阅读说明：本技术 对多孔陶瓷体进行底漆厚度控制 (Primer thickness control for porous ceramic bodies ) 是由 M·布莱比 K·M·科克兰 C·P·戴格勒 D.亨利 B·C·刘易斯 正木英树 K·R· 于 2020-04-13 设计创作，主要内容包括：经烧制的陶瓷制品包括在经烧制的陶瓷体的一部分上的丝网印刷的底漆层。底漆层的厚度小于25微米。机器可读码被激光标记到丝网印刷的底漆层上。还提供了对陶瓷制品进行标记的方法。(The fired ceramic article includes a screen printed primer layer on a portion of the fired ceramic body. The primer layer has a thickness of less than 25 microns. The machine readable code is laser marked onto the screen printed primer layer. Methods of marking ceramic articles are also provided.)

1. A fired ceramic article, comprising:

a screen printed primer layer on a portion of the fired ceramic body, wherein the primer layer has a thickness of less than 25 microns; and

a machine readable code laser marked onto the screen printed primer layer.

2. The fired ceramic article of claim 1, wherein the fired ceramic article is porous and the primer layer penetrates the porous ceramic body to a depth of at least 10 microns.

3. The fired ceramic article of any of claims 1-2, wherein, prior to drying, the primer layer comprises TiO₂Pigment, binder, high boiling point solvent and thickener.

4. The fired ceramic article of any of claims 1-3, wherein, after drying, the primer layer comprises TiO₂A pigment.

5. The fired ceramic article of any of claims 1-4, wherein the machine-readable code comprises traceable information.

6. The fired ceramic article of any of claims 1-5, wherein the thickness of the white primer layer is substantially uniform.

7. The fired ceramic article of any of claims 1-6, wherein the laser depth exceeds the thickness of the primer.

8. The fired ceramic article of any of claims 1-7, wherein the primer layer has a thickness greater than 0 and less than or equal to about 22 microns.

9. The fired ceramic article of any of claims 1-8, wherein the white primer layer is substantially non-spalling.

10. The fired ceramic article of any of claims 1-9, wherein the white primer layer is substantially non-cracking.

11. A wall-flow filter comprising the fired ceramic article of any of claims 1-10.

12. A label, comprising:

(a) a primer layer, wherein the primer layer is screen printed and the primer layer has a thickness greater than 0 and less than or equal to about 25 micrometers; and

(b) the laser marks a machine readable code on the primer layer.

13. A method of marking a ceramic article, the method comprising the steps of:

(a) screen printing a primer layer having a thickness greater than zero and less than 25 micrometers onto a portion of the fired ceramic article;

(b) drying the primer layer; and

(c) laser marking a machine readable code on the dried primer layer.

14. The method of claim 13, wherein the fired ceramic article is porous and the primer layer penetrates the porous fired ceramic article by at least 10 microns.

15. The method of any one of claims 13-14, wherein in step (a), the primer layer comprises TiO₂Pigment, binder, high boiling point solvent and thickener.

16. The method of any one of claims 13-15, wherein in step (a), the primer layer has a thickness greater than 0 and less than or equal to about 22 micrometers.

17. The method of any of claims 13-16, wherein the thickness of the primer layer is substantially uniform.

18. The method of any of claims 13-17, wherein the primer layer is substantially free of cracking.

19. The method of any one of claims 13-18, wherein the machine-readable code contains traceable information.

20. The method of any one of claims 13-19, wherein in step (c), a machine readable code is marked to the porous fired ceramic article.

Technical Field

Embodiments described herein relate generally to methods for manufacturing a porous ceramic body, and more particularly to methods of controlling the thickness of a primer when applying a primer coating to a porous ceramic body.

Background

Bar codes (e.g., having a sequence of variable black lines on a contrasting background), datamatrix codes (e.g., having an array of interconnected blocks on a contrasting background), and other machine-readable codes are used in a variety of industries to enable information (e.g., processing and production information) to be stored directly on and/or in association with a product or article, and to be retrieved by a corresponding scanner or device configured to read the code.

For example, the manufacture of porous ceramic honeycombs or articles (e.g., for use as catalytic converter substrates or particulate filters) includes applying a data-bearing indicia containing a machine-readable code to the ceramic body.

There is a need for a cost-effective and efficient method and system for applying data-bearing indicia and machine-readable codes during the manufacture of porous ceramic honeycomb bodies.

Disclosure of Invention

Honeycombs manufactured for the catalytic converter substrate and filter industry can benefit from data-bearing indicia (e.g., machine-readable codes) printed on each honeycomb that can correlate information about each honeycomb with each honeycomb. The present disclosure addresses the performance requirements of materials used to create the necessary contrast between the background and foreground colors of a code to enable the code to be machine-readable. In the embodiments disclosed herein, a white primer layer is first applied to the outer layer of the honeycomb and then a code in a darker contrasting color is applied over the primer, for example, by laser combustion. The creation of code according to embodiments disclosed herein includes: a white background primer was applied by screen printing. The use of screen printing to apply a primer layer to a porous ceramic honeycomb body advantageously enables high processing speeds, including drying, code handling and inspection, while providing a code with excellent readability.

In one aspect, a fired ceramic body is provided. The cast ceramic body includes a screen printed primer layer on a portion of the fired ceramic body, wherein the primer layer has a thickness of less than 25 microns; and a machine readable code laser marked on the screen printed primer layer.

In some embodiments, the fired ceramic article is porous and the primer layer penetrates the porous ceramic body to a depth of at least 10 microns. In some embodiments, prior to drying, the primer layer comprises TiO₂Pigment, binder, high boiling point solvent and thickener. In some embodiments, after drying, the primer layer comprises TiO₂A pigment. In some embodiments, the machine-readable code contains traceable information.

In some embodiments, the thickness of the white primer layer is substantially uniform. In some embodiments, the laser depth exceeds the primer thickness. In some embodiments, the primer layer has a thickness greater than 0 and less than or equal to about 22 micrometers. In some embodiments, the white primer layer does not substantially flake off. In some embodiments, the white primer layer is substantially free of cracks. In some embodiments, a wall-flow filter is provided that includes a ceramic body disclosed herein.

In another aspect, a label is provided that includes (a) a primer layer, wherein the primer layer is screen printed and has a thickness greater than 0 and less than or equal to 25 micrometers; and (b) a machine readable code laser marked onto the primer layer.

In another aspect, there is provided a method of marking a ceramic article, the method comprising the steps of: (a) screen printing a primer layer having a thickness greater than 0 and less than 25 micrometers onto a portion of the fired ceramic article; (b) drying the primer layer, and (c) laser marking a machine-readable code on the dried primer layer.

In some embodiments, the fired ceramic article is porous and the primer layer penetrates the fired porous ceramic article by at least 10 microns. In some embodiments, in step (a), the primer layer comprises TiO₂Pigment, binder, high boiling point solvent and thickener. In some embodiments, in step (a), the primer layer has a thickness greater than 0 and less than or equal to about 22 microns. In some embodiments, the thickness of the primer layer is substantially uniform. In some embodiments, the primer layer is substantially free of cracks. In some embodiments, the machine-readable code contains traceable information. In some embodiments, in step (c), a machine-readable code is marked to the fired porous ceramic article.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure. The drawings, together with the description, further serve to explain the principles of the disclosed embodiments and to enable a person skilled in the pertinent art to make and use the disclosed embodiments. These drawings are intended to be illustrative and not limiting. While the present disclosure is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the present disclosure to these particular embodiments. In the drawings, like reference numbers can indicate identical or functionally similar elements.

Fig. 1 shows the primer thickness and subsurface penetration for each substrate (ceramic article) in the examples.

Fig. 2 shows a SEM of the embodiment of fig. 1.

Fig. 3 shows the aluminum cup test results of the examples.

Fig. 4A-4C show SEM of substrates 1, 2, and 3 with a primer layer that was screen printed using an 380/31 master screen.

Fig. 5A-5F show side-by-side SEM comparisons after screen printing with 180 mesh and 380 mesh screens on substrate 3.

Fig. 6 shows the penetration of the binder into the code.

Fig. 7A-7C illustrate the effect of thickness on cracking of the primer layer.

Fig. 8 shows an SEM of the screen printed primer on substrate 1 of comparative example D.

Fig. 9 shows a boxplot of primer thickness on substrate 3 for example 6 using 305/34, 380/31, and 420/27 mesh screens.

Detailed Description

The present invention will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings. References to "one embodiment," "an example embodiment," "some embodiments," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

Defining: "thickness" as used herein with respect to applying the primer to the surface layer of the ceramic body refers to the distance the primer is present above the outer surface of the surface layer of the ceramic body. For a cylinder, thickness refers to the radial dimension of the primer layer measured outwardly from the outer surface of the cylinder.

As used herein with respect to the size of the primer layer, "depth" refers to the distance the primer has penetrated into the surface layer (and/or wall) of the ceramic body. For a cylinder, the depth of penetration of the primer into the substrate refers to the radial distance of penetration of the primer into the surface layer and/or wall of the cylinder.

As used herein, "laser depth" refers to the distance that the laser can penetrate the thickness of the primer and fuse the primer to the surface layer of the ceramic body.

Examples of ceramic batch mixtures that form cordierite that may be used in practicing the present embodiments are disclosed in the following commonly assigned U.S. patent nos.: 3,885,977; 4,950,628, respectively; 5,183,608, respectively; 5,258,150; 6,210,626, respectively; 6,368,992, respectively; 6,432,856, respectively; 6,506,336, respectively; 6,773,657, respectively; 6,864,198; 7,141,089 and 7,179,316, all of which are incorporated herein by reference in their entirety. Cordierite bodies are formed from inorganic materials including high purity clays, silica, alumina and magnesia, which may be supplied in the form of talc, kaolin, alumina and amorphous silica powders, and may contain other materials as indicated in the cited prior art. The powders are mixed in proportions suitable for forming cordierite bodies as described in the prior art. In addition to cordierite, other porous ceramic materials, such as aluminum titanate, may also be used.

The batch of ceramic precursors can be dry blended with a temporary binder (e.g., a methylcellulose material) to form a dry batch. The ingredients can be compounded by mixing (e.g., in a mill or plough blade mixer). A suitable liquid vehicle, such as water, can be added, along with a plasticizer or lubricant, and milled to form a plasticized batch. When water is used as the solvent, the water hydrates the binder and the powder particles. If desired, surfactants and/or lubricants may then be added to the mixture to wet the binder and powder particles. The plasticized batch is then formed into a honeycomb green body, for example, by extrusion through a die, as described in commonly assigned U.S. patent No. 5,205,991, which is incorporated herein by reference in its entirety.

The plasticized batch can include any number of peptizers, binders (e.g., methylcellulose), extrusion aids, lubricants (e.g., sodium stearate), plasticizers, reinforcing agents, and the like to aid in the extrusion process and/or to produce desired structural and pore properties for the intended application. Examples of materials that may be included in the extrusion formulation include, but are not limited to, glass or ceramic fibers or filaments, silicon carbide fibers, cellulose compounds, starch, stearyl alcohol, graphite, stearic acid, oils, fats, and polymers.

The precursor batch may then be plasticized by shearing the wet mixture formed as described above in any suitable mixer in which the batch is to be plasticized, such as, but not limited to, a twin screw extruder/mixer, a screw mixer, a roll mixer, a Littleford (Littleford) mixer, or a double arm mixer, among others. The plasticized batch can also be shaped, for example, by extrusion through a die to form a green body honeycomb, as described in commonly assigned U.S. patent No. 5,205,991, which is incorporated herein by reference in its entirety. The degree of plasticization depends on the concentration of the components (binders, solvents, surfactants, lubricants, and inorganics), the temperature of the components, the amount of work put into the batch, the shear rate, and the extrusion speed. During plasticization, the binder dissolves in the solvent and forms a high viscosity fluid phase. The binder formed is hard because the system is extremely solvent-poor. The surfactant is capable of adhering the binder phase to the powder particles.

When forming a green honeycomb article by extrusion, the extrusion can be performed using a hydraulic ram extruder, or a two-stage vented single-drill extruder or a twin-screw mixer with a die assembly attached to the discharge end. This green wet article body is then dried to form a dried green body. Useful drying techniques include microwave drying, RF drying, infrared heating, forced hot air drying, ambient air drying, and the like, and combinations thereof. The drying may be performed in a humidity and temperature controlled environment. The green article is then fired in a suitable furnace to form the ceramic honeycomb article.

The labeled ceramic honeycombs described in the present disclosure may be used as anti-fouling devices, for example, in the exhaust systems of automobiles, for example, catalytic conversion substrates or particulate filters, such as in gasoline or diesel powered vehicles. Ceramic honeycomb articles used in these applications are formed from a thin-walled matrix of porous ceramic defining a plurality of parallel gas-conducting channels. In ceramic honeycomb articles used as catalytic substrates in gasoline engine automobiles, the gas conducting channels may be open at both ends. A catalytic coating is applied to the outer surface of the wall. Exhaust gas flowing through the channels contacts the catalytic coating on the wall surfaces. These honeycomb articles are known as flow-through substrates.

The filter comprises a honeycomb design having an inlet end and an outlet end and a plurality of cell channels extending from the inlet end to the outlet end, the cell channels having porous walls, wherein some of the total number of cell channels at the inlet end are plugged along a portion of their lengths and the remaining cell channels that are open at the inlet end are plugged along a portion of their lengths at the outlet end, such that engine exhaust gas flowing through the honeycomb cell channels from the inlet end to the outlet end flows into the open cell channels, through the cell channel walls, and out of the structure through the open cell channels at the outlet end.

Generally, the honeycomb cell density ranges from 235 cells/cm²(about 1500 cells/inch)²) To 1 pore channel/cm²(about 6 cells/inch)²). In addition to these, some examples of commonly used honeycombs include, but are not limited to, about 94 cells/cm²(about 600 cells/inch)²) About 62 cells/cm²(about 400 cells/inch)²) Or about 47 cells/cm²(about 300 cells/inch)²) And has about 31 cells/cm²(about 200 cells/inch)²) Those of (a). For about 62 channels/cm²(about 400 cells/inch)²) Typical wall thicknesses are 0.15 mm. The wall thickness ranges from about 0.075mm to about 1.5 mm.

The primer may be white or light colored to allow the code to be easily visualized on the primer. The primer composition may include a light-colored pigment, for example, made of TiO₂A white pigment is provided to provide a relatively dark color on the primer layerFor example, by laser marking. The primer may comprise a solvent, a binder, and a thickener. Examples of the solvent include acetates and alcohols. Examples of binders include silicones, polysiloxanes, polysilsesquioxanes, titanium containing resins, carbosilane resins, and polysilazanes. Thickeners may provide thixotropic/shear thinning behavior. Useful thickeners include fumed silica. The screen printed primer formulation has a high viscosity to allow for accurate placement of the coverslip during the application process and has clean, clear lines. The thixotropic/shear thinning nature of the screen-printed ink keeps the primer on the surface so that after screen printing (e.g., after application of high shear rate) and a short delay, the ink will return to high viscosity. Advantageously, the short delay to restore the initial viscosity causes the ink film to flow slightly after application, remain on the ceramic body, and form a uniform and smooth surface on the ceramic body.

The primer is applied to the ceramic body in liquid form. Screen printing systems may include three main components-a screen, a doctor blade, and an ink-covering strip. The screen has a pattern therein that allows or blocks the transfer of the primer through the screen. The doctor blade then travels over the pattern area to help transfer the primer to the target surface. The ink-covering strip uniformly covers the pattern with fresh material in preparation for the next printing stroke.

Wire mesh useful for practicing the disclosed embodiments is commercially available. Useful mesh sizes include, but are not limited to 230/48, 305/34, 380/31, and 420/27. Preferred mesh sizes are 305/34, 380/31, and 420/27. The top value of the screen size is the wire diameter per linear inch and the bottom value of the screen size is the single wire diameter in microns. The mesh size controls the amount of primer transferred to the ceramic surface, as well as the amount of primer penetrating the porous subsurface.

The inventors have found that the doctor blade angle aids in the screen printing of the primer. The doctor blade angle is the angle between the doctor blade and the portion being screen printed. A small doctor blade angle allows less primer to flow through the screen onto the ceramic body. Highly corrugated ceramic bodies may require different doctor blade tips or doctor blade angles.

According to embodiments disclosed herein, a white primer layer is screen printed onto a portion of the fired ceramic body. In some embodiments, the primer layer has a thickness of less than 25 microns, less than 22 microns, or even less than 20 microns. As described herein, the inventors have found that primer layers having a thickness of less than 25 microns can be used to obtain a primer layer that is substantially free of spalling or cracking. The surface area of the honeycomb coated with the primer layer can be several square inches (e.g., 1-4 inches by 1-4 inches).

The data bearing indicia applied to the priming layer includes a machine readable code or composition, such as a one-dimensional bar code (conveying information through a series of different widths arranged in one-dimensional lines), a two-dimensional matrix code (e.g., an array of dark and light squares or frames), and the like. The machine-readable composition may include a pattern of printed (e.g., relatively darker colored) dots or other portions and unprinted (e.g., relatively lighter colored) portions. The use of different colors for the printed and unprinted portions may serve to increase the optical contrast between the printed and unprinted portions, thereby reducing the likelihood of reading errors. Machine-readable codes include any type of information-bearing pattern having marked and unmarked portions. The use of a two-dimensional matrix code provides a reliable recording of the information contained within the mark, since a large part (e.g. up to 30%) of the mark may appear unreadable without losing information. In addition to machine-readable components, the indicia may include human-readable components, such as alphanumeric data strings, to aid in extracting data when not available to a computer code reader.

The data-bearing indicia may include specific manufacturing information, such as the particular factory and/or kiln that produced the fired ceramic body, the batch, the date and time of manufacture, and/or a unique individual identification code (e.g., using a globally unique identifier system or other coding system where, for some significant time, there are not two identical codes). The unique individual identification code may include a station, line and/or facility that provides a mark, a date, a serial number of the fired ceramic body produced on that date, and the like. The unique identifier may be further encrypted by a suitable encryption code, so that the code information is difficult to reverse engineer except, of course, the manufacturer who owns the encryption code key.

The data of each unique individual identifier assigned to and associated with a single cell may be stored in a relational database during the manufacturing sequence and may be extracted at a later time. In this manner, the sources, materials and processes used to manufacture the honeycomb bodies, as well as the equipment and equipment used to manufacture the honeycomb bodies, as well as the properties, properties and attributes of the honeycomb bodies, can be readily ascertained after manufacture. Thus, any defects or variations in the honeycomb body can be readily correlated to the materials, processes and/or instruments used. Thus, changes may be made in raw materials, processes, etc., if desired, to effect changes in properties or attributes and to reduce the occurrence of such defects in future honeycomb articles.

The unique identifier information may be generated by a computer program that ensures that the code is unique for each individual cell for a long time, e.g., over ten years. This enables the specific honeycomb to be traced back to whatever process it was subjected to during its manufacture, including traceability to the raw materials used, the specific batches and processes employed, the date of manufacture, the specific extruder lines and extrusion dies used, the kiln and firing cycle, the finishing operations employed, etc.

According to one embodiment disclosed herein, a method for applying data-bearing indicia on a honeycomb body comprises: a ceramic body loading step in which the ceramic bodies are joined, held in the proper orientation, and indexed (index) to a material application station. In the screen printing step, a primer is applied to the fired ceramic through a screen or mesh using a doctor blade or other applicator according to the screen printing technique. The ceramic body may then be indexed to a material drying station. In the drying step, the ceramic body may be positioned near the vent or outlet and a drying gas (e.g., hot air) is flowed onto the surface of the ceramic body. The ceramic body may then be indexed to an encoding station, such as a dot matrix encoding station. The honeycomb body may be positioned adjacent to the laser and the laser contacts the primer layer and applies the code to the primer layer by burning a pattern corresponding to the designated code into the primer layer.

According to the method disclosed herein, a laser is used to oxidize the primer solids and fuse them to the ceramic body surface, thereby applying a data-bearing indicia or code to the white primer layer. In one embodiment, the laser is a carbon dioxide laser. Laser marking can be performed immediately after application of the primer layer, and without any intermediate drying or curing step. After laser marking, the ceramic body may be heated to 350 ° -500 ℃ to calcine the primer layer. In some embodiments, the laser depth (the depth at which the laser can penetrate into the primer layer) is greater than the thickness of the primer layer to facilitate adhesion of the laser mark to the primer and adhesion of the primer to the surface layer of the ceramic body. It will be appreciated that the laser depth may be set by varying the laser type and/or power depending on the composition and thickness of the primer. In some embodiments, the laser depth is less than the thickness of the primer layer, but adhesion to the ceramic body surface is achieved by crystallization (caused by the laser energy) of the inorganic compound (e.g., titanium dioxide) in the primer, and this crystallization then adheres to the ceramic body surface. Preferably, the laser depth is approximately as deep as, or greater than, the primer thickness to promote fusing of the primer to the surface layer of the ceramic body and adhesion of the code to the primer.

Embodiments disclosed herein provide a screen printed primer layer wherein the layer has reduced cracking or flaking, provides improved laser processability for the code to readily penetrate the primer layer when burned into and adhering the code to the surface of the ceramic body, increases laser marking speed (thereby increasing throughput and reducing costs), reduces drying time (thereby increasing throughput and reducing costs), and prevents primer adsorption into the cell matrix (penetration of the primer material through the outer skin and into the walls of the honeycomb).

In order to more fully illustrate the embodiments of the present disclosure, the following examples are set forth below.

Examples

In the examples, three different cordierite substrates (honeycombs) commercially available from Corning Incorporated were used. The substrate 1 is made of cordierite and has a porosity of 40% (hereinafter referred to as "substrate 1"). The substrate 2 was made of cordierite, had a more corrugated surface layer having peaks and valleys, and had a porosity of 65% (hereinafter referred to as "substrate 2"). The substrate 3 is made of cordierite and has a porosity of 30% (hereinafter referred to as "substrate 3"). Other porous ceramic bodies may also be employed, as described herein.

The primer layer was screen printed onto substrate 1, substrate 2 and substrate 3. The screen printing process is to screen print a liquid primer onto the corresponding substrate using the indicated screen (indicated in the corresponding table, figure or description), and a doctor blade and ink-covering strip. The primer was dried by ambient air. Comparative examples A-C included those examples that exhibited cracking or spalling, whereas examples 1-4 did not.

In the examples, the primer layer thickness, primer layer depth, and laser depth were measured by scanning electron microscopy ("SEM") conditions described below. The primer patch was cut into three sections consisting of the rightmost section of the primer patch, the leftmost section of the primer patch and the center section. The samples were then inserted into epoxy. Polished cross-sectional samples were prepared. The conductive carbon coating is evaporated onto the sample to reduce charging. The SEM instrument was Jeol JSM-6610LV at 15kV and with 500 Xmagnification. In tables 2-5 below, five measurements were made on the same area of the sample taken.

The examples used the primer compositions listed in table 1 below.

TABLE 1 primer

Comparative example a and example 1: this example illustrates the effect of different screen sizes on the amount of primer transferred to the substrate. Comparative example a used 180/48 wire mesh, and example 1 used 305/34 wire mesh. As shown in fig. 1, the thickness of the primer layer is reported in microns. As shown in fig. 1, the thickness of the primer layer obtained by screen printing using the 180/48 mesh of comparative example a was greater than the thickness of the primer layer obtained by screen printing using the 305/34 mesh of example 1. Similarly, the depth of the serigraphic layer into each substrate resulting from screen printing with the 180/48 mesh was greater than the depth of the serigraphic layer into each substrate resulting from screen printing with the 305/34 mesh.

Fig. 2 shows a SEM corresponding to the results of fig. 1. The porosity of the substrate also affects the thickness of the resulting screen printed primer layer and the depth of the screen printed layer. This SEM compares the difference in primer thickness when applied to substrates with different porosities through two screens of different mesh sizes. Regardless of porosity, the 180/48 mesh of comparative example a deposited a thicker primer layer on the substrate surface than the 305/34 mesh.

An aluminum cup test was performed to demonstrate the relationship between primer thickness and primer cracking. The same size aluminum cup was used for each of samples A, B and C, as shown in fig. 3. The amount of primer added was varied to establish different primer layer thicknesses: sample a was 2 grams, sample B was 1 gram, and sample C was 0.5 gram. The primer was added to the aluminum cup and then dried at 160 ℃ for 15 hours. The thickest layer of sample a showed primer cracking, while the thinner layers of samples B and C showed no primer cracking, as shown in fig. 3. The relationship between primer thickness and primer cracking was demonstrated using an aluminum cup test. Cracking also typically occurs when the primer layer peels off. To maintain the integrity of the primer patch, the primer layer should not crack or flake off.

Example 2: this example illustrates the effect of using the same screen size, substrates of different porosities on the thickness of the primer layer. Fig. 4A shows an SEM of substrate 1 (made of cordierite and having 40% porosity) with a screen printed primer layer using 380/31 screen mesh size. Fig. 4B shows an SEM of substrate 2 (made of cordierite and having a porosity of 65%) with a screen printed primer layer using 380/31 screen sizes. Fig. 4C shows an SEM of substrate 3 (made of cordierite and having a porosity of 30%) with a screen printed primer layer using 380/31 screen sizes. In the case of the lowest porosity substrate, the thickest primer layer is on the substrate, and the thinnest primer layer is on the highest porosity substrate. This is directly related to the depth of adsorption of the primer solvent into the surface layer of the ceramic body and the particle size of the primer solids (larger particle sizes generally prevent the primer from penetrating deeper into the surface layer).

Figure 5 shows a side-by-side SEM comparison of screen printing with a screen of 180/47 and a screen of 380/31 on substrate 3. Fig. 5A is a pre-thermal shock print on a substrate 3 using an 180/47 mesh. Fig. 5B is a cross-sectional view of the primer after thermal shock using an 180/47 mesh on the substrate 3 of fig. 5A. Fig. 5C is the primer surface of fig. 5B after thermal shock. Fig. 5D is a screen printing process performed on the base material 3 in advance using an 380/31 mesh. Fig. 5E is the primer after thermal shock using 380/31 mesh on the substrate 3 of fig. 5D. Fig. 5F is the primer surface of fig. 5E after thermal shock.

Example 3: substrates 1, 2 and 3 were screen printed with 305/34 and 380/31 screens. The primer patch thickness, depth and laser depth in five locations were analyzed using SEM, and the maximum thickness values were reported. The sample is a polished section and the magnification is 500 times.

Tables 2 and 3 below set forth the results for substrate 1. The five measurement locations of substrate 1 screen printed through the 305/34 screen had a primer thickness of 22.2 microns or less. The five measurement locations of substrate 1 screen printed through the 305/34 screen had a maximum primer depth of 23.8 microns to 34.6 microns. The five measurement locations of substrate 1 screen printed through the 305/34 screen had a maximum laser depth of primer of 14.6 microns to 20.2 microns.

The five measurement locations of substrate 1 screen printed through the 380/31 screen had a primer thickness of 16.6 microns or less. The five measured positions of substrate 1 screen printed through the 380/31 screen had a maximum primer depth of 61.4 microns to 79 microns. The five measurement locations of substrate 1 screen printed through the 380/31 screen had a maximum laser depth of primer of 11.8 microns to 17.4 microns.

Tables 4 and 5 below set forth the results for substrate 2. The five measurement locations of the substrate 2 screen printed through the 305/34 screen had a primer thickness of 7 microns or less. The five measured positions of substrate 2 screen printed through the 305/34 screen had a maximum primer depth of 85.4 microns to 149.4 microns. The five measurement locations of the substrate 2 screen printed through the 305/34 screen had a laser depth of primer of 40.2 microns to 45.4 microns. Each position of the substrate 2 screen printed through the 305/34 screen had a laser depth exceeding the corresponding thickness. As noted above, a laser depth at least as deep as the thickness of the primer layer facilitates fusing of the primer to the substrate surface layer and adherence of the code or indicia to the primer layer.

The substrate 2 screen printed through the 380/31 screen had a primer thickness of 12.2 microns or less. The five measured positions of substrate 2 screen printed through the 380/31 screen had a maximum primer depth of 91.4 microns to 109.4 microns. The five measurement locations of the substrate 2 screen printed through the 380/31 screen had a laser depth of the primer of 43.4 microns to 57.8 microns. Each position of the substrate 2 screen printed through the 380/31 screen had a laser depth exceeding the corresponding thickness. As noted above, a laser depth at least as deep as the thickness of the primer layer facilitates fusing of the primer to the substrate surface layer and adherence of the code or indicia to the primer layer.

Table 2-substrate 1: screen printing through 305/34 screen

Table 3-substrate 1: screen printing through 380/31 screen

Table 4-substrate 2: printing screens through 305/34 screens

Table 5-substrate 2: printing screens through 380/31 screens

Comparative example B and example 4: as shown in table 6, the base material 3 of comparative example B, which was screen-printed with 180/37 screen, had a maximum thickness of 25.4 to 37 micrometers and exhibited peeling. In contrast, as shown in table 7, example 4 includes the substrate 3 screen-printed with 380/31 screens, which had a thickness of 14.6 to 22.5 microns, and exhibited no peeling or cracking.

Table 6-substrate 3: printing screens through 180/37 screens

Table 7-substrate 3: printing screens through 380/31 screens

Fig. 6 shows the adhesive penetrating into the surface layer of the substrate. These pictures were taken by fluorescence optical microscopy [ Olympus IX70] and excited by UV light at 350nm, showing binder penetration. The light grey areas are optical adhesives showing adhesive penetration.

Example 5 and comparative example C: for this example, the primer patch was screen printed onto substrate 3 using an 305/34 screen. Fig. 7A, using a 16 x magnification, shows a screen printed primer on substrate 3 prior to firing. Fig. 7B, using an 80 x magnification, shows the substrate 3 with the screen printed primer of fig. 7A. The area labeled "thin primer region" in fig. 7B illustrates the inventive primer thicknesses of 17.054 microns, 18.978 microns, 19.578 microns, and 22.101 microns for example 5. The area labeled "thick primer region" in fig. 7B is comparative example C and illustrates primer thicknesses of 50.136 microns, 54.343 microns, 55.208 microns, and 57.495 microns. Fig. 7C shows the primer of fig. 7B after firing. The inventive primer layer of example 5 having a thickness of 17.054 to 22.101 microns did not crack, while the primer layer of comparative example C having a thickness of 50.136 to 57.405 microns cracked. The inventive primer layer of example 5 having a thickness of 25 microns or less did not crack. Thus, example 5 demonstrates the effect of primer thickness on cracking.

Comparative example D: a primer patch is screen printed onto the substrate 1. Fig. 8 shows an SEM of the screen printed primer on the substrate 1. The primer thickness was 36.6 microns and SEM showed the primer layer spalled. Thus, comparative example D demonstrates the effect of primer thickness on spalling.

Example 6: the primer patches were screen printed on the substrate 3 using 305/34, 380/31, and 420/27 screens to determine the effect of the screens on patch thickness. The doctor blade and the ink-covering strip are used for screen printing. Fig. 9 shows a boxplot of primer thickness on substrate 3 for example 6 using webs of 305/34, 380/31, and 420/27. When using the screen of 305/34, the average thickness difference was higher than when using the screens of 380/31 and 420/27. The difference in primer thickness was not significant for patches made using the 380/31 and 420/27 screens.

Unless otherwise stated, it is not intended that any method described herein be construed as requiring that its steps be performed in a particular order. Thus, where a method claim does not actually recite an order to be followed by its steps or it does not otherwise specifically imply that the steps are to be limited to a specific order in the claims or specification, it is not intended that any particular order be implied. In addition, as used herein, the article "a" is intended to include one or more than one component or element, and is not intended to be construed as meaning only one.

It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed embodiments without departing from the spirit or scope of the embodiments. Since numerous modifications, combinations, sub-combinations and variations of the disclosed embodiments will readily occur to those skilled in the art, which modifications, combinations, sub-combinations and variations will be apparent to those skilled in the art, the disclosed embodiments are intended to include all the modifications within the scope of the appended claims and their equivalents.

If a numerical range including upper and lower limits is set forth herein, that range is intended to include the endpoints of the range and all integers and fractions within the range, unless the specific context clearly indicates otherwise. The scope of the claims is not limited to the specific values recited when defining the range. Further, when an amount, concentration, or other value or parameter is given as either a range, one or more preferred ranges or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether such pairs are separately disclosed. Finally, when the term "about" is used to describe a value or an endpoint of a range, it is to be understood that the disclosure includes the particular value or endpoint referenced. Whether or not the numerical values or endpoints of ranges are listed using "about," the numerical values or endpoints of ranges are intended to include both embodiments: one modified with "about" and the other not modified with "about".

As used herein, the term "about" means that amounts, sizes, ranges, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller as desired, such as reflection tolerances, conversion factors, rounding off, measurement error, and the like, as well as other factors known to those of skill in the art.

It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.