pre-reacted spherical inorganic particles have a dB≦2.00, B =(D 90 -D 10 ) / D 50 2. The batch composition of embodiment 1, wherein

[0191] EMBODIMENT 12 12. The batch composition of embodiment 11, wherein the pre-reacted spherical inorganic particles have a dB≦1.00.

[0192] EMBODIMENT 13 12. The batch composition of embodiment 11, wherein the pre-reacted spherical inorganic particles have a dB≦0.90.

[0193] EMBODIMENT 14 12. The batch composition of embodiment 11, wherein the pre-reacted spherical inorganic particles have a dB≦0.80.

[0194] EMBODIMENT 15 2. The batch composition of embodiment 1, comprising less than 15% by weight of fine inorganic particles having a fine particle size distribution with a median diameter of less than 5 μm.

[0195] EMBODIMENT 16 16. The batch composition of embodiment 15, comprising less than 10% by weight of fine inorganic particles having a median diameter of less than 5 μm.

[0196] EMBODIMENT 17 2. The batch composition of embodiment 1, wherein the fine inorganic particles in the batch composition comprise fine alumina and fine silica, each having a median diameter of less than 2 μm.

[0197] EMBODIMENT 18 2. The batch composition of embodiment 1, wherein the fine inorganic particles in the batch composition comprise fine alumina and colloidal silica, each having a particle size distribution with a median diameter of less than 1 μm.

[0198] EMBODIMENT 19 2. The batch composition of embodiment 1, having a ratio of the total mass of the fine inorganic particles in the batch composition to the total mass of the pre-reacted spherical inorganic particles in the batch composition of 3:97 to 20:80.

[0199] EMBODIMENT 20 2. The batch composition of embodiment 1, wherein the pre-reacted spherical inorganic particles have an AR≦1.2, where AR is the average aspect ratio measured across a first width having a maximum dimension and divided by a second width having a minimum dimension across the pre-reacted spherical inorganic particles.

[0200] EMBODIMENT 21 2. The batch composition of embodiment 1, wherein the pre-reacted spherical inorganic particles are formed by a spray drying process.

[0201] EMBODIMENT 22 2. The batch composition of embodiment 1, wherein the weight percent of the liquid vehicle is 30% or greater by weight by superaddition based on the total weight of all inorganic particles in the batch composition.

[0202] EMBODIMENT 23 2. The batch composition of embodiment 1, wherein the weight percent of the liquid vehicle is 35% or greater by weight by superaddition based on the total weight of all inorganic particles in the batch composition.

[0203] EMBODIMENT 24 2. The batch composition of embodiment 1, wherein the weight percent of the liquid vehicle is 40% or greater by weight by superaddition based on the total weight of all inorganic particles in the batch composition.

[0204] EMBODIMENT 25 2. The batch composition of embodiment 1, wherein the weight percent of the liquid vehicle is 45% or greater by weight by superaddition based on the total weight of all inorganic particles in the batch composition.

[0205] EMBODIMENT 26 2. The batch composition of embodiment 1, wherein the weight percent of the liquid vehicle is from 28% to 50% by weight by superaddition based on the total weight of all inorganic particles in the batch composition.

[0206] EMBODIMENT 27 2. The batch composition of embodiment 1, comprising a combination of starch and graphite as pore formers.

[0207] EMBODIMENT 28 Pea starch as a pore former in an amount of 5% to 20% by weight by top-up addition to all inorganic particles in the batch composition; and Graphite as a pore former in an amount of 1% to 10% by weight by top-addition to all of the inorganic particles in the batch composition. 2. The batch composition of embodiment 1, comprising a combination of:

[0208] EMBODIMENT 29 2. The batch composition of embodiment 1, comprising a spherical polymeric pore former.

[0209] EMBODIMENT 30 2. The batch composition of embodiment 1, comprising a lubricant in an amount of 0.5% to 2.5% by weight by superaddition relative to the weight of all of the inorganic particles in the batch composition.

[0210] EMBODIMENT 31 2. The batch composition of embodiment 1, comprising an organic binder in an amount of 4.0% to 8.0% by weight based on the weight of all of the inorganic particles in the batch composition by top-up addition.

[0211] EMBODIMENT 32 32. The batch composition of embodiment 31, wherein the organic binder comprises a combination of a methylcellulose binder and a hydroxymethylcellulose binder, the methylcellulose binder being from about 3.0% SAT to 6.0% SAT by weight, and the hydroxymethylcellulose binder being from about 1.5% SAT to 3.0% SAT by weight, where SAT is defined as an over-addition to the weight of all inorganic particles in the batch composition.

[0212] EMBODIMENT 33 32. The batch composition of embodiment 31, wherein the organic binder comprises only hydroxymethyl cellulose binder as the organic binder in an amount of about 4.0 wt.% SAT to 8.0 wt.% SAT, where SAT is defined as the superaddition to the weight of all inorganic particles in the batch composition.

[0213] EMBODIMENT 34 2. The batch composition of embodiment 1, wherein the pre-reacted spherical inorganic particles comprise a predominant crystalline phase of aluminum titanate.

[0214] EMBODIMENT 35 2. The batch composition of embodiment 1, wherein the pre-reacted spherical inorganic particles comprise a primary crystalline phase of aluminum titanate and a secondary crystalline phase of mullite.

[0215] EMBODIMENT 36 2. The batch composition of embodiment 1, wherein the pre-reacted spherical inorganic particles comprise a primary crystalline phase of aluminum titanate and a secondary crystalline phase of feldspar.

[0216] EMBODIMENT 37 2. The batch composition of embodiment 1, wherein the pre-reacted inorganic particles comprise a first crystalline phase that is primarily a solid solution of aluminum titanate and magnesium dititanate, and a second crystalline phase that comprises cordierite.

[0217] EMBODIMENT 38 2. The batch composition of embodiment 1, wherein the pre-reacted spherical inorganic particles comprise a primary crystalline phase of aluminum titanate and a secondary glassy phase.

[0218] EMBODIMENT 39 2. The batch composition of embodiment 1, wherein the pre-reacted inorganic particles comprise, by weight percent on an oxide basis, 4%-10% MgO, 40%-55% Al2O3, 25%-44% TiO2, and 5-25% SiO2.

[0219] EMBODIMENT 40 2. The batch composition of embodiment 1 having a liquid vehicle to organic binder ratio of ≧6.4%.

[0220] EMBODIMENT 41 2. A green honeycomb body comprising the batch composition of embodiment 1.

[0221] EMBODIMENT 42 1. A method for manufacturing a honeycomb body, comprising: 20μm≦D 50 ≦50μm, D 90 ≦100 μm, and D 10 ≧5μm and pre-reacted spherical inorganic particles having a particle size distribution of less than 20% by weight of fine inorganic particles based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm; and a LV% of at least 28% by weight of the total inorganic particles in the batch composition, 90% of the pre-reacted spherical inorganic particles are D 90 and 10% of the pre-reacted spherical inorganic particles have a diameter less than D 10 has a diameter less than D 50 is the median particle size; forming the batch composition into a wet green honeycomb body by extrusion, wherein the batch composition has a TauY / Beta≧2.0, where TauY is a measure of batch stiffness and Beta is the coefficient of friction of the batch composition; A method comprising:

[0222] EMBODIMENT 43 The method of embodiment 42, wherein TauY / Beta is >= 3.0.

[0223] EMBODIMENT 44 The method of embodiment 42, wherein TauY / Beta is >= 4.0.

[0224] EMBODIMENT 45 The method of embodiment 42, wherein TauY / Beta is >= 5.0.

[0225] EMBODIMENT 46 The method of embodiment 42, wherein TauY / Beta is >= 6.0.

[0226] EMBODIMENT 47 The method of embodiment 42, wherein TauY / Beta is >= 7.0.

[0227] EMBODIMENT 48 The method of embodiment 42, wherein TauY / Beta is >= 8.0.

[0228] EMBODIMENT 49 The method of embodiment 42, wherein TauY / Beta is >= 10.0.

[0229] EMBODIMENT 50 The forming step includes extrusion, and a T during the extrusion of 47° C. or greater. onset 43. The method of embodiment 42, comprising:

[0230] EMBODIMENT 51 T during the extrusion of 50°C or more onset 51. The method of embodiment 50, comprising:

[0231] EMBODIMENT 52 T during the extrusion of 55°C or more onset 51. The method of embodiment 50, further comprising:

[0232] EMBODIMENT 53 drying the wet green honeycomb body to form a dried green honeycomb body; firing the dried green honeycomb body to form a porous ceramic honeycomb body. 43. The method of embodiment 42, comprising:

[0233] EMBODIMENT 54 1. A method for manufacturing a honeycomb body, comprising: mixing pre-reacted spherical inorganic particles and a batch composition comprising fine inorganic particles with an over-addition of less than 20% by weight based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm, and an over-addition LV% of 28% by weight or more based on all inorganic particles in the batch composition; forming the batch composition into a wet green honeycomb body by extrusion, wherein the batch composition has a TauY / Beta≧2.0, where TauY is a measure of batch stiffness and Beta is the coefficient of friction of the batch composition; A method comprising:

[0234] EMBODIMENT 55 In the batch composition 20μm≦D 50 ≦50μm, D 90 ≦100 μm, and D10 ≧5μm and pre-reacted spherical inorganic particles having a narrow particle size distribution of less than 20% by weight of fine inorganic particles based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm; and a LV% of 28% by weight or more by top-up addition to all inorganic particles in the batch composition; and having tauY / beta≧2.0; LV% is the liquid vehicle percent, and 90% of the pre-reacted inorganic particles in the particle size distribution are D 90 and 10% of the pre-reacted inorganic particles have a diameter of less than or equal to D 10 It has a diameter of D 50 is the median particle size of said particle size distribution, TauY is a measure of batch stiffness, and Beta is the coefficient of friction of said batch composition.

Claims

1. In the batch composition 20μm≦D ５０ ≦50μm、 D ９０ ≦100 μm, and D １０ ≧5μm Spherical inorganic particles having a narrow particle size distribution of less than 20% by weight of fine inorganic particles based on the total weight of the spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm; and an LV% of 28% by weight or more by top-up addition to all inorganic particles in the batch composition; LV% is the liquid vehicle percent, and 90% of the spherical inorganic particles in the particle size distribution are D ９０ and 10% of said spherical inorganic particles have a diameter of D １０ and has a diameter of D ５０ is the median particle size of the particle size distribution, the ratio of the total mass of the fine inorganic particles in the batch composition to the total mass of the spherical inorganic particles in the batch composition is 3:97 to 20:80; The spherical inorganic particles comprise a desired ceramic crystalline phase composition. Batch Composition.

2. D １０ 2. The batch composition of claim 1 having a particle size of > 25 μm.

3. 10. The batch composition of claim 1 having a liquid vehicle to organic binder ratio of ≥ 6.4%.

4. 1. A method for manufacturing a honeycomb body, comprising: 20μm≦D ５０ ≦50μm、 D ９０ ≦100 μm, and D １０ ≧5μm and pre-reacted spherical inorganic particles having a particle size distribution of fine inorganic particles, by top-up addition of more than 3% and less than 20% by weight based on the total weight of the pre-reacted spherical inorganic particles in the batch composition, the fine inorganic particles having a median diameter of less than 5 μm; and 28 wt. % LV of all inorganic particles in the batch composition, wherein the pre-reacted spherical inorganic particles are formed by firing or calcining spherical inorganic particles formed by spray drying to have a desired ceramic crystalline phase composition, and 90% of the pre-reacted spherical inorganic particles are D ９０ and 10% of the pre-reacted spherical inorganic particles have a diameter less than D １０ has a diameter less than D ５０ is the median particle size; forming the batch composition into a wet green honeycomb body by extrusion; A method comprising:

Images