Acid-corrosion-resistant green LTCC (Low Temperature Co-Fired Ceramic) printing mark slurry and preparation method thereof

Abstract

The invention discloses acid-corrosion-resistant green slurry for LTCC (Low Temperature Co-Fired Ceramic) printing marks and a preparation method of the acid-corrosion-resistant green slurry, belongs to the field of LTCC and manufacturing thereof, and aims to provide slurry for marks, which is good in binding force with a ceramic body and is not easy to fall off after being sintered. The green printing paste capable of being applied to the field of LTCC is prepared from the raw materials according to the proportion of the powder and the organic binder, the paste can be co-fired with an LTCC green tape at the temperature of 850-900 DEG C, a green mark after sintering can be free of color fading and defect after being barreled for 20 minutes through a hydrofluoric acid aqueous solution with the concentration of 0.1 wt% at most, and the preparation method is simple and easy for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of LTCC ceramics (low-temperature co-fired ceramics) and their manufacturing, and proposes an acid-resistant green LTCC printing paste and its preparation method. Background Technology

[0002] LTCC RF devices typically have markings on their surface that differ in color from the ceramic body, such as green, to distinguish the front and back and orientation, ensuring proper electrical testing and functionality at the point of use. However, LTCC devices are usually small in size and have symmetrical electrode pins, making it difficult to mark them with inkjet or laser after the product has been fired.

[0003] Therefore, the most common method for marking LTCC devices is to print green marking paste onto the LTCC green ceramic tape, followed by sintering at 850-900℃. During sintering, the green marking needs to have good adhesion to the ceramic body; otherwise, it will detach after sintering. Additionally, LTCC devices typically require electroplating to ensure solderability, which necessitates the addition of acidic solutions such as hydrochloric acid, sulfuric acid, or hydrofluoric acid during pretreatment. Although the green marking bonds well to the ceramic body after sintering, the marking on the device surface can be corroded and damaged or detached during the pretreatment process, leading to the scrapping of the LTCC device. Summary of the Invention

[0004] To address the above problems, this invention provides an acid-resistant green LTCC printing paste and its preparation method.

[0005] This green printing paste can bond tightly with LTCC ceramic body after sintering at 850-900℃, and can be tumbled in 0.1wt% hydrofluoric acid aqueous solution for 20 minutes without defects or detachment, making it applicable in the LTCC field. The preparation process is simple and the performance is excellent.

[0006] The preparation method is as follows, and all proportions mentioned below are mass ratios: Step 1: Mix the inorganic powders SiO2, Al2O3, CO2O3, ZnO, and B2O3 in a ratio of 50:22:16:(12-x):x (x=3~10) (mass ratio); Step 2: Add the powder and dispersant prepared in Step 1 into a mixing tank containing solvent A. The mixing tank speed is 500 rpm / min. The ratio of inorganic powder, dispersant and solvent A is 100:2.5:180. Use a sand mill to circulate and grind for 1 hour until the D90 particle size is 1.0~2.0um. The sand mill speed is 500~800 rpm (preferably 700 rpm / min). The grinding media is 0.6 mm diameter zirconia beads. Furthermore, in step 2, solvent A is anhydrous ethanol and butanone in a mass ratio of 75:25, and the dispersant is Nippon Oils & Fats Co., Ltd. ESLEAMÒAD-3172M; Step 3: Dissolve the adhesive and solvent B in a water bath at a mass ratio of 1:1.5 to 3, stirring at 100 rpm / min and at a water bath temperature of 60 to 80°C. After complete dissolution, cool to room temperature. Furthermore, the adhesive in step 3 is a mixture of two acrylic resins, with a low molecular weight of 30,000-60,000 and a high molecular weight of 100,000-130,000 in a ratio of 1:4; the solvent B is a mixture of low-boiling-point anhydrous ethanol, butanone, and high-boiling-point diethylene glycol monobutyl ether acetate in a mass ratio of 30:10:60. Step 4: Add the plasticizer to the adhesive mixing tank after step 3 and stir for 3 to 6 hours; the stirring speed is 100 rpm / min and the ratio of adhesive to plasticizer is 10:1.8. Furthermore, the plasticizer mentioned in step 4 is SOFBAR™ P-0803N type from Nippon Oils & Fats Co., Ltd.

[0007] Step 5: Add the inorganic powder slurry after sand milling in Step 2 to the binder and plasticizer mixing tank after Step 4, and stir in a water bath again. Purge nitrogen into the tank for 3 to 10 hours to increase the viscosity to 40,000 to 60,000 Pa·s. The stirring speed is 60 rpm / min, the water bath temperature is 50 to 60°C, and the ratio of inorganic powder to binder is 100:8 to 15. Step 6: Roll the slurry obtained in step 5 on a three-roll mill 2 to 5 times to obtain the required acid-resistant green LTCC printing slurry; wherein the mill spacing is set to 10 μm and the rotation speed is 200 to 500 rpm / min. The beneficial effects of this invention are as follows: the acid-resistant green LTCC printing paste prepared by this invention can bond tightly with the LTCC ceramic body after sintering at 850-900℃, and can be tumbled in 0.1wt% hydrofluoric acid aqueous solution for 20 minutes without defects or detachment, making it applicable in the LTCC field. The preparation process is simple and the performance is excellent. Attached Figure Description

[0008] Figure 1 The images are 40x optical microscope images of the samples from Example 1, from left to right: the sintered sample, the sample milled for 20 minutes with 0.1wt% hydrofluoric acid aqueous solution, and the sample milled for 20 minutes with 0.15wt% hydrofluoric acid aqueous solution.

[0009] Figure 2The images are 40x optical microscope images of the samples from Example 2, from left to right: the sintered sample, the sample milled for 20 minutes with 0.1wt% hydrofluoric acid aqueous solution, and the sample milled for 20 minutes with 0.15wt% hydrofluoric acid aqueous solution. Detailed Implementation

[0010] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0011] Example 1 A method for preparing an acid-resistant, green LTCC printing paste includes: Step 1: Mix the inorganic powders of SiO2, Al2O3, CO2O3, ZnO, and B2O3 in a ratio of 50:22:16:9:3 (by mass). Step 2: Add the powder and dispersant prepared in Step 1 into a mixing tank containing solvent A. The mixing tank speed is 500 rpm / min. The ratio of inorganic powder, dispersant and solvent A is 100:2.5:180. Use a sand mill to circulate and grind for 1 hour until the D90 particle size is 1.8 μm. The sand mill speed is 700 rpm / min. The grinding media is 0.6 mm diameter zirconia beads. Step 3: Dissolve the adhesive and solvent B in a water bath at a mass ratio of 1:2.5 in a water bath stirring tank. The stirring speed is 100 rpm / min and the water bath temperature is 70℃. After complete dissolution, cool to room temperature. Step 4: Add the plasticizer to the adhesive mixing tank after step 3 and stir for 3 hours; the stirring speed is 100 rpm / min and the ratio of adhesive to plasticizer is 10:1.8. Step 5: Add the inorganic powder slurry after sand milling in Step 2 to the binder and plasticizer mixing tank after Step 4, and stir in a water bath again. Purge nitrogen into the tank for 6 hours to increase the viscosity to 50000 Pa·s. The stirring speed is 60 rpm / min, the water bath temperature is 50-60℃, and the ratio of inorganic powder to binder is 100:10. Step 6: The paste obtained in Step 5 is milled three times on a three-roll mill to obtain the required acid-resistant green LTCC printing paste; the mill spacing is set to 10um and the rotation speed is 300rpm / minute. The printing paste prepared above was screen-printed onto a 100*100mm LTCC green ceramic belt, producing 1500 square green logos, each with an area of ​​1.0*1.0mm. After lamination, cutting, and sintering at 900℃ for 2 hours, its corrosion resistance was evaluated by tumbling in hydrofluoric acid aqueous solutions of different concentrations for 20 minutes. The green LTCC printing paste obtained in Example 1 was sintered and then tumbled in hydrofluoric acid aqueous solutions of concentrations of 0.01wt%, 0.05wt%, 0.1wt%, 0.15wt%, and 0.2wt% for 20 minutes, respectively. Figure 1 As shown, when the concentration of hydrofluoric acid is ≤0.1wt%, the green label is intact and does not fall off, while when the concentration is 0.15wt%, the green label falls off almost completely.

[0012] Example 2 A method for preparing an acid-resistant, green LTCC printing paste includes: Step 1: Mix the inorganic powders SiO2, Al2O3, CO2O3, ZnO, and B2O3 in a ratio of 50:22:16:7:5 (by mass). Step 2: Add the powder and dispersant prepared in Step 1 into a mixing tank containing solvent A. The mixing tank speed is 500 rpm / min. The ratio of inorganic powder, dispersant and solvent A is 100:2.5:180. Use a sand mill to circulate and grind for 1 hour until the D90 particle size is 1.8 μm. The sand mill speed is 700 rpm / min. The grinding media is 0.6 mm diameter zirconia beads. Step 3: Dissolve the adhesive and solvent B in a water bath at a mass ratio of 1:2.5 in a water bath stirring tank. The stirring speed is 100 rpm / min and the water bath temperature is 70℃. After complete dissolution, cool to room temperature. Step 4: Add the plasticizer to the adhesive mixing tank after step 3 and stir for 3 hours; the stirring speed is 100 rpm / min and the ratio of adhesive to plasticizer is 10:1.8. Step 5: Add the inorganic powder slurry after sand milling in Step 2 to the binder and plasticizer mixing tank after Step 4, and stir in a water bath again. Purge nitrogen into the tank for 6 hours to increase the viscosity to 50000 Pa·s. The stirring speed is 60 rpm / min, the water bath temperature is 50-60℃, and the ratio of inorganic powder to binder is 100:13. Step 6: The paste obtained in Step 5 is milled three times on a three-roll mill to obtain the required acid-resistant green LTCC printing paste; the mill spacing is set to 10um and the rotation speed is 300rpm / minute. The printing paste prepared above was screen-printed onto a 100*100mm LTCC green ceramic belt, producing 1500 square green logos, each with a pattern area of ​​1.0*1.0mm. After lamination, cutting, and sintering at 875℃ for 2 hours, its corrosion resistance was evaluated by tumbling in hydrofluoric acid aqueous solutions of different concentrations for 20 minutes. The green LTCC printing paste obtained in Example 2 was sintered and then tumbled in hydrofluoric acid aqueous solutions of concentrations of 0.01wt%, 0.05wt%, 0.1wt%, 0.15wt%, and 0.2wt% for 20 minutes each. Figure 2 As shown, in Example 2, the green markings remained clear and undamaged after sintering and after being treated with hydrofluoric acid at a concentration of less than or equal to 0.1 wt%. However, when the hydrofluoric acid concentration was 0.15 wt%, the green markings were corroded and almost completely detached.

[0013] Example 3 A method for preparing an acid-resistant, green LTCC printing paste includes: Step 1: Mix the inorganic powders SiO2, Al2O3, CO2O3, ZnO, and B2O3 in a ratio of 50:22:16:4:8 (by mass). Step 2: Add the powder and dispersant prepared in Step 1 into a mixing tank containing solvent A. The mixing tank speed is 500 rpm / min. The ratio of inorganic powder, dispersant and solvent A is 100:2.5:180. Use a sand mill to circulate and grind for 1 hour until the D90 particle size is 1.8 μm. The sand mill speed is 700 rpm / min. The grinding media is 0.6 mm diameter zirconia beads. Step 3: Dissolve the adhesive and solvent B in a water bath at a mass ratio of 1:2.5 in a water bath stirring tank. The stirring speed is 100 rpm / min and the water bath temperature is 70℃. After complete dissolution, cool to room temperature. Step 4: Add the plasticizer to the adhesive mixing tank after step 3 and stir for 3 hours; the stirring speed is 100 rpm / min and the ratio of adhesive to plasticizer is 10:1.8. Step 5: Add the inorganic powder slurry after sand milling in Step 2 to the binder and plasticizer mixing tank after Step 4, and stir in a water bath again. Purge nitrogen into the tank for 6 hours to increase the viscosity to 50,000 Pa·s. The stirring speed is 60 rpm / min, the water bath temperature is 50-60℃, and the ratio of inorganic powder to binder is 100:15. Step 6: The paste obtained in Step 5 is milled three times on a three-roll mill to obtain the required acid-resistant green LTCC printing paste; the mill spacing is set to 10um and the rotation speed is 300rpm / minute. The printing paste prepared above was screen-printed onto a 100*100mm LTCC green ceramic belt, producing 1500 square green labels, each with a pattern area of ​​1.0*1.0mm. After lamination, cutting, and sintering at 850℃ for 2 hours, its corrosion resistance was evaluated by tumbling in hydrofluoric acid aqueous solutions of different concentrations for 20 minutes. The green LTCC printing paste obtained in Example 3, after sintering, was tumbled in hydrofluoric acid aqueous solutions of concentrations of 0.01wt%, 0.05wt%, 0.1wt%, 0.15wt%, and 0.2wt% for 20 minutes. When the concentration was ≤0.5wt%, the green labels showed no defects or detachment; when the concentration was ≥0.1wt%, some of the green labels were corroded, became lighter in color, and detached.

[0014] In summary, this invention prepares a green printing paste applicable to the LTCC (Low-Temperature Ceramic) field by adjusting the internal ratio of inorganic powder and the ratio of powder to organic binder. This paste can be co-fired with LTCC green ceramic belts at 850-900℃, and the green markings after sintering can remain unfaded and undamaged even after being tumbled in a 0.1wt% hydrofluoric acid aqueous solution for 20 minutes. The preparation method is simple and easy for mass production.

Claims

1. A method for preparing an acid-resistant, green LTCC printing paste for marking, characterized in that, The preparation method includes the following steps: Step 1: Mix the inorganic powders SiO2, Al2O3, CO2O3, ZnO, and B2O3 in a mass ratio of 50:22:16:12-x:x, where x = 3 to 10. Step 2: Add the powder and dispersant prepared in Step 1 into a mixing tank containing solvent A, and stir. The ratio of inorganic powder, dispersant and solvent A is 100:2.5:

180. Use a sand mill to circulate and grind until the D90 particle size is 1.0~2.0um. The sand mill speed is 500~800rpm. Step 3: Dissolve the adhesive and solvent B in a water bath at a mass ratio of 1:1.5 to 3 in a water bath at a temperature of 60 to 80°C. After complete dissolution, cool to room temperature. Step 4: Add the plasticizer to the adhesive mixing tank after step 3 and stir. The ratio of adhesive to plasticizer is 10:1.

8. Step 5: Add the inorganic powder slurry after sand milling in Step 2 to the binder and plasticizer mixing tank after Step 4, and stir in a water bath again. Purge nitrogen into the tank to increase the viscosity to 40,000 to 60,000 Pa·s. The water bath temperature is 50 to 60°C, and the ratio of inorganic powder to binder is 100:8 to 15. Step 6: Grind the slurry obtained in step 5 on a three-roll mill 2 to 5 times to obtain the required acid-resistant green LTCC printing slurry.

2. The method for preparing the acid-resistant green LTCC printing mark paste as described in claim 1, characterized in that, Solvent A in step 2 is anhydrous ethanol and butanone in a mass ratio of 75:

25.

3. The method for preparing an acid-resistant green LTCC printing paste as described in claim 1, characterized in that, The dispersant is AD-3172M.

4. The method for preparing the acid-resistant green LTCC printing and marking paste as described in claim 1, characterized in that, The adhesive mentioned in step 3 is a mixture of two acrylic resins: a low molecular weight acrylic resin (30,000-60,000) and a high molecular weight acrylic resin (100,000-130,000) in a ratio of 1:

4.

5. The method for preparing the acid-resistant green LTCC printing mark paste as described in claim 1, characterized in that, Solvent B is a mixture of low-boiling-point anhydrous ethanol, butanone, and high-boiling-point diethylene glycol monobutyl ether acetic acid, in a mass ratio of 30:10:

60.

6. The method for preparing the acid-resistant green LTCC printing mark paste as described in claim 1, characterized in that, The plasticizer mentioned in step 4 is P-0803N.

7. A green LTCC printing paste resistant to acid corrosion, characterized in that, The green LTCC printing mark paste is prepared using the preparation method described in claim 1.

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