阅读说明：本技术 包含球形预反应过的无机颗粒和球形造孔剂的批料组合物及由其制造蜂窝体的方法 (Batch composition comprising spherical pre-reacted inorganic particles and spherical pore formers and method for producing honeycomb bodies therefrom ) 是由 M·贝克豪斯-里考特 C·克拉德 B·N·特维克夫 于 2018-10-31 设计创作，主要内容包括：包含预反应过的无机球形颗粒和造孔剂球形颗粒的批料组合物。所述预反应过的无机球形颗粒具有粒度分布,其中,10μm≤DI<Sub>50</Sub><50μm,并且DIb≤2.0,并且造孔剂球形颗粒具有粒度分布,其中,0.40DP<Sub>50</Sub>≤DI<Sub>50</Sub><0.90DP<Sub>50</Sub>,并且DPb≤1.32,其中,DI<Sub>50</Sub>是预反应过的无机球形颗粒的分布的中位颗粒直径,DP<Sub>50</Sub>是造孔剂粒度分布的中位颗粒直径,DIb是预反应过的无机球形颗粒的预反应后的粒度分布的宽度因子,并且DPb是造孔剂粒度分布的宽度因子。还提供了由所述批料组合物制造的生坯蜂窝体,以及使用所述批料组合物制造蜂窝体的方法。(A batch composition comprising pre-reacted inorganic spherical particles and pore former spherical particles. The pre-reacted inorganic spherical particles have a particle size distribution wherein DI is 10 μm or less 50 <50 μm and DIb ≤ 2.0, and the spherical particles of the pore-forming agent have a particle size distribution of 0.40DP 50 ≤DI 50 <0.90DP 50 And DPb ≦ 1.32, wherein DI 50 Is the median particle diameter, DP, of the distribution of the pre-reacted inorganic spherical particles 50 Is the median particle diameter of the pore former particle size distribution, DIb is the width factor of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles, and DPb is the width factor of the pore former particle size distribution. Green honeycomb bodies made from the batch compositions are also provided, as well as methods of making honeycomb bodies using the batch compositions.)

1. A batch composition, comprising:

pre-reacted inorganic spherical particles having a pre-reacted particle size distribution, wherein:

10μm≤DI₅₀less than or equal to 50 μm, and

DIb is less than or equal to 2.0; and

a pore former spherical particle having a pore former particle size distribution, wherein:

0.40DP₅₀≤DI₅₀≤0.90DP₅₀and is and

DPb ≦ 1.32, and

wherein DI₅₀Median particle diameter, DP, of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles₅₀Is the median particle diameter of the pore-forming agent particle size distribution of the pore-forming agent spherical particles, DIb is the width factor of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles, and DPb is the width factor of the pore-forming agent particle size distribution of the pore-forming agent spherical particles.

2. The batch composition of claim 1, comprising less than 20% fine inorganic particles based on the total weight of the pre-reacted inorganic spherical particles, wherein the fine inorganic particles have a median diameter of less than 5 μ ι η.

3. The batch composition of claim 1, wherein the batch composition comprises less than 10% fine inorganic particles based on the total weight of the pre-reacted inorganic spherical particles, wherein the fine inorganic particles have a median diameter of less than 5 μ ι η.

4. The batch composition of claim 1, wherein the batch composition comprises less than 5% fine inorganic particles based on the total weight of the pre-reacted inorganic spherical particles, wherein the fine inorganic particles have a median diameter of less than 5 μ ι η.

5. The batch composition of claim 1 wherein the pre-reacted inorganic spherical particles have AR_Average≤1.2，

Wherein, AR_AverageIs the average aspect ratio, which is defined as the largest width dimension divided by the smallest width dimension of the pre-reacted inorganic spherical particles on average.

6. The batch composition of claim 1 wherein the pore former spherical particles have AR_Average≤1.1，

Wherein, AR_AverageIs the average aspect ratio, which is defined as the largest width dimension divided by the smallest width dimension of the spherical particles of the pore former, on average.

7. The batch composition of claim 1, comprising 20 μm DI₅₀≤50μm。

8. The batch composition of claim 1, comprising 20 μm DI₅₀≤40μm。

9. The batch composition of claim 1, comprising DI₉₀≤85μm。

10. The batch composition of claim 1, comprising DI₉₀≤65μm。

11. The batch composition of claim 1 comprising 45 μm DI₉₀≤85μm。

12. The batch composition of claim 1, comprising DI₁₀≥8μm。

13. The batch composition of claim 12 comprising 8 μm DI₁₀≤35μm。

14. The batch composition of claim 1, comprising (DI)₉₀-DI₁₀)≤55μm。

15. The batch of claim 1A composition comprising 15 μm ≦ (DI)₉₀-DI₁₀)≤55μm。

16. The batch composition of claim 1 comprising 15 μm DP₅₀≤30μm。

17. The batch composition of claim 1, comprising 0.4DP₅₀≤DI₅₀≤0.8DP₅₀。

18. The batch composition of claim 1, comprising 0.4DP₅₀≤DI₅₀≤0.7DP₅₀。

19. The batch composition of claim 1, wherein the pore former spherical particles are non-hydrophilic.

20. The batch composition of claim 1, wherein the pore former spherical particles comprise a non-hydrophilic polymer.

21. The batch composition of claim 20, wherein the non-hydrophilic polymer comprises polypropylene, polyethylene, polystyrene, polycarbonate, PMMA (polymethylmethacrylate), polyurethane, and derivatives and combinations thereof.

22. The batch composition of claim 1, wherein the pore former spherical particles comprise a phase change material.

23. The batch composition of claim 1 wherein the pore former spherical particles comprise a polymer having a MP ≧ 100 ℃, where MP is the melting point of the pore former spherical particles.

24. The batch composition of claim 1 wherein the pore former spherical particles have a pore former particle size distribution comprising DPb ≦ 1.30.

25. The batch composition of claim 1 wherein the pore former spherical particles have a pore former particle size distribution comprising DPb ≦ 1.25.

26. The batch composition of claim 1 wherein the pore former particle size distribution of the pore former spherical particles comprises (DP)₉₀-DP₁₀)≤20μm。

27. The batch composition of claim 1 wherein the pore former particle size distribution of the pore former spherical particles comprises (DP)₉₀-DP₁₀)≤15μm。

28. The batch composition of claim 1, wherein the pore former spherical particles comprise from 5 to 35 wt% by additional addition, relative to the total weight of inorganic materials in the batch composition.

29. The batch composition of claim 1, wherein the pre-reacted inorganic spherical particles comprise spray-dried spherical particles.

30. The batch composition of claim 1, comprising a weight of 28 wt% LV < 50 wt% relative to the inorganic materials of the batch mixture by additional addition, wherein LV is the liquid vehicle.

31. The batch assembly of claim 1, wherein the batch composition comprises a weight of 22 wt% LV < 35 wt% with respect to inorganic materials of the batch composition by additional addition, wherein LV is the liquid vehicle and the pore former spherical particles are non-hydrophilic.

32. The batch composition of claim 1, comprising an organic binder that is a combination of hydroxyethyl methylcellulose binder and hydroxypropyl methylcellulose binder.

33. The batch composition of claim 1, wherein the pre-reacted inorganic particles comprise one or more crystalline phases.

34. The batch composition of claim 33, wherein the pre-reacted inorganic particles comprise one or more glass phases.

35. The batch composition of claim 33, wherein the one or more crystalline phases comprise at least one of: (i) aluminum titanate, (ii) feldspar, (iii) mullite, (iv) titania, (v) magnesia, (vi) alumina, (vii) magnesium dititanate, (viii) silicon carbide, (ix) pseudobrookite, (x) cordierite, (xi) cordierite, magnesia, aluminum titanate composite, and (xii) combinations thereof.

36. The batch composition of claim 33, wherein the pre-reacted inorganic spherical particles comprise a first crystalline phase comprising primarily a solid solution of aluminum titanate and magnesium dititanate, and a second crystalline phase comprising cordierite.

37. The batch composition of claim 33, wherein the pre-reacted inorganic spherical particles comprise: a pseudobrookite crystalline phase comprising primarily alumina, magnesia, and titania, a second crystalline phase comprising cordierite, and a third crystalline phase comprising mullite.

38. The batch composition of claim 1, comprising τ Y/β greater than 4.0.

39. The batch composition of claim 1, comprising τ Y/β greater than 4.5.

40. A method of manufacturing a honeycomb body, the method comprising:

mixing a batch composition comprising pre-reacted inorganic spherical particles, fine inorganic particles, organic binder, pore former spherical particles, and liquid vehicle to form a paste,

wherein the pre-reacted inorganic spherical particles have the following pre-reacted particle size distribution:

10μm≤DI₅₀less than or equal to 50 mu m, and

DIb is less than or equal to 2.0; and is

Wherein the pore-forming agent spherical particles have the following pore-forming agent particle size distribution:

0.40DP₅₀≤DI₅₀≤0.90DP₅₀and is and

DPb ≦ 1.32, and

wherein DI₅₀Median particle diameter, DP, of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles₅₀Is the median particle diameter of the pore-forming agent particle size distribution of the pore-forming agent spherical particles, DIb is the width factor of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles, and DPb is the width factor of the pore-forming agent particle size distribution of the pore-forming agent spherical particles; and is

Wherein the fine inorganic particles account for less than 20 wt% based on the total weight of the pre-reacted inorganic spherical particles and have a median particle diameter of less than 5 μm; and

the paste is formed into a wet green honeycomb body.

41. The method of claim 40, comprising τ Y/β greater than 4.0.

42. The method of claim 40, comprising τ Y/β greater than 4.5.

43. The method of manufacturing of claim 40, the method comprising:

drying the wet green honeycomb body to form a dried green honeycomb body; and

the dried green honeycomb body is fired to form a porous ceramic honeycomb body.

Technical Field

The present disclosure relates to batch composition mixtures comprising pre-reacted inorganic particles and methods of making honeycomb bodies therefrom.

Background

Ceramic honeycombs containing cordierite, silicon carbide, and aluminum titanate have been used in catalytic converters and particulate filters for diesel and gasoline engine exhaust aftertreatment.

These ceramic honeycombs can be made by extruding a plasticized batch composition of inorganic and organic materials and a Liquid Vehicle (LV), such as deionized water, through an extrusion die of an extruder.

In some batch compositions, pre-reacted spherical particles are used in the batch. However, these batch compositions may suffer from certain performance problems.

Disclosure of Invention

Exemplary embodiments of the present disclosure relate to a batch composition. The batch composition comprises pre-reacted inorganic spherical particles having a pre-reacted particle size distribution, wherein:

10μm≤DI₅₀less than or equal to 50 μm, and

DIb is less than or equal to 2.0; and

a pore former spherical particle having a pore former particle size distribution, wherein:

0.40DP₅₀≤DI₅₀≤0.90DP₅₀and is and

DPb ≦ 1.32, and

wherein DI₅₀Median particle diameter, DP, of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles₅₀Is the median particle diameter of the pore-forming agent particle size distribution of the pore-forming agent spherical particles, DIb is the width factor of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles, and DPb is the width factor of the pore-forming agent particle size distribution of the pore-forming agent spherical particles.

In some embodiments, the batch composition comprises less than 20% fine inorganic particles based on the total weight of the pre-reacted inorganic spherical particles, wherein the fine inorganic particles have a median diameter of less than 5 μm.

In some embodiments, the batch composition comprises less than 10% fine inorganic particles based on the total weight of the pre-reacted inorganic spherical particles, wherein the fine inorganic particles have a median diameter of less than 5 μm.

In some embodiments, the batch composition comprises less than 5% fine inorganic particles based on the total weight of the pre-reacted inorganic spherical particles, wherein the fine inorganic particles have a median diameter of less than 5 μm.

In some embodiments, the AR of the pre-reacted inorganic spherical particles_AverageLess than or equal to 1.2, wherein, AR_AverageIs the average aspect ratio, which is defined as the largest width dimension divided by the smallest width dimension of the pre-reacted inorganic spherical particles on average.

In some embodiments, the AR of the pore former spherical particles_Average≤1.1，

In some embodiments, the AR is_AverageIs the average aspect ratio, which is defined as the largest width dimension divided by the smallest width dimension of the spherical particles of the pore former, on average.

In some embodiments, the batch composition comprises 20 μm DI₅₀≤50μm。

In some embodiments, the batch composition comprises 20 μm DI₅₀≤40μm。

In some embodiments, the batch composition comprises DI₉₀≤85μm。

In some embodiments, the batch composition comprises DI₉₀≤65μm。

In some embodiments, the batch composition comprises 45 μm DI₉₀≤85μm。

In some embodiments, the batch composition comprises DI₁₀≥8μm。

In some embodiments, the batch composition comprises 8 μm DI₁₀≤35μm。

In some embodiments, the batch composition comprises (DI)₉₀-DI₁₀)≤55μm。

In some embodiments, the batch composition comprises 15 μm ≦ (DI)₉₀-DI₁₀)≤55μm。

In some embodiments, the batch composition comprises 15 μm DP₅₀≤30μm。

In some embodiments, the batch composition comprises 0.4DP₅₀≤DI₅₀≤0.8DP₅₀。

In some embodiments, the batch composition comprises 0.4DP₅₀≤DI₅₀≤0.7DP₅₀。

In some embodiments, the pore former spherical particles are non-hydrophilic.

In some embodiments, the pore former spherical particles comprise a non-hydrophilic polymer.

In some embodiments, the non-hydrophilic polymer includes polypropylene, polyethylene, polystyrene, polycarbonate, PMMA (polymethylmethacrylate), polyurethane, and derivatives and combinations thereof.

In some embodiments, the pore former spherical particles comprise a phase change material.

In some embodiments, the pore former spherical particles comprise a polymer having a MP ≧ 100 ℃, where MP is the melting point of the pore former spherical particles.

In some embodiments, the pore-former particle size distribution of the pore-former spherical particles comprises DPb ≦ 1.30.

In some embodiments, the pore-former particle size distribution of the pore-former spherical particles comprises DPb ≦ 1.25.

In some embodiments, the pore-former particle size distribution of the pore-former spherical particles comprises (DP)₉₀-DP₁₀)≤20μm。

In some embodiments, the pore-former particle size distribution of the pore-former spherical particles comprises (DP)₉₀-DP₁₀)≤15μm。

In some embodiments, the pore former spherical particles comprise 5 to 35 weight percent, relative to the total weight of inorganic materials in the batch composition, by additional addition.

In some embodiments, the pre-reacted inorganic spherical particles comprise spray-dried spherical particles.

In some embodiments, the batch composition comprises a weight of 28 wt% LV < 50 wt% with respect to the inorganic materials of the batch mixture by additional additions, wherein LV is the liquid vehicle.

In some embodiments, the batch composition comprises a weight of 22 wt% LV 35 wt% with respect to the inorganic materials of the batch composition by additional addition, wherein LV is the liquid vehicle and the pore-former spherical particles are non-hydrophilic.

In some embodiments, the batch composition comprises an organic binder that is a combination of hydroxyethyl methylcellulose binder and hydroxypropyl methylcellulose binder.

In some embodiments, the pre-reacted inorganic particles comprise one or more crystalline phases.

In some embodiments, the pre-reacted inorganic particles comprise one or more glassy phases.

In some embodiments, the one or more crystalline phases comprise at least one of: (i) aluminum titanate, (ii) feldspar, (iii) mullite, (iv) titania, (v) magnesia, (vi) alumina, (vii) magnesium dititanate, (viii) silicon carbide, (ix) pseudobrookite, (x) cordierite, (xi) cordierite, magnesia, aluminum titanate composite, and (xii) combinations thereof.

In some embodiments, the pre-reacted inorganic spherical particles comprise a first crystalline phase comprising primarily a solid solution of aluminum titanate and magnesium dititanate, and a second crystalline phase comprising cordierite.

In some embodiments, the pre-reacted inorganic spherical particles comprise: a pseudobrookite crystalline phase comprising primarily alumina, magnesia, and titania, a second crystalline phase comprising cordierite, and a third crystalline phase comprising mullite.

In some embodiments, the batch composition comprises τ Y/β greater than 4.0.

In some embodiments, the batch composition comprises τ Y/β greater than 4.5.

Exemplary embodiments of the present disclosure also relate to methods of manufacturing honeycomb bodies. The method comprises the following steps: mixing a batch composition to form a paste, the batch composition comprising pre-reacted inorganic spherical particles, fine inorganic particles, an organic binder, pore former spherical particles, and a liquid vehicle, wherein the pre-reacted inorganic spherical particles have a pre-reacted particle size distribution of:

10μm≤DI₅₀less than or equal to 50 μm, and

DIb is less than or equal to 2.0; and is

Wherein the pore-forming agent spherical particles have the following pore-forming agent particle size distribution:

0.40DP₅₀≤DI₅₀≤0.90DP₅₀and are and

DPb ≦ 1.32, and

wherein DI₅₀Median particle diameter, DP, of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles₅₀Is the median particle diameter of the pore-forming agent particle size distribution of the pore-forming agent spherical particles, DIb is the width factor of the pre-reacted particle size distribution of the pre-reacted inorganic spherical particles, and DPb is the width factor of the pore-forming agent particle size distribution of the pore-forming agent spherical particles; and wherein the fine inorganic particles account for less than 20 wt% based on the total weight of the pre-reacted inorganic spherical particles and have a median particle diameter of less than 5 μm. The method further comprises the following steps: the paste is formed into a wet green honeycomb body.

In some embodiments, the method comprises τ Y/β greater than 4.0.

In some embodiments, the method comprises a τ Y/β greater than 4.5.

In some embodiments, the method further comprises: 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.

Additional features of the 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 only and are intended to provide further explanation of the invention as claimed.

Drawings

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 exemplary embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

Fig. 1 illustrates a schematic view of a honeycomb body of an exemplary embodiment of the present disclosure.

Fig. 2 illustrates a planar side view of a spherical particle showing the maximum width dimension W1 and the minimum width dimension W2 (shown deformed for illustrative purposes) of the spherical particle.

Fig. 3 illustrates a partial cross-sectional side view schematic of an extruder configured to produce a green honeycomb body using one or more embodiments of the batch composition.

Fig. 4A and 4B illustrate graphs of particle size distributions of respective examples of pre-reacted inorganic spherical particles according to embodiments.

FIG. 5 illustrates a graph of the particle size distribution of the polymeric pore former spherical particles according to exemplary embodiments of the present disclosure.

Fig. 6 illustrates a flow chart of a method for manufacturing a porous ceramic honeycomb using pre-reacted inorganic spherical particles and pore former spherical particles according to an exemplary embodiment of the present disclosure.

FIG. 7A illustrates P of an exemplary embodiment of a comparative batch composition comprising reactive particles at various velocities V and for different capillary lengths L_{General assembly}(psi) vs. number of samples.

FIG. 7B illustrates P of an exemplary embodiment of a batch composition comprising pre-reacted inorganic spherical particles at various velocities V and for different capillary lengths L_{General assembly}(psi) vs. number of samples.

FIG. 8A illustrates P of one exemplary embodiment of a comparative batch composition comprising reactive particles extruded through different capillary lengths L of a capillary rheometer_{General assembly}(psi) vs. V (inches/second).

FIG. 8B illustrates P of an exemplary embodiment of a batch composition comprising pre-reacted inorganic spherical particles extruded through different capillary lengths L of a capillary rheometer_{General assembly}(psi) vs. V (inches/second)。

Fig. 9 illustrates a cross-sectional side view of a capillary rheometer configured to test the rheological properties of a batch composition, according to an embodiment.

Fig. 10 illustrates an exemplary graph of entry pressure pe (psi) versus velocity (in inches per second) for an exemplary embodiment of a batch composition comprising pre-reacted inorganic spherical particles.

Detailed Description

The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the disclosure are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth and described herein. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and will fully convey the scope of the disclosure. In the drawings, the overall dimensions and relative dimensions are not drawn to scale. Like reference numerals in the drawings denote like elements throughout the present disclosure.

In the manufacture of ceramic honeycomb articles, a plasticized batch composition comprising inorganic and organic materials and a Liquid Vehicle (LV) (e.g., water) is extruded through an extrusion die of an extruder. One goal is to extrude plasticized batch materials at as fast a feed rate as possible while providing a high quality green body, as the feed rate is at least somewhat related to the ultimate manufacturing cost of the ceramic honeycomb. Specifically, in honeycomb manufacture, a plasticized batch composition is extruded through an extrusion die having a plurality of fine, intersecting die slots formed therein. Upon exiting the extrusion die, the extruded green honeycomb body should exhibit excellent overall dimensional control, a limited amount of sagging or deformation under its own weight, excellent bonding between individual cell walls, excellent cell shape (e.g., square or other desired shape), excellent wall formation (e.g., minimal waviness), and no wall tearing. Minimizing shrinkage of the honeycomb body when dried is also a desirable goal.

Conventional batch compositions for making ceramic honeycombs involve mixing and/or milling inorganic powders wherein the resulting combined inorganic particle distribution has a fairly broad particle size distribution. The inorganic powder may include a source of titanium dioxide, a source of alumina, a source of silica, a source of magnesium oxide, and the like. These inorganic particles are mixed with an organic binder (e.g., a cellulose-based binder), possibly with a lubricant and LV (e.g., deionized water), and in some cases with a pore former material to form a plasticized batch composition. The plasticized batch composition is then extruded through an extrusion die of an extruder to form a green body (e.g., a green honeycomb body). The green honeycomb body is then dried and fired by conventional methods to produce a porous ceramic honeycomb body.

In other embodiments, sinter-bonded or reaction-bonded pre-reacted inorganic spherical particles have been proposed for use in batch compositions suitable for the manufacture of porous ceramic honeycombs, for example, as described in WO 2014/189741.

The use of conventional pore former material combinations of starch and graphite in such batch compositions comprising pre-reacted inorganic spherical particles may have certain deficiencies (e.g., tearing) that are believed to be due to the micro-segregation of water in the batch composition. "pre-reacted inorganic spherical particles" are defined herein as inorganic particles formed into spheres (e.g., by spray drying) that have been at least partially reacted (e.g., by firing or by calcining) to include a desired ceramic crystalline phase composition prior to being provided to the batch composition.

However, as discovered by the present inventors, when inorganic spherical particles are used in combination with certain spherical pore former particles, the surface texture of the green body honeycomb produced by extrusion is very smooth and substantially free of wall defects, such as tears. Additionally, very low levels of pore former material may be required to provide a high porosity ceramic honeycomb. In some embodiments, less LV may be used in the batch composition. Such batch compositions surprisingly provide excellent extrudability as well as relatively high extrusion feed rates.

It is worth noting that during extrusion of the green honeycomb, it is advantageous to use a relatively stiff batch material (having a high τ Y, described fully hereinafter) because this allows for better shape control of the wet green honeycomb, i.e., less wall and/or cell deformation, less tearing and less slumping (geometric sag due to deformation under the weight of the honeycomb itself). The stiffness coefficient "τ Y" is a measure of the stiffness of a particular plasticized batch composition. τ Y is measured and determined as described below. Conventional batches with stiffer batch characteristics can result in higher extrusion pressures and slower feed rates. The addition of LV (e.g., deionized water) to conventional batch compositions may allow for improved feed rates due to lower friction between the batch and the fine die slot surfaces, but this may come at the expense of shape control of the wet and dried green honeycombs, i.e., sag deformation, failure of the walls to bond together, and other defects. The coefficient of friction "β" is a measure of friction and also affects the wall drag, which is the friction of the plasticized batch composition against the die wall surface as the batch composition passes through a slit of defined size. Beta was measured and determined as described below.

Thus, in conventional batch compositions there is a natural tradeoff between the desired high batch stiffness (high τ Y) and low wall friction (low β). Thus, the ratio of the batch stiffness coefficient (τ Y) divided by the friction coefficient (β) can be used to characterize the rheological behavior of the batch composition during extrusion (i.e., τ Y/β). A high τ Y/β ratio is desirable (at a sufficiently high residence time of the batch composition such that the extruded honeycomb substantially retains its shape and does not sag under its own weight), and if achievable, this can enable higher extrusion rates. However, the conventional aluminum titanate batch materials have very low τ Y/β ratios, i.e., in the range of about 1.0 to less than about 1.5. The increase in the ratio τ Y/β is elusive, especially for aluminum titanate-based compositions.

Thus, improvements in batch compositions that can enable higher feed rates while also retaining good shape control and good quality of wet and dried green honeycombs would be considered a significant advance in the honeycomb extrusion art.

In particular, the present inventors have discovered that certain combinations of pre-reacted inorganic spherical particles with organic pore former spherical particles provide improved batch rheology and die extrusion behavior. In particular, improved τ Y/β ratios may be implemented in accordance with one or more embodiments of the present disclosure. In embodiments, when the pre-reacted inorganic spherical particles and pore former spherical particles comprise a relatively narrow particle size distribution along with a median particle size (D50) provided in a defined relationship, the batch composition exhibits excellent extrusion properties and exhibits a high ty/beta ratio while also providing excellent shape control of the extruded green body honeycomb. For example, in some embodiments, a ratio of τ Y/β ≧ 4.0, or even τ Y/β ≧ 4.5 can be achieved. In addition, the properties of the resulting green honeycomb body can include low levels of wall and cell distortion, low tear, smooth wall finish, excellent final dimensional control, low slump levels, and low shrinkage levels.

One or more embodiments of the present disclosure relate to a batch composition that includes pre-reacted inorganic spherical particles in combination with pore former spherical particles. The batch composition may also include small amounts (i.e., less than a defined amount) of fine inorganic binder particles (hereinafter "fines"). The distribution of pre-reacted inorganic spherical particles is selected to include a specifically controlled median particle size (DI)₅₀) And its relatively narrow particle size distribution. The narrowness of the distribution can be defined by DIb, where DIb is the distribution width factor of the pre-reacted inorganic spherical particles. Other forms of characterization of narrowness, e.g. DI, may also be used₉₀-DI₁₀This is further defined herein.

Likewise, the distribution of the spherical particles of the pore former is selected to include a specifically controlled median particle size (DP)₅₀) And its narrow pore former particle size distribution. One measure of the narrowness of the particle distribution is DPb, where DPb is the pore former distribution width factor. Other forms of characterization of the narrowness of the distribution may also be used.

In embodiments, the median particle size (DI) for pre-reacted inorganic spherical particles₅₀) Selected to have a specified size range. More particularly, toControlled median particle size (DI) compared to pre-reacted inorganic spherical particles₅₀) For the median diameter DP of the spherical particles of the pore-forming agent₅₀Chosen so that it is within a particular size range. Specifically, the dimensions are selected to have a particular dimensional relationship represented below wherein the pre-reacted inorganic spherical particles and the pore former spherical particles each further comprise a relatively narrow particle size distribution.

Exemplary embodiments of the present disclosure provide batch compositions useful for the formation of green body articles, such as honeycomb body 100 shown in fig. 1. The honeycomb body 100 includes a plurality of intersecting walls 102 that extend from one end 103 to the other end 105 of the honeycomb body 100. The intersecting walls 102 form a plurality of channels 104 that also extend in parallel relationship from one end to the other. Square cell shapes are shown. However, other cell cross-sectional shapes may be formed, such as rectangular, triangular, hexagonal, circular, or combinations thereof. The honeycomb body 100 (e.g., a green honeycomb body) can be dried and fired to form a porous ceramic honeycomb body comprising porous walls. The intersecting walls 102 of the resulting porous ceramic honeycomb body after firing comprise open and interconnected pores. Any suitable overall cross-sectional size, length, shape (e.g., circular, trilobal, oval, racetrack, etc.) of honeycomb body 100 can be formed from the batch composition.

Referring to fig. 1-10, additional features and characteristics of exemplary embodiments of batch compositions, green body articles (e.g., green honeycomb bodies) made from the batch compositions, and ceramic articles (e.g., porous ceramic honeycomb bodies) produced from the batch compositions are disclosed herein.

More specifically, embodiments of the present disclosure provide batch compositions that include a particular combination of pre-reacted inorganic spherical particles and pore former spherical particles. The combination can provide excellent extrusion rates and batch processability.

Inorganic spherical particles

In an embodiment, the batch composition comprises pre-reacted inorganic spherical particles having a pre-reacted particle size distribution represented by equation 1 below:

10μm≤DI₅₀equation 1 less than or equal to 50 mu m

And may also include a relatively narrow particle size distribution, represented by equation 2 below:

DIb is less than or equal to 2.0 equation 2

Wherein DI₅₀Is the median particle diameter of the particle size distribution of the pre-reacted inorganic spherical particles, and DIb is the distribution width factor of the particle size distribution of the pre-reacted inorganic spherical particles, which is a measure reflecting the relative narrowness of the particle size distribution. The width factor DIb of the particle size distribution of the pre-reacted inorganic spherical particles can be defined by equation 3 shown below:

DIb＝{DI₉₀-DI₁₀}/DI₅₀equation 3

DI₉₀Defined herein as a certain coarse particle diameter of the pre-reacted inorganic spherical particles in the particle size distribution of the pre-reacted inorganic spherical particles, wherein 90% of the pre-reacted inorganic spherical particles in the particle size distribution have a diameter equal to or smaller than the certain coarse particle diameter, i.e. the remaining particles (about 9.9999%) have a larger particle diameter. DI₁₀Defined herein as a certain fine particle diameter of the particles in the particle size distribution of the pre-reacted inorganic spherical particles, wherein 10% of the pre-reacted inorganic spherical particles in the particle size distribution have a particle diameter equal to or smaller than the fine particle diameter, i.e. the remaining particles (about 89.9999%) have a larger particle diameter.

While DIb is one measure of the relative narrowness of the particle size distribution of the pre-reacted inorganic spherical particles, other measures may also be used to characterize the relative narrowness of the particle size distribution of the pre-reacted inorganic particles, e.g., DI₉₀-DI₁₀。

DI₅₀

In some embodiments of the batch composition, the pre-reacted inorganic spherical particles have a particle size distribution wherein 10 μm DI₅₀Less than or equal to 50 μm (including 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm and 50 μm), and further including 1All subranges and subranges between 0 μm and 50 μm, including 10 μm and 50 μm, wherein DI is₅₀Is the median particle diameter of the particle size distribution of the pre-reacted inorganic spherical particles.

In some embodiments, the pre-reacted inorganic spherical particles have DI₅₀Even narrower range particle size distributions. For example, in a further embodiment, the median particle diameter DI of the pre-reacted inorganic spherical particles₅₀Can be 20 μm.ltoreq.DI₅₀DI of 50 μm or less, or even 20 μm or less₅₀Less than or equal to 40 mu m. The pre-reacted inorganic spherical particles may be formed by a spray drying process. In some embodiments, the median particle diameter DI of the pre-reacted inorganic spherical particles₅₀Adjustments may be made during its formation by varying: nozzle type, nozzle tip internal diameter, nozzle rotation rate, nozzle pressure, size and type of fine inorganic particulates, temperature settings, organic binder, dispersant and surfactant types and levels, and solids loading (i.e., solid to liquid ratio) during spray drying when producing green inorganic spherical particles. Spray drying of green spherical particles is disclosed, for example, in U.S. patent No. 2016/0251249.

In other embodiments, the narrowness of the relatively coarse pre-reacted inorganic spherical particles may be enhanced by certain particle processing suitable for removing some portion or portions of the pre-reacted inorganic spherical particles therein. For example, processing such as sieving, winnowing, settling or sedimentation separation may be used to remove coarse and/or fine fractions from the particle size distribution. For example, a coarse fraction in a particle size distribution having a size greater than about 60 microns, and thus particles smaller than about 53 microns, can be removed by passing the powder through a 270 mesh sieve (having a mesh opening of about 53 microns). Other screen sizes may be used to remove other portions from the large particle end of the particle size distribution. Likewise, small portions may be removed and larger particles retained by using a smaller mesh screen. Other separation techniques may also be used.

The green inorganic spherical particles may be formed by: the slurry containing the inorganic material is spray dried and then calcined or fired to produce pre-reacted inorganic spherical particles. Rotary calcination at temperatures of about 1000 ℃ to 1650 ℃, or even about 1200 ℃ to 1600 ℃ may be employed. The specific calcination temperature will depend on the specific composition of the inorganic particles contained in the slurry and the desired phase composition of the pre-reacted inorganic spherical particles. Thus, it will be appreciated that the particle size distribution of the pre-reacted inorganic spherical particles may be engineered and/or pre-processed to conform to the particle size distribution parameters or other even narrower characteristics as expressed in equations 1 and 2 above.

DI₉₀And DI₁₀

In some exemplary embodiments, the distribution of pre-reacted inorganic spherical particles in the batch composition may have DI₉₀85 μm or less, or even DI₉₀75 μm or less, or even DI₉₀65 μm or less, or in some embodiments even DI₉₀Less than or equal to 55 mu m. In some embodiments, the pre-reacted inorganic spherical particles in the batch composition can have a DI of 45 μm ≦ DI₉₀DI of 85 μm or less, or even 45 μm or less₉₀Less than or equal to 65 mu m. These ranges can provide useful porosity ranges and can produce particularly narrow pore size distributions in fired honeycombs useful for highly catalyzed filters for producing relatively low pressure drop, relatively high filtration efficiency and relatively high catalytic activity.

In some exemplary embodiments, the distribution of pre-reacted inorganic spherical particles in the batch composition may have DI₁₀≧ 8 μm, and in some embodiments, DI₁₀Not less than 10 μm. In other embodiments, the distribution of pre-reacted inorganic spherical particles in the batch composition may have DI₁₀Not less than 20 μm, or even DI₁₀Not less than 30 μm. In some batch compositions, the pre-reacted inorganic spherical particles may have a DI within the following range₁₀：8μm≤DI₁₀35 μm or less, or even 10 μm or less DI₁₀≤35μm。

The narrowness of the distribution of the pre-reacted inorganic spherical particles in some batch compositions, for example, can include DI₁₀Not less than 3 μm andDI₉₀a composition with a particle size of less than or equal to 85 mu m. In other batch compositions, the pre-reacted inorganic spherical particles have DI₁₀Not less than 3 μm and DI₉₀A composition with a particle size of less than or equal to 40 mu m. In certain exemplary embodiments, DI may be provided₁₀Not less than 8 μm and DI₉₀A composition with a particle size of less than or equal to 40 mu m.

The narrowness of the pre-reacted inorganic spherical particles can alternatively be determined by the function DI₉₀-DI₁₀And (4) showing. In some embodiments, the distribution of pre-reacted inorganic spherical particles may have DI₉₀-DI₁₀Less than or equal to 55 μm, or even DI₉₀-DI₁₀Less than or equal to 40 μm, or even DI₉₀-DI₁₀Less than or equal to 30 μm, or even DI₉₀-DI₁₀Less than or equal to 20 mu m. In some particularly narrow embodiments of the distribution of pre-reacted inorganic spherical particles, DI₉₀-DI₁₀≤15μm。

In some embodiments, DI₉₀-DI₁₀Can range from 15 μm ≦ DI₉₀-DI₁₀55 μm or less, or in other embodiments, 25 μm or less DI₉₀-DI₁₀Less than or equal to 55 mu m. In some particularly narrow embodiments, DI of the distribution of pre-reacted inorganic spherical particles₉₀-DI₁₀The range may be 30 μm.ltoreq.DI₉₀-DI₁₀≤55μm。

As described above, in some embodiments, the formed green inorganic spherical particles or the calcined or fired pre-reacted inorganic spherical particles may be sized or otherwise classified to remove fine tail portions and/or coarse tail portions, such that the above-described distribution width factors DIb, DI of the particle size distribution of the pre-reacted inorganic spherical particles may be met₁₀、DI₉₀And/or DI₉₀-DI₁₀. The particle sizes specified herein were measured by a Microtrac (macbec) S3500 laser diffractometer.

Table 1 below shows examples of some pre-reacted inorganic spherical particles. Fig. 4A and 4B illustrate some representative particle size distribution plots of pre-reacted inorganic spherical particles formed by spray drying process (SPD). The phase composition of the pre-reacted inorganic spherical particles can be engineered to have any desired phase composition desired in the final honeycomb. For example, the phase composition of pre-reacted inorganic spherical particles may include cordierite, mullite, and aluminum titanate phases (hereinafter "CMAT"). However, other compositions as described herein are also possible. Other suitable methods of forming pre-reacted inorganic spherical particles may include spin-drying, as well as atomizing the slurry to form green inorganic particles, which may then be calcined to form pre-reacted inorganic spherical particles.

TABLE 1 particle size distribution after prereaction

Table 2 below shows about DI₅₀30 μm to about DI₅₀Other exemplary embodiments of spray dried green pellets of 50 μm.

TABLE 2-other exemplary embodiments of Pre-reacted inorganic spherical particles

DI10(μm)	DI50(μm)	DI90(μm)	DIb	DI90-DI50(μm)
					22.73	33.4	51.0	0.85	28.25
28.3	42.6	64.6	0.85	36.30
					34.1	49.4	74.2	0.81	40.10
30.9	46.7	74.3	0.93	43.49
					32.9	49.2	81.6	0.99	48.69
22.8	32.9	49.6	0.82	26.86
					23.7	35.5	54.5	0.87	30.79
29.1	44.9	70.2	0.92	41.10
					27.7	40.3	60.6	0.82	32.88
31.5	48.1	75.5	0.91	43.95
					23.2	34.1	517	0.84	28.55
23.0	33.6	50.6	0.82	27.59
					31.3	45.8	69.4	0.83	38.08
25.0	36.8	55.8	0.84	30.77
					24.5	35.7	537	0.82	29.24
29.2	44.1	66.6	0.85	37.37
					25.2	36.3	53.9	0.79	28.69
25.6	38.4	59.0	0.87	33.40
					29.1	42.4	63.5	0.81	34.35

The fired pre-reacted spherical particle size may be slightly offset from the green spherical particle size. As can be seen from the above, extremely narrow particle size distributions for spherical particles can be achieved, including DIb ≦ 1.0, DIb ≦ 0.95, DIb ≦ 0.90, DIb ≦ 0.85, DIb ≦ 0.80, and in some embodiments, even 0.75 ≦ DIb ≦ 1.0. Similarly, the narrowness of the distribution of the spherical particle sizes may be determined, for example, by D₉₀-D₁₀Wherein, 25 μm. ltoreq. (D)₉₀-D₁₀)≤45μm。

Pore-forming agent spherical particles

The batch composition also includes a distribution of pore former spherical particles having a median particle size, DP, of the pore former particle size distribution₅₀Selected as median particle diameter DI relative to the distribution of the pre-reacted inorganic spherical particles₅₀Within a selected range. Median particle size DP of the spherical particles of the pore-forming agent₅₀Is represented by the relationship shown in equation 4 shown below.

0.4DP₅₀≤DI₅₀≤0.9DP₅₀Equation 4

This size range of the pore former spherical particles can ensure excellent particle packing with the pre-reacted inorganic spherical particles, compared to the size of the pre-reacted inorganic spherical particles. If the size of the pore former spherical particles is too small, the pore former spherical particles will simply fill the stacked pores of the pre-reacted inorganic spherical particles and will not serve as a pore former. If the pore former particle size is greater than DI₅₀Particle packing may be affected and risk loosening during firing, resulting in irregularities and/or possibly large shrinkage, or in the worst case, honeycomb cracking or powdering during firing. Thus, by using a smaller size than DI₅₀The spherical polymeric pore former of (a) retains a dense packing of pre-reacted inorganic spherical particles, which in turn converts to voids/pores without significant shrinkage during firing.

In some embodiments, DP₅₀Can range from 15 μm & lt, DP₅₀Less than or equal to 30 mu m. In other embodimentsIn the formula, a narrower size range of the pore-former spherical particles than the size of the pre-reacted inorganic spherical particles in equation 4 can be represented by the relationships shown in equations 5 and 6 below.

0.4DP₅₀≤DI₅₀≤0.8DP₅₀Equation 5

0.4DP₅₀≤DI₅₀≤0.7DP₅₀Equation 6

An even narrower range may be used, e.g., 0.4DP₅₀≤DI₅₀≤0.6DP₅₀Or 0.4DP₅₀≤DI₅₀≤0.5DP₅₀. The above can result in the following advantages: has a narrow pore size distribution in the final fired honeycomb and can provide a low pressure drop to the particulate filter in the case of a narrow pore size distribution of the particular pores (d50-d10/d 50). In addition, the narrow pore size distribution provides better catalyst utilization during catalyst coating, as well as higher final catalyst utility.

The batch composition may also include a relatively narrow particle size distribution of the pore former spherical particles. In an embodiment, the relative narrowness of the particle size distribution of the pore former spherical particles can be expressed in one aspect by the relationship shown in equation 7 below:

DPb ≦ 1.32 equation 7

Wherein DPb is a distribution width factor of the particle size distribution of the pore-forming agent spherical particles. The distribution width factor DPb of the distribution of the pore-forming agent spherical particles can be defined by equation 8 shown below:

DPb＝{DP₉₀-DP₁₀}/DP₅₀equation 8

DP₉₀Defined as the certain coarse particle diameter of the pore-former spherical particles in the pore-former size distribution, wherein 90% of the pore-former spherical particles in the pore-former size distribution have a diameter equal to or less than the coarse particle diameter, i.e., the remaining particles (about 9.9999%) have a larger diameter. DP₁₀Defined as a certain fine particle diameter of the pore-forming agent spherical particles in the pore-forming agent particle size distribution, wherein the particle diameter of 10% of the pore-forming agent spherical particles in the pore-forming agent particle size distribution is equal to or smaller thanAt this fine particle diameter, i.e., the remaining particles (about 89.9999%), have a larger diameter.

In other embodiments, the narrowness of the particle size distribution of the pore former spherical particles may be represented by equation 9 or equation 10 shown below.

DPb ≤ 1.30 equation 9

DPb ≤ 1.25 equation 10

In other embodiments, the narrowness of the particle size distribution of the spherical particles of the pore former may be determined by DP₉₀-DP₁₀Is shown in (DP)₉₀-DP₁₀) 20 μm or less, or in some embodiments even (DP)₉₀-DP₁₀)≤15μm。

The pore former spherical particles can be provided in any suitable amount in the batch composition depending on the porosity to be achieved in the porous ceramic honeycomb body 100. For example, in the batch composition, the pore former spherical particles may be provided in the following amounts: from about 5 wt.% SAT to 40 wt.% SAT, or in some embodiments even from about 10 wt.% SAT to 25 wt.% SAT, wherein SAT is based on the wt.% of the total inorganic matter present in the batch composition. As used herein, "SAT" means additional additions based on the total weight of inorganic materials included in the batch composition.

In some embodiments, the pore former spherical particles in the batch composition may include one or more non-hydrophilic materials. For example, the pore former spherical particles may comprise a non-hydrophilic polymeric material. The non-hydrophilic material is neutral or hydrophobic.

Examples of non-hydrophilic polymers may include polypropylene, polyethylene, polystyrene, polycarbonate, PMMA (polymethylmethacrylate), polyurethane, and derivatives and combinations thereof. In some embodiments, the non-hydrophilic pore former spherical particles in the batch composition may comprise hollow gas bubbles or may be porous. The present inventors have discovered that the use of low hydrophilic (neutral non-hydrophobic) pore former spherical particles as compared to natural potato, pea or corn pore formers translates into batch compositions that contain less LV% of the batch for comparable batch stiffness (β) as compared to compositions containing highly hydrophilic pore formers (e.g., starch). This translates into a batch composition comprising less LV% of the batch for comparable batch stiffness (β) compared to a composition comprising a highly hydrophilic pore former (e.g., starch). This is accompanied by the advantage of providing less time to dry and less shrinkage of the extruded honeycomb upon drying, and thus improved final shape and dimensional control. It may also result in less wall tearing during extrusion.

More specifically, exemplary embodiments of the spherical particles of the pore former may include non-hydrophilic polymer particles having a melting point MP, which may be, for example, MP ≧ 100 ℃, or even MP ≧ 120 ℃. In some embodiments, the pore former spherical particles may comprise a phase change material. A "phase change material" is a substance with a high heat of fusion that melts and solidifies at a certain temperature, capable of storing and releasing large amounts of energy.

Table 3 below shows an example of the particle size distribution of the non-hydrophilic pore former spherical particles. However, other suitable pore former spherical particles having the desired median particle size and narrowness can be used, for example, hydrophilic polymers.

TABLE 3 spherical particle size examples of pore formers

Fig. 5 shows representative exemplary particle size distributions (differential volume% versus particle diameter (microns)) for these types of pore former polymer spherical particles. As will be appreciated, the pore former polymer spherical particles can be produced in any suitable diameter to satisfy the size relationship of the pre-reacted inorganic spherical particles according to, for example, the relationship described in equation 4 herein.

Fines

Additionally, the batch composition may include a small weight percentage of fine inorganic particles ("fines"). Specifically, the batch composition may include fine inorganic particles of less than 20% by weight SAP. The fine inorganic particles ("fines") are relatively small particles in which the particle size distribution of the "fines" is added to the batch composition and may have a median particle diameter of the "fines" distribution of less than 5 μm. As used herein, "SAP" means an additional addition based on the total weight of pre-reacted inorganic spherical Particles (PI) included in the batch composition, which is defined by equation 11 shown below:

fines in% by weight SAP ═ 100 (weight of "fines" weight of PI) x100 equation 11

In other embodiments, the batch composition comprises less than 15% by weight of fine inorganic particles of SAP, wherein the particle size distribution of the "fines" has a median particle diameter of less than 5 μm. In other embodiments, the batch composition comprises less than 10% by weight of fine inorganic particles of SAP, wherein the distribution of "fines" has a median diameter of less than 5 μm, or even less than 7.5% by weight of fine inorganic particles of SAP, wherein the particle size distribution of "fines" has a median diameter of less than 5 μm. The "fines" in the batch composition act as inorganic binders in the batch, forming ceramic interconnects between pre-reacted inorganic spherical particles upon firing. Such fine oxide powders ("fines") have a large surface area/mass and, due to their large surface area, interact strongly with the LV in the batch composition. Most "fines" are hydrophilic and therefore, they tend to "bind" large amounts of LV, thereby reducing LV and particle mobility, which acts to thicken the batch composition and increase friction of the batch composition. More internal friction of the batch composition means more friction through the batch composition passing through the extrusion die. This translates into greater extrusion pressure to push the batch composition through the extrusion die and thus has a low T_{Initiation of}And low extrusion rates. Therefore, it is desirable to minimize fines in the batch composition.

In some embodiments, the "fines" in the batch composition may include a combination of fine talc, fine alumina, and fine silica (e.g., colloidal silica). In further embodiments, both the fine alumina and fine silica particles added to the batch composition each comprise a particle size distribution having a median particle diameter of less than 2 μm. However, "fines" may include any suitable combination of inorganic particles having a median particle diameter of less than 5 μm, and which include sources of silica, alumina and/or magnesia.

In some embodiments, the fine inorganic particles ("fines") in the batch composition may comprise a combination of alumina, talc, and silica particles, each having a particle distribution with a median particle diameter of less than 5 μm.

In other embodiments, the batch composition comprises less than 15% and greater than 3% by weight fine inorganic particles, wherein the distribution of fine inorganic particles has a median particle diameter of less than 5 μm. In other embodiments, the batch composition comprises less than 10% and greater than 3% by weight fine inorganic particles, wherein the distribution of fine inorganic particles has a median particle diameter of less than 5 μm. In some embodiments, the batch composition comprises less than 7.5 wt% and greater than 3 wt% fine inorganic particles, wherein the distribution of fine inorganic particles has a median particle diameter of less than 5 μm.

In some embodiments, the fines in the batch composition comprise alumina particles at about 1 to 5 wt% SAP, talc particles at 1 to 7 wt% SAP, and silica particles at 0.5 to 3 wt% SAP, wherein SAP is an additional addition based on the total weight of pre-reacted inorganic spherical particles included in the batch composition. In some embodiments, the fine inorganic particles may comprise very fine alumina particles having a particle distribution with a median particle diameter of less than about 1 μm, or in some embodiments even less than 0.7 μm. In some embodiments, the fine inorganic particles may comprise 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 comprise fine silica particles having a particle distribution with a median 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).

When "fines" comprising alumina, talc and silica are used in combination as the inorganic binder, the composition is intended to form cordierite and some glass phase in the region between pre-reacted inorganic spherical particles after firing. To facilitate glass formation in the final porous ceramic honeycomb, low levels of glass-forming agents, such as ceria, yttria, calcia, other alkaline earths, rare earths, or bases, may be added to the batch composition. These glass formers may be provided in the batch composition at a level of 1.0 wt.%, 0.5 wt.%, 0.3 wt.%, or less, based on SAP.

When only alumina and talc are used in combination as fine inorganic binder ("fines") and possibly glass former, the composition is intended to form mullite, cordierite and glass phases in the regions between pre-reacted inorganic spherical particles after firing.

When alumina, talc, silica and titania are used in combination as the inorganic binder, the composition is intended to form cordierite, pseudobrookite and some secondary glass phase in the regions between pre-reacted inorganic spherical particles after firing.

As the inventors have discovered, even small amounts of very fine titanium dioxide powders with d50<1 μm in the batch composition can produce very sticky slip layers and drastically reduce the τ Y/β ratio to values close to the τ Y/β ratio of conventional, non-pre-reacted batches. Thus, the inorganic binder in the batch composition may be substantially free of titanium dioxide due to the design for fast extrusion rates. Substantially free of titanium dioxide means less than 0.3% SAP of titanium dioxide. However, in some embodiments, the titanium dioxide in the "fines" may be used as a process lever to adjust the extrusion properties of the batch composition.

AR_Average

In an embodiment, the pre-reacted inorganic spherical particles 203 and the pore former spherical particles 206 are spherical. As used herein, spherical means having a spherical shape. The spherical shape is defined as having an average aspect ratio AR as shown in FIG. 2_AverageDefined as the maximum width dimension W1 of a spherical particle divided by the averageThe shortest width dimension W2, as shown in equation 12 below:

AR_averageEquation 12W 1/W2

In particular, in one or more embodiments, the pore former spherical particles 206 may have an average aspect ratio AR_AverageWherein, AR_Average≤1.1。AR_AverageSome spherical particles of polymers ≦ 1.1 are commercially available. Similarly, the pre-reacted inorganic spherical particles 203 may have an average aspect ratio AR_AverageWherein, AR_Average≤1.2。

To achieve this AR of pre-reacted inorganic spherical particles 203_Average≦ 1.2, the pre-reacted inorganic spherical particles 203 may be formed by a spray drying process, for example, as fully described in WO 2016/138192. In some embodiments, the pre-reacted inorganic spherical particles 203 may be formed by rotary calcining the spray-dried green particles at a suitable temperature to retain the spherical shape, depending on the composition of the pre-reacted inorganic spherical particles 203, for example at a temperature of about 1,000 ℃ to 1,650 ℃, or even about 1200 ℃ to 1,600 ℃.

Organic binder

The batch composition may include an organic binder. For example, the organic binder may be a hydrophobically modified cellulose ether binder. In some embodiments, the hydrophobically modified cellulose ether binder can be, but is not limited to, methyl cellulose, ethyl hydroxyethyl cellulose, hydroxybutyl methyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxybutyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethyl cellulose, mixtures thereof, and the like. Methylcellulose and/or methylcellulose derivatives are particularly suitable as organic binders in batch compositions using methylcellulose and hydroxypropylmethylcellulose. The source of the cellulose ether is commercially available from the Dow chemical company: (Chemical Co.)) METHOCEL^TMA cellulosic product.

Some embodiments of the batch composition, such as those disclosed in table 7 below, may include a combination of methylcellulose and hydroxypropyl methylcellulose. Other combinations of cellulose ether binders may include cellulose ethers having different molecular weights. Alternatively, the combination of cellulose ethers may include cellulose ethers having different hydrophobic groups, cellulose ethers having different concentrations of the same hydrophobic groups, or other combinations of cellulose ethers. As a non-limiting example, the different hydrophobic groups may be hydroxyethyl or hydroxypropyl.

The organic binder may be provided in the batch composition in an amount of about 4.0 wt.% SAT to 8.0 wt.% SAT, where SAT is based on the wt.% of the total inorganic materials (e.g., pre-reacted inorganic spherical particles plus inorganic "fines") present in the batch composition. In some embodiments, the organic binder may be a combination of a hydroxyethyl methylcellulose binder and a hydroxypropyl methylcellulose binder, with a hydroxyethyl methylcellulose binder of about 2.0 to 6.0 wt.% SAT, and a hydroxypropyl methylcellulose binder of about 1.0 to 3.0 wt.% SAT. Other suitable combinations of organic binders may also be used.

LV％

In one or more embodiments, the batch composition comprises LV, e.g., deionized water, provided as the liquid vehicle percentage LV%. The LV% in the batch composition is substantially higher than the amounts used in conventional batches, but a significantly higher batch stiffness (high τ Y, e.g., τ Y ≧ 8.0) can be retained.

LV can be added to the batch composition in a weight percent of 22% ≦ LV% ≦ 50% by additional addition (SAT) relative to the total amount of inorganic materials present in the batch composition (e.g., the sum of pre-reacted inorganic spherical particles and "fines"). In exemplary embodiments where the pore former spherical particles include a non-hydrophilic material (e.g., a non-hydrophilic polymer), the LV is present in a lower amount, e.g., 22% LV. ltoreq. 35% by weight, relative to the inorganic materials of the batch composition, by additional addition (SAT). Thus, natural less tearing and higher batch stiffness (e.g., higher β) can be provided as compared to hydrophilic pore former spherical particles. Thus, pore former spherical particles that are not hydrophilic, or at least less hydrophilic than starch, are advantageous for use in batch compositions.

In use, LV provides a medium in which the organic binder is dissolved and thus provides plasticity to the batch composition and wetting of the fine inorganic particles ("fines") and pre-reacted inorganic spherical particles therein. LV may be a water-based liquid, which is typically water or a water-miscible solvent. In one embodiment, the LV is deionized water, but other solvents, such as alcohols, may also be used.

In some embodiments, the LV% in the batch composition is LV%. gtoreq.22% (SAT), or even LV%. gtoreq.25%, or even LV%. gtoreq.30%, or even LV%. gtoreq.35%, or even LV%. gtoreq.40%, or even LV%. gtoreq.45%, based on the total weight of the inorganic particles (pre-reacted inorganic spherical particles plus "fines") present in the batch composition, with additional addition of (SAT) by weight.

Remarkably, as discovered by the present inventors, wet green honeycomb bodies 100 (fig. 1) formed from the batch compositions disclosed herein, even though they contain such extremely high liquid vehicle incorporation (LV% ≧ 22% (SAT), LV% ≧ 25% (SAT), or even LV% ≧ 30% (SAT)), include extremely low wall drag, as evidenced by low β, but surprisingly also include extremely high batch stiffness, as evidenced by relatively high τ Y, and therefore maintain excellent shape control.

In particular, as shown in table 8 below, high τ Y/β ratios are also achieved by using the batch compositions described herein. Ratios τ Y/β ≧ 3.0, τ Y/β ≧ 3.5, τ Y/β ≧ 4.0 or even τ Y/β ≧ 4.5 can be achieved using the batch compositions described herein. In some embodiments, τ Y ≧ 10.0, τ Y ≧ 14.0, or even τ Y ≧ 18.0 can be achieved. In some embodiments, β ≦ 5.0, β ≦ 4.0, or even β ≦ 3.5 may be achieved.

In exemplary embodiments where the pore former spherical particles 206 are non-hydrophilic, relatively low β (e.g., β ≦ 5.0) and relatively high τ Y (τ Y ≧ 8.0) may be achieved to retain excellent shape control, but lower LV% (e.g., LV ≦ 35% (SAT), LV ≦ 30% (SAT), or even LV ≦ 25% (SAT)) may be used, thus providing lower loss on drying and an equivalent level of inherently higher batch stiffness of the hydrophilic pore former.

Determination of τ Y and β

A homogeneous ceramic batch composition constituting a paste was made from a mixture of batch inorganics (pre-reacted inorganic spherical particles, and "fines"), pore former particles, organic binder, LV (e.g., deionized water), and optional lubricant by high shear mixing the ingredients in a Brabender mixer (commercially available Brabender Plastograph EC 3.8kW,200NM/150 minutes, equipped with model 359 mixer). In some embodiments, the stiffness of the paste is measured with a penetrometer to ensure proper paste consistency. A commercially available penetrometer ESM-301E motorized test stand with a digital dynamometer was used.

The paste flow properties of the batch compositions were measured using a commercially available two-hole capillary rheometer (hereinafter "capillary rheometer") having an instrumented piston and multiple capillary lengths. Batch stiffness and wall drag can be measured simultaneously on a capillary rheometer. Fig. 9 shows an example of a capillary rheometer 900.

The capillary rheometer 900 used comprises a number of cylindrical barrels 902 of diameter D of 16mm and several capillaries 908 of different lengths L with small circular bores and with a capillary diameter D of 1 mm. The capillary length L is in the range of 0mm to 16mm, especially 0mm (in practice 0.25mm for practical reasons), 4mm, 10mm and 16 mm. The disc pistons 904 are mounted for translational movement in the barrel 902 when a force F is applied to the pistons 904, for example, by applying the force F to a cross member 906 interconnected with each piston 904. After mixing as described above, the batch composition 910 that makes up the paste is placed and extruded from barrel 902 of capillary rheometer 900 into and through capillary 908 at various force F levels, thereby creating different velocities V. On capillary rheometer 900Representative pressure drop P_{General assembly}By measuring the pressure P supplied to the piston 904_{General assembly}And velocity Vp, the piston 904 contacts and causes the batch composition 910 to be extruded through the capillary 908. The total pressure P for each die (e.g., die showing long and zero lengths) is determined by pressure sensor 912_{General assembly}The pressure sensor 912 measures the pressure P exerted on the batch composition 910 contained in the barrel 902_{General assembly}。

The velocity V of the batch composition 910 in the capillary 908 is related to the piston velocity Vp by a representative area ratio according to equation 13 below, equation 13:

V＝Vp(D²/d²) Equation 13

The piston velocity Vp may 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 containing the barrel 902. The total pressure P may be provided to a suitable controller 916_{General assembly}And piston velocity Vp, the controller 916 including a suitable processor and memory configured to perform calculations sufficient to yield as output calculated values capable of producing the τ Y and β values of the batch composition.

Table 4 below shows representative raw data from an exemplary capillary velocity scan test illustrating four capillaries 908 of different lengths L (L being 16mm, 10mm, 4mm and 0.25mm) and capillary diameters d of 1 mm. For each length L, the push rate of the piston 904 ("plunger") and the extrusion rate out of the capillary ("noodle") are provided, as well as the total pressure P_{General assembly}。

TABLE 4 velocities (V and Vp) and Total pressures (P) for various capillary lengths (0.25mm to 16mm)_{General assembly}) And (4) relationship.

When the shortest capillary 908 having a length L of 0.25mm (or about 0mm) is used for extrusion, the batch composition 910 needs to adapt its shape from the relatively larger diameter D (16mm) of the barrel 902 to the woolThe relatively small diameter d (1mm) of the tubule 908. A pressure drop P across the capillary 908 ("about zero capillary")_{General assembly}Corresponding to the batch stiffness through the pressure required for the batch composition to shrink from a 16mm barrel geometry to a 1mm capillary 908. The use of "about zero capillary" can be indicated and can be used to determine the entrance loss component because its short length (about L-0) minimizes the wall drag component and thus can be effectively ignored. The use of longer capillaries (e.g., 16mm long capillaries) results in a wall drag component due to friction/drag along the length L of the wall of the capillary 908 and a stiffening of the batch composition due to its shape change, i.e., an in-loss component. Thus, the measured pressure drop P as a function of the velocity V_{General assembly}An entrance loss component Pe and a wall drag component Pw may be included, which are separable as will be apparent.

At 10 different speeds V [ effective velocity (V) from 0 mm/sec to 4 inches/sec (101.6 mm/sec) ]]The batch compositions were tested for different lengths of capillary tubing (0mm to 16mm) having a capillary length L using a capillary velocity scan test at a constant temperature of about 25 ℃. The extrusion velocity V (noodles) through the capillary 908 is increased stepwise to successively higher velocities V, and when a steady-state velocity V is reached, a representative total pressure drop (P) per step is recorded via sensor 912_{General assembly}). This original P will be for each length L of the capillary 908_{General assembly}And velocity V data are provided to controller 916, stored in memory and further calculated as described herein to calculate τ Y and β for each measured batch composition table 5 below shows exemplary values for one batch composition.

TABLE 5L/d, noodle speeds V, Tw, Pe-average and Pe intercept

As shown in fig. 10, the graph of the entry pressure pe (psi) versus velocity V (in/sec) shows and illustrates the non-linearity of the entry pressure loss as a function of the velocity V provided by the zero length (0.25 in) capillary 908.

A representative example of raw data output from a capillary velocity sweep test using four different capillaries and 10 speeds is shown in fig. 7B, which illustrates test values for a batch composition comprising pre-reacted inorganic spherical particles in multiple stages and multiple curves (each corresponding to one capillary length) (where a larger L value illustrates a higher pressure). Fig. 7A shows a representative conventional reactive batch composition, wherein fig. 7A and 7B are both set to the same dimensions to show a relatively large total pressure difference (psi) between the conventional batch composition and the batch composition of an exemplary embodiment comprising pre-reacted inorganic spherical particles using the same test procedures. The raw data may be converted into a pressure versus velocity map using any suitable software program. Fig. 8A and 8B show pressure and velocity plots of a conventional (reactive) Cordierite Mullite Aluminum Titanate (CMAT) reactive batch composition (fig. 8A) versus a spray dried pre-reacted CMAT batch composition (fig. 8B) of some embodiments.

As mentioned above, the total measured pressure drop P_{General assembly}Equal to the entry pressure Pe plus the wall drag contribution Pw, and can be represented by the relationship:

P_{general assembly}＝Pe+Pw

A number of models have been developed that relate the geometric shrinkage of batch composition 910 in capillary rheometer 900 from D to D and the pressure drop through capillary 908 to the batch rheology. The capillary characteristics include capillary diameter d, capillary length L, and some constants that contain aspects related to capillary material and capillary surface roughness, but these constants do not change for a given capillary 908 of a given length L and diameter d. The test methods described herein are used to determine batch rheological characteristics, including τ Y (yield stress) and β (wall drag coefficient), which are unique parameters that define the rheological properties of the various batch compositions described herein.

The bo-bridqiwatt (Benbow-Bridgwater) model is used to describe the wall drag force Pw as a function of capillary length L, capillary diameter d, velocity V, wall drag coefficient β (beta) and wall velocity index m [ see literature: benbow, J.Bridgwater, Paste flow and extrusion, Oxley, Oxford university Press, 1993 and J.J.Benbow, E.W.Oxley, J.Bridgwater "The extrusion mechanics of The Paste-The effect of The Paste formulation on The extrusion parameters"; science (Chemical engineering science) 53,2151 (1987). The model characterizes the wall drag force Pw as the following equation 14:

Pw＝{4L/d}[βV^m]equation 14

Wherein:

l is the capillary length

d is the capillary diameter

Beta (beta) is the wall drag coefficient

m is wall velocity index

V is paste velocity at the wall

But the shear stress Tw at the wall is as shown in equation 15 below:

Tw＝βV^mequation 15

Thus, the wall drag pressure component can be expressed as the following equation 16:

pw ═ 4L/d) Tw equation 16

The natural logarithm of shear stress (ln (tw)) is plotted against the natural logarithm of velocity (ln (v)). From this plotted data, the term β can be found as the y-intercept of the ln (tw) and ln (v) plots, and m is the slope of this line. The slope m is determined within the length data of 0 inch/sec to 4 inch/sec. Outliers were ignored and the test was performed multiple times and the results were averaged for each batch composition.

The inlet pressure Pe can be approximated by equation 17 below:

Pe＝2{τY+kVⁿ{ Ln (D/D) } equation 17

Suppose P_{General assembly}The model defines a total pressure P as shown in equation 18 below:

P_{general assembly}＝2{τY+kVⁿ}{Ln(D/d)}+{4L/d}[βV^m]Equation 18

Wherein:

τ Y is the yield stress of the batch composition

k is the consistency index

n is the body velocity index

D is the diameter of the extruder barrel

d is the capillary diameter

L is the capillary length

Beta (beta) is the wall drag coefficient

m is wall velocity index

V is paste velocity at the wall

The values of τ Y, k and n can be found from the measured data by three-parameter curve fitting using a solver, such as the solver provided in Excel or any other iterative solver, to minimize the difference between the measured and calculated parameters. The values of τ Y and β (beta) are parameters used herein to characterize the extrusion rheology of the batch compositions described herein, and are calculated as described above. Based on this measured raw data, controller 916 calculates τ Y and β.

Lubricant/surfactant

The batch composition may also include a lubricant, for example, an oil type lubricant. Non-limiting examples of oil-based lubricants include tall oil, light mineral oil, corn oil, high molecular weight polybutenes, polyol esters, blends of light mineral oil and wax emulsions, blends of paraffin wax in corn oil, combinations of the foregoing, and the like. The amount of lubricant may be from about 0.5 wt% SAT to about 5 wt% SAT. In an exemplary embodiment, the oil lubricant may be tall oil, which is present in the batch composition from about 0.5 wt.% SAT to about 2.5 wt.% SAT.

Further, the batch composition may include a surfactant, particularly a cordierite-forming batch composition. A non-limiting example of a surfactant that can be used in the batch composition is C₈To C₂₂Fatty acids and/or derivatives thereof. An additional surfactant component that may be used with these fatty acids is C₈To C₂₂Fatty acid ester, C₈To C₂₂Fatty alcohols, and combinations thereof. Examples of the inventionThe surfactant is stearic acid, lauric acid, myristic acid, oleic acid, linoleic acid, palmitoleic acid, derivatives thereof, stearic acid in combination with ammonium lauryl sulfate, combinations of any of the foregoing, and the like. The amount of surfactant in the batch composition may generally range from about 0.25 wt% SAT to about 2 wt% SAT.

Phase composition

More specifically, the pre-reacted inorganic spherical particles include particles that have been pre-fired to include a desired crystalline phase composition prior to addition to the batch composition. The porous ceramic honeycomb produced with the pre-reacted particles may have an engineered particle size distribution and may also have an inorganic phase composition. The resulting fired porous ceramic honeycomb body can be characterized by the crystalline phases contained in the solid matter, and the morphology can be characterized by the shape of the matter and the shape of the pores in the ceramic article. For example, but not by way of limitation, the pre-reacted inorganic spherical particles may include one or more phase compositions. In many embodiments, the composition of at least two phases, e.g., a major phase and a minor or minor phase, is provided. Optionally, the pre-reacted particles may comprise more than one secondary phase or secondary phase.

Exemplary batch compositions

Tables 6 and 7 below show examples of batch compositions comprising certain pre-reacted inorganic spherical particles, pore former spherical particles, and "fines". Table 8 shows the rheological properties. The amount and type of "fines" that may be present in the batch composition are discussed above. In the illustrated embodiment, the phase composition of pre-reacted inorganic spherical particles comprises CMAT and includes a main phase of a solid solution of aluminum titanate and magnesium dititanate, a second phase of cordierite, some mullite, and also a glass phase. However, it should be apparent that other crystalline phase compositions of pre-reacted inorganic spherical particles may also be made.

TABLE 6 CMAT batch composition examples

TABLE 7 Binder, Lubricant, and LV%

TABLE 8 rheological Properties of exemplary batch compositions

The above embodiments include several different sizes of spherical particles of the pore former. Pore former 1 includes DP₅₀Non-hydrophilic polymeric pore former spherical particles at 25.8 μm, and the pore former 2 included DP₅₀Spherical particles of a non-hydrophilic polymeric pore former of 17.1 μm. However, other spherical pore former particles within the size range set forth in equations 4, 5, and 6 above may be used. Further, other weight percentages of SAT may be used depending on the desired porosity in the porous ceramic article (e.g., porous ceramic honeycomb).

The ceramic product produced

Porous ceramic articles (e.g., porous honeycombs) produced from drying and firing green articles (e.g., green honeycombs) made using the batch compositions can include any desired final ceramic composition. For example, the final phase composition of the ceramic article may include an aluminum titanate-based composition, such as an aluminum titanate solid solution (pseudobrookite) as the primary phase (greater than 50 vol%), as well as other phases, such as cordierite, feldspar, mullite, spinel, alumina, rutile, or similar oxides, as secondary and/or additional phases. In other embodiments, the final ceramic composition of the porous ceramic article may include cordierite, or other oxides or non-oxidesCeramics, including metals, intermetallics, mullite, Alumina (AI)₂O₃) Zircon, alkali and alkaline earth aluminosilicates, spinel, perovskite, zirconia, ceria, Silica (SiO)₂) Silicon nitride (Si)₃N₄) Silicon aluminum oxynitride (SiAlON) and zeolites.

Porous ceramic articles formed from batch compositions comprising a combination of pre-reacted spherical particles and pore former spherical particles of exemplary embodiments of the present disclosure may be used to manufacture Diesel Particulate Filters (DPFs), Gasoline Particulate Filters (GPFs), partial filters, catalyst supports, catalyst substrates, and combined substrates and particulate filter devices. Porous ceramic articles made from batch compositions having pre-reacted inorganic spherical particles may exhibit relatively large pore sizes and high porosity, good strength, and a low Coefficient of Thermal Expansion (CTE), which enables low clean pressure drop and low pressure drop at high washcoat and catalyst loadings. Accordingly, exemplary embodiments of the present disclosure can integrate high Selective Catalytic Reduction (SCR) catalyst loading and/or high NO removal while providing low pressure drop, high filtration efficiency, and excellent thermal shock resistance_xCatalyst efficiency.

Production of honeycomb bodies

Exemplary embodiments of the present disclosure also provide methods of making honeycomb 100 (fig. 1) by using batch compositions that include a combination of pre-reacted inorganic spherical particles, pore former spherical particles provided in the defined relative sizes described herein, and "fines". In the manufacture of such honeycomb bodies 100, the batch composition (as described herein) may be considered a non-ideal mixture that may be extruded through an extruder 300 as shown in fig. 3. The extruder 300 includes an extrusion die 308 having an array of fine, intersecting slits formed in a desired channel shape. Any suitable cell shape may be used, such as square, rectangular, triangular, hexagonal, etc. The dry batch composition of pre-reacted inorganic spherical particles 203, "fines" and pore former spherical particles 206 is combined with an organic binder, a Liquid Vehicle (LV), possibly an oil type lubricant, and possibly a surfactant, and plasticized by mixing and/or milling these components to produce an at least partially plasticized batch. The at least partially plasticized batch is then fed into an extruder 300, such as a twin screw extruder. As used herein, "plasticized" means the properties of a batch mixture that includes LV (e.g., deionized water) and possibly lubricants and surfactants, and that has been mixed and/or milled to have a paste consistency.

Plasticization may be initiated by initially mixing/grinding the batch composition by any suitable mixing device or combination of mixing devices, for example, with a Muller mill, a screw mixer, a double arm mixer, or a plow blade paddle mixer, among others. LV may be added to hydrate the pre-reacted inorganic spherical particles, "fines," pore former spherical particles, organic binder, and lubricant and/or surfactant to wet-out the organic binder and pre-reacted inorganic spherical particles and pore former spherical particles and form a partially plasticized batch composition.

The plasticized batch composition can be configured as a mass 310 that can be fed intermittently into the extruder 300, or as a continuous or semi-continuous supply stream of relatively small amounts of material, such as a small mass or even particles or streams of partially plasticized batch composition. The plasticized batch composition 312, in a suitable form and consistency, after mixing and/or grinding, can be supplied to the extruder 300. Further, while an extrusion process is described herein, the batch composition may alternatively be suitably formed into a green honeycomb body 100 from a plasticized batch composition by other suitable forming processes, for example, by uniaxial or isostatic pressing, injection molding, and the like.

Referring again to fig. 3, a partially plasticized batch composition 312 can be formed into a green honeycomb body 100G by providing it to the extruder 300 and extruding it from the extruder 300. Extrusion may be performed using any suitable type of extruder 300 that provides a suitable amount of shear to batch composition 312. For example, a hydraulic ram extruder, a two-stage degassing single auger, a single screw extruder, a twin screw extruder, or the like may be used. Other types of extruders may also be used.

In more detail, the extruder 300 may include a screw section that includes one or more extrusion screws 314 (two shown) that may rotate within an extruder barrel 316. The one or more extrusion screws 314 may be driven by a motor 320 at the inlet end of the extruder barrel 316. In a twin screw embodiment, the extruder 300 may include two side-by-side extrusion screws 314. Extruder barrel 316 can be equipped with an inlet port 324 configured for introduction of batch composition 312 for further plasticization. An optional mixing plate 326 may be positioned downstream of the screw section and upstream of the extrusion die 308, and may be contained within a barrel 328, the barrel 328 being mounted on the outlet end of the extruder barrel 316. After the screw section, a mixing plate 326 may be used to further mix, homogenize, and plasticize the batch composition 312.

Also disposed within barrel 328 is a filter screen 330 and a filter screen support 332, each of which is located upstream of extrusion die 308 with respect to the direction of flow (shown as directional arrows) of batch composition 312 pumped by extrusion screw 314. Filter screen 330 is mounted against filter screen support 332 to form a filter assembly configured to remove large particles, accumulations, or debris that may clog or prevent flow through extrusion die 308. In some embodiments, filter screen support 332 is formed having a plurality of openings and/or slots therein. Extrusion die 308 includes a plurality of upstream feed holes and a plurality of downstream intersecting fine slits. The plasticized batch composition 312 flows through a plurality of intersecting fine slots of the extrusion die 308, which forms a matrix of intersecting walls 102 and channels 104 in the green honeycomb body 100G. Examples of extrusion dies and manufacturing processes are described, for example, in US 2017/0120498; US 2008/0124423; and US8,591,287. Other suitable extrusion dies may also be used.

Thus, during operation of the extruder 300, the plasticized batch composition 312 is pumped from the extruder barrel 316 by the one or more extrusion screws 314, then through the filter screen 330, the filter screen support 332, and the optional mixer plate 326 and finally exits the extrusion die 308 of the extruder 300 as a green honeycomb body 100G. The green honeycomb body 100G can be transversely cut into lengths by a cutting apparatus 334 that includes a cutting device, such as a wire. Once cut, the green honeycomb body 100G can be received and supported on a tray 336, such as the tray disclosed in US 2015/0273727. Other suitable tray configurations may be used.

The wet green honeycomb body 100G can then be dried by transporting the wet green honeycomb body to a dryer (not shown) on a tray 336 via a conveyor (not shown), and dried by any suitable drying process, such as oven drying, microwave drying, RF drying, combinations thereof, and the like, to form a dried green honeycomb body. Suitable drying processes and apparatus are described, for example, in US9,429,361; US9,335,093; US8,729,436; US8,481,900; US 7,596,885; US 5,406,058; and 2014/0327186.

Firing

The dried green honeycomb body can be fired according to known firing techniques to form a porous ceramic honeycomb body 100, as shown in fig. 1. For example, the dried green honeycomb body can be fired in a gas or electric kiln under conditions effective to convert the dried green honeycomb body into a ceramic article (e.g., porous ceramic honeycomb body 100). The firing conditions in terms of temperature and time depend, for example, on the specific batch composition and dimensions and geometry of the dried green honeycomb body.

In some embodiments, firing conditions effective to convert the dried green honeycomb body into the porous ceramic honeycomb body 100 can include: depending on size, shape and composition, the dried green honeycomb bodies are heated in a furnace and in an air atmosphere to a maximum soaking temperature at a heating rate of 50 ℃/hour to 300 ℃/hour, for example, in the range of 1000 ℃ to 1600 ℃, depending on the batch composition used. The maximum soaking temperature may be maintained for a holding time of between about 1 and 30 hours sufficient to convert the dried green honeycomb body into the porous ceramic honeycomb body 100. The cooling may then be performed at a rate that is sufficiently slow (e.g., a cooling rate of about 10 ℃/hr to about 160 ℃/hr) such that the porous ceramic honeycomb body 100 does not thermally shock and crack. The firing time also depends on factors such as the type and amount of pre-reacted inorganic spherical particles, inorganic "fines," organic binders, and pore former spherical particles in the batch composition, and the nature of the firing equipment, but the total firing time may be, for example, from about 20 hours to about 80 hours.

For batch compositions used primarily to form aluminum titanate, the maximum firing temperature is from about 1,320 ℃ to about 1,550 ℃, and the holding time at these temperatures is from about 1 hour to about 6 hours.

For batch compositions used primarily to form aluminum titanate-mullite, the maximum firing temperature is from about 1,350 ℃ to about 1,450 ℃, and the hold time at these temperatures is from about 1 hour to about 6 hours.

For batch compositions used primarily to form cordierite-mullite, aluminum titanate (CMAT), the maximum firing temperature is from about 1,300 ℃ to about 1,380 ℃, and the hold time at this temperature is from about 1 hour to about 6 hours.

For batch compositions used primarily to form mullite, the maximum firing temperature is from about 1400 ℃ to about 1600 ℃, and the hold time at that temperature is from about 1 hour to about 6 hours.

The highest firing temperature for the cordierite-mullite-forming mixture to yield cordierite-mullite is from about 1375 ℃ to about 1425 ℃ and the hold time at that temperature is from about 1 hour to about 6 hours.

For example, in compositions used primarily for cordierite formation, the maximum firing temperature is from about 1300 ℃ to about 1450 ℃, and the hold time at this temperature is from about 1 hour to about 6 hours.

Suitable examples of firing processes and equipment are described, for example, in US9,452,578; US9,221,192; US8,454,887; US8,187,525; US6,551,628; US6,325,963; US6,287,509; US6,207,101; US6,089,860; US6,048,199; and US6,027,684. Other suitable firing processes and equipment may also be used.

Accordingly, one or more embodiments of the present disclosure provide a method of manufacturing a honeycomb body. As shown in fig. 6, one exemplary embodiment of a method 600 includes: at 602, a batch composition comprising pre-reacted inorganic spherical particles, fine inorganic particles ("fines"), organic binder, pore former spherical particles, and Liquid Vehicle (LV) is mixed to form a paste. In the batch composition, the pre-reacted inorganic spherical particles have the following pre-reacted particle size distribution:

10μm≤DI₅₀not more than 50 μm, and DIb not more than 2.0, and

the pore former spherical particles had the following pore former particle size distribution:

0.40DP₅₀≤DI₅₀≤0.90DP₅₀and DPb is less than or equal to 1.32, and

the fine inorganic particles ("fines") comprise less than 20% by weight, based on the total weight of the pre-reacted inorganic spherical particles, and have a median particle diameter of less than 5 μm.

The method 600 further comprises: at 604, the paste is shaped to form a wet green honeycomb (e.g., green honeycomb 100G), for example, by extrusion through an extrusion die or other suitable shaping process, and then, at 606, the wet green honeycomb is dried to form a dried green honeycomb; and in 608, firing the dried green honeycomb body to form a porous ceramic honeycomb body (e.g., porous ceramic honeycomb body 100).

Spray drying process

According to exemplary embodiments of the present disclosure, the fine raw material powder and soluble components may be mixed with water, as well as any organic binders, dispersants, surfactants, and/or defoamers, in a slurry. The slurry may then be suspended in a carrier gas and atomized at the top of the spray dryer. The above parameters can be varied to adjust particle size and particle size distribution. For example, fine raw material powders, such as particles smaller than 1 μm, or soluble components may be used.

Solid, green spray-dried inorganic spherical particles of different median particle size, particle size distribution, and composition may be produced according to exemplary embodiments of the present disclosure by using different spray-dryer settings and different starting materials. The green particles may be dense or contain varying levels of porosity, ranging from almost fully dense to porous.

According to exemplary embodiments, alpha alumina or boehmite may be used as the alumina source, a colloidal silica suspension may be used as the silica source, and fine magnesia may be used as the magnesia source of the raw material. Other inorganic materials, such as strontium carbonate, calcium carbonate, and lanthanum carbonate, may be jet milled to a particle size of less than 1 μm and may optionally be added to the slurry. For example, lanthanum acetate, boron oxide, and other sintering aids may be added to the slurry in the form of an aqueous solution. Other sintering aids may include lanthanum oxide, cerium oxide, yttrium oxide, zirconium oxide, boron oxide, alkali metal oxides, and the like.

Exemplary embodiments of combinations of inorganic raw material powders spray dried to form green spherical particles include alumina (fine alpha alumina or boehmite) with 1.5% to 15% fine silica; alumina with various sintering additives such as B, Mg, Y, Fe, etc.; alumina-silica mixtures with various sintering additives, such as B, Mg, La, Y, Fe, etc.; an Aluminum Titanate (AT) composition; a feldspar composition; an aluminum titanate and feldspar composition; CMAT compositions and cordierite compositions, and the like.

According to some exemplary embodiments, the spray dried green particles may be pre-fired at different temperatures and/or for different firing times in a box or tube furnace, in a crucible, in a sintering box or on a settler, or in a rotary calciner. The conditions for static firing of the dried green alumina and silica based particles may include a maximum firing temperature of 1,200 ℃ to 1,600 ℃ and a hold time of 1 hour to 15 hours. Conditions for statically firing the green particles of the AT-based composition may include a temperature of 1300 ℃ to 1600 ℃.

In a static setting, the green particles may sinter together at high temperatures and long holding times, and thus may break apart before further use (e.g., as an ingredient of a batch composition). In some embodiments, sieving or low energy milling may be used to break up the loosely sintered aggregates to form pre-reacted inorganic spherical particles.

The rotation of the green particles during pre-firing avoids sintering together and may better retain the spherical shape. An industrial rotary calciner may be used to sinter the particles. For example, the rotary calcination conditions for alumina and silica based green particles may include, for example, 1,000 ℃ to 1,650 ℃. As another example, the rotary calcination conditions for the AT spray-dried particles can include, for example, 1,000 deg.C to 1,400 deg.C. Other suitable calcination temperatures may be used.

Porous ceramic honeycomb body

Various shapes and channel geometries of the final ceramic honeycomb body 100 produced from a batch composition of pre-reacted inorganic spherical particles, pore former spherical particles, and "fines" can be provided. For example, the cell geometry of the porous ceramic honeycomb body 100 can have, for example, about 100cpsi (15.5 cells/cm) to 1,200cpsi (186 cells/cm). Further, the porous ceramic honeycomb body 100 may include a transverse wall thickness of about 0.008 inches (0.20mm) to 0.03 inches (0.76mm), for example. Various combinations of cell density and wall thickness can be produced using the batch composition, including 300 cells per square inch (cpsi) and a wall thickness of 0.014 inches, which is conventionally described as an 300/14 cell structure. Other fired cell structures suitable as honeycomb filters or catalyst substrates may be used, for example, 300/10, 400/14, 600/9.

According to exemplary embodiments of the present disclosure, the porosity of the porous ceramic article may be greater than 30%, greater than 40%, greater than 50%, or even greater than 60%, depending on the amount of pore former spherical particles used in the batch composition. In some embodiments, the porous ceramic honeycomb body 100 may have a median pore diameter (d)₅₀) Wherein d is₅₀≧ 10 μm, e.g., or even d₅₀D is more than or equal to 12 mu m, or even 10 mu m₅₀Not less than 30 μm. The porous ceramic article may have a coefficient of thermal expansion of less than 20xl 0' at room temperature (25 deg.C) to 800 deg.C "⁷K"¹E.g. less than 15xl0"⁷K-¹Or even less than 10xl0"⁷K. Porosity, median pore diameter and pore size distribution by Autopore using software from microphone instruments (Micromeritics)^TMIV 9500 porosimetry.

Reference throughout this specification to example embodiments, and similar language throughout this specification may, but do not necessarily, refer to the same embodiment. Furthermore, the described features, structures, or characteristics of the subject matter described herein with reference to any one embodiment may be used or combined in any suitable manner in other described embodiments. In the description, numerous specific details are provided, such as examples of structures, processes, batch compositions, articles, etc., to provide a thorough understanding of the subject embodiments. One skilled in the relevant art will recognize, however, that the subject matter may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.

The flowcharts and method diagrams described above are generally presented as logical flow diagrams. As such, the depicted order and labeled steps are indicative of representative embodiments. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the method illustrated in the schematic. Additionally, the format and symbols employed are provided to explain the logical steps of the diagram and are understood not to limit the scope of the method illustrated by the diagram. Although various arrow types and line types may be employed in the diagram, they are understood not to limit the scope of the corresponding method. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the method. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.