Preparation method of thick film silk screen overprinting slurry

Abstract

The invention discloses a preparation method of thick film silk screen overprinting slurry. Comprising the following steps: S1, mixing a solvent and a binder according to a ratio, heating and uniformly stirring to obtain a clear and transparent organic medium; s2, tungsten powder and a dispersing agent are sequentially added into a roller ball milling tank in proportion, slurry is discharged after ball milling is conducted for 10-30 h at 10-30 HZ, and a mixed solution is obtained; s3, adding the prepared organic medium and the mixed solution into a planetary stirrer, stirring, and vacuumizing the mixed solution; and S4, uniformly rolling the vacuumized slurry by using a three-roller grinder, and filtering by using a filter screen to obtain the silk screen overprinting slurry. The silk screen overprinting slurry prepared by the process is good in printing performance, after printing, the thickness of a film layer can reach 40-45 microns, the surface of the film layer is flat and smooth and free of pits, the volatilization speed of the slurry is moderate in the printing process, a screen printing plate is not blocked, the drying speed is moderate in the drying process after printing, batch printing can be achieved, and storage is stable.

Description

Technical Field

[0001] The invention relates to the technical field of screen overprinting slurries, in particular to a preparation method of thick-film screen overprinting slurries. Background Art

[0002] The SMD ceramic package base is a three-dimensional interconnected structure formed by stacking ceramic green sheets with printed conductive patterns and punched conductive through holes in a certain order and then processing them through an atmosphere-protected sintering process.

[0003] In the prior art, ceramic green bodies printed with conductive patterns have the following problems: the surface of the overprinted tungsten slurry layer is rough and uneven, with depressions, uneven printed lines, and slurry deficiency. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the present invention provides a method for preparing a thick-film screen overprinting slurry.

[0005] Under the action of screen printing, the metallized tungsten slurry is printed on the ceramic green body for the first time to form a uniform, fine, continuous and complete metal tungsten slurry layer. After drying, on this basis, a layer of metal tungsten slurry with a different pattern and a thickness of 40-45um is printed on the tungsten slurry layer for the second time to achieve a good interconnection and conduction effect.

[0006] In order to solve the above technical problems, the present invention is solved by the following technical solutions: A method for preparing a thick film screen overprinting slurry comprises the following steps: S1. Mix the solvent and the binder in proportion, heat and stir evenly to obtain a clear and transparent organic medium; S2. Add tungsten powder and dispersant in a drum ball mill in proportion, and mill at 10-30 Hz for 10-30 hours to obtain a slurry to obtain a mixed solution; S3, adding the prepared organic medium and mixed solution into a planetary mixer, stirring and vacuuming the mixed solution; S4. The vacuumed slurry is rolled uniformly with a three-roll mill and filtered through a filter to obtain a screen printing slurry.

[0007] In the above technical solution, preferably, in step S1, the solvent is one or more of tributyl citrate, polyol acetate, butyl carbitol acetate, propylene glycol butyl ether acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate; and the binder is one or more of ethyl cellulose, polyvinyl butyral, and acrylic resin.

[0008] Specifically, the solvent is a mixture of tributyl citrate, polyol acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate; and the binder is a mixture of polyvinyl butyral and ethyl cellulose.

[0009] In the above technical solution, preferably, in step S1, 30 g of tributyl citrate, 30 g of polyol acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate are mixed, and then 5 g of polyvinyl butyral and 5 g of ethyl cellulose are added, and the mixture is stirred at 80° C. for 60 min to obtain a transparent and clear organic medium; In step S2, 1000 grams of tungsten powder and 500 grams of dispersant are added.

[0010] In the above technical solution, preferably, in step S1, the ratio of the solvent to the binder is 9:1; and in step S2, the ratio of the tungsten powder to the dispersant is 2:1.

[0011] In the above technical solution, preferably, in step S2, the slurry is obtained after ball milling at 20 Hz for 24 hours.

[0012] In the above technical solution, preferably, in step S3, the vacuum degree range of the vacuum pumping is -0.04--0.095Mpa.

[0013] In the above technical solution, preferably, the filter screen in step S4 has 500 meshes.

[0014] The beneficial effects of the present invention are: The screen printing slurry prepared by the process of the present invention has good printing performance. After printing, the film thickness can reach 40-45 μm, the film surface is flat and smooth without depression, the slurry volatilization speed is moderate during the printing process, and the screen is not blocked. The drying speed during the drying process after printing is moderate, and batch printing can be performed and storage is stable. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with specific embodiments: A method for preparing a thick film screen overprinting slurry comprises the following steps: S1, mixing a solvent and a binder in proportion, heating and stirring to obtain a clear and transparent organic medium, wherein the ratio of the solvent to the binder is 9:1; S2. Add tungsten powder and dispersant in a drum ball mill in a ratio of 2:1. For example, add 1000 g of tungsten powder and 500 g of dispersant, and mill at 10-30 Hz for 10-30 hours to obtain a slurry to obtain a mixed solution. Specifically, mill at 20 Hz for 24 hours to obtain a slurry. S3. Add the prepared organic medium and mixed solution into a planetary mixer, stir and evacuate the mixed solution, the vacuum degree range of the evacuation is -0.04--0.095Mpa.

[0016] S4. The vacuumed slurry is rolled uniformly with a three-roll mill, and filtered through a filter to obtain a screen printing slurry, wherein the filter has 500 meshes.

[0017] In step S1, the solvent is one or more of tributyl citrate, polyol acetate, butyl carbitol acetate, propylene glycol butyl ether acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate; the binder is one or more of ethyl cellulose, polyvinyl butyral, and acrylic resin.

[0018] Example: 30 g of tributyl citrate, 30 g of polyol acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were mixed, 5 g of polyvinyl butyral and 5 g of ethyl cellulose were added, and the mixture was stirred at 80° C. for 60 min to obtain a transparent and clear organic medium.

[0019] 1000 g of tungsten powder and 500 g of dispersant were added to a drum ball mill in proportion, and the mixture was milled at a frequency of 20 Hz for 24 hours to obtain a slurry to obtain a mixed solution.

[0020] The prepared organic medium and mixed solution were added to a planetary mixer, stirred, and the mixed solution was evacuated at a vacuum degree of -0.04 to -0.095 MPa.

[0021] The vacuumed slurry was rolled uniformly with a three-roll mill and filtered through a 500-mesh filter to obtain a screen printing slurry.

[0022] The above-mentioned screen printing slurry is printed on the product, and the film layer thickness is 40-45um. The film layer surface is flat and smooth without depressions, and the slurry layer is continuous and complete.

[0023] Comparative Example 1: 30 g of tributyl citrate, 30 g of polyol acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were mixed, 5 g of polyvinyl butyral and 5 g of ethyl cellulose were added, and the mixture was stirred at 80° C. for 60 min to obtain a transparent and clear organic medium.

[0024] 1000 g of tungsten powder and 500 g of dispersant were added to the drum ball mill in proportion. The slurry was obtained after ball milling at a frequency of 20 Hz for 24 hours. The dried powder was sieved for later use.

[0025] The powder and the organic medium are mixed evenly, the materials are rolled evenly with a three-roll mill, and filtered with a 500-mesh filter to obtain a screen printing slurry.

[0026] The above-mentioned screen printing slurry is printed on the product, and the film thickness is 40-45um. There are screen prints and particle agglomeration on the surface of the film.

[0027] Comparative Example 2: 30 g of tributyl citrate, 30 g of butyl carbitol acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were mixed, 5 g of polyvinyl butyral and 5 g of ethyl cellulose were added, and the mixture was stirred at 80° C. for 60 min to obtain a transparent and clear organic medium.

[0028] 1000 g of tungsten powder and 500 g of dispersant were added to a drum ball mill in proportion, and the mixture was milled at a frequency of 20 Hz for 24 hours to obtain a slurry to obtain a mixed solution.

[0029] The prepared organic medium and mixed solution were added to a planetary mixer, stirred, and the mixed solution was evacuated at a vacuum degree of -0.04 to -0.095 MPa.

[0030] The vacuumed slurry was rolled uniformly with a three-roll mill and filtered through a 500-mesh filter to obtain a screen printing slurry.

[0031] The above-mentioned screen printing slurry is printed on the product, and the film layer thickness is 40-45um. The film layer surface is flat and smooth, with a slight depression of 5um in depth. The film layer dries slowly, which affects the printing of the next process.

[0032] Comparative Example 3: 30 g of tributyl citrate, 30 g of propylene glycol butyl ether acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were mixed, 5 g of polyvinyl butyral and 5 g of ethyl cellulose were added, and the mixture was stirred at 80° C. for 60 min to obtain a transparent and clear organic medium.

[0033] 1000 g of tungsten powder and 500 g of dispersant were added to a drum ball mill in proportion, and the mixture was milled at a frequency of 20 Hz for 24 hours to obtain a slurry to obtain a mixed solution.

[0034] The prepared organic medium and mixed solution were added to a planetary mixer, stirred, and the mixed solution was evacuated at a vacuum degree of -0.04 to -0.095 MPa.

[0035] The vacuumed slurry was rolled uniformly with a three-roll mill and filtered through a 500-mesh filter to obtain a screen printing slurry.

[0036] The above-mentioned screen printing slurry is printed on the product, and the film thickness is 40-45um. The film surface is flat and smooth, and the middle of the film is concave with a depth of 8um. In addition, the slurry evaporates quickly, the screen is blocked, and batch printing cannot be carried out.

[0037] Comparative Example 4: 30 g of tributyl citrate, 30 g of polyol acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were mixed, 10 g of ethyl cellulose was added, and the mixture was stirred at 80° C. for 60 min to obtain a transparent and clear organic medium.

[0038] 1000 g of tungsten powder and 500 g of dispersant were added to a drum ball mill in proportion, and the mixture was milled at a frequency of 20 Hz for 24 hours to obtain a slurry to obtain a mixed solution.

[0039] The prepared organic medium and mixed solution were added to a planetary mixer, stirred, and the mixed solution was evacuated at a vacuum degree of -0.04 to -0.095 MPa.

[0040] The vacuumed slurry was rolled uniformly with a three-roll mill and filtered through a 500-mesh filter to obtain a screen printing slurry.

[0041] The above-mentioned screen printing slurry is printed on the product, and the film layer thickness is 30-35um. The film layer surface is flat and smooth without depressions, and the slurry layer is continuous and complete.

[0042] Comparative Example 5: 30 g of tributyl citrate, 30 g of polyol acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were mixed, 10 g of polyvinyl butyral was added, and the mixture was stirred at 80° C. for 60 min to obtain a transparent and clear organic medium.

[0043] 1000 g of tungsten powder and 500 g of dispersant were added to a drum ball mill in proportion, and the mixture was milled at a frequency of 20 Hz for 24 hours to obtain a slurry to obtain a mixed solution.

[0044] The prepared organic medium and mixed solution were added to a planetary mixer, stirred, and the mixed solution was evacuated at a vacuum degree of -0.04 to -0.095 MPa.

[0045] The vacuumed slurry was rolled uniformly with a three-roll mill and filtered through a 500-mesh filter to obtain a screen printing slurry.

[0046] The above-mentioned screen printing slurry is printed on the product, with a film layer thickness of 40-45 μm, a depression in the middle of the film layer, and a depression depth of 12 μm.

[0047] Comparative Example 6: 30 g of tributyl citrate, 30 g of polyol acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were mixed, 10 g of acrylic resin was added, and the mixture was stirred at 80° C. for 60 min to obtain a transparent and clear organic medium.

[0048] 1000 g of tungsten powder and 500 g of dispersant were added to a drum ball mill in proportion, and the mixture was milled at a frequency of 20 Hz for 24 hours to obtain a slurry to obtain a mixed solution.

[0049] The prepared organic medium and mixed solution were added to a planetary mixer, stirred, and the mixed solution was evacuated at a vacuum degree of -0.04 to -0.095 MPa.

[0050] The vacuumed slurry was rolled uniformly with a three-roll mill and filtered through a 500-mesh filter to obtain a screen printing slurry.

[0051] The above-mentioned screen printing slurry is printed on the product, and the film layer thickness is 40-45um. The surface of the film layer is flat and smooth without depressions, but the surface metal layer has a wire drawing phenomenon, which is easy to contaminate the product.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a thick film screen printing paste, characterized in that: The following steps are involved: S1. Mix the solvent and the binder in proportion, heat and stir evenly to obtain a clear and transparent organic medium; S2. Add tungsten powder and dispersant in a drum ball mill in proportion, and mill at 10-30 Hz for 10-30 hours to obtain a slurry to obtain a mixed solution; S3, adding the prepared organic medium and mixed solution into a planetary mixer, stirring and vacuuming the mixed solution; S4. The vacuumed slurry is rolled uniformly with a three-roll mill and filtered through a filter to obtain a screen printing slurry.

2. The method for preparing a thick film screen printing paste according to claim 1, characterized in that: In step S1, the solvent is a mixture of tributyl citrate, polyol acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate.

3. The method for preparing a thick film screen printing paste according to claim 1 or 2, characterized in that: In step S1 , the binder is a mixture of polyvinyl butyral and ethyl cellulose.

4. The method for preparing a thick film screen printing paste according to claim 3, wherein: In step S1, 30 g of tributyl citrate, 30 g of polyol acetate, and 30 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were mixed, and then 5 g of polyvinyl butyral and 5 g of ethyl cellulose were added, and the mixture was stirred at 80° C. for 60 min to obtain a transparent and clear organic medium; In step S2, 1000 grams of tungsten powder and 500 grams of dispersant are added.

5. The method for preparing a thick film screen printing paste according to claim 1, wherein: In step S1, the solvent is one or more of tributyl citrate, polyol acetate, butyl carbitol acetate, propylene glycol butyl ether acetate, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate.

6. A method for preparing a thick film screen printing paste according to claim 1 or 4, characterized in that: In step S1, the binder is one or more of ethyl cellulose, polyvinyl butyral, and acrylic resin.

7. The method for preparing a thick film screen printing paste according to claim 1, wherein: In step S1, the ratio of solvent to binder is 9:1; In step S2, the ratio of tungsten powder to dispersant is 2:

1.

8. The method for preparing a thick film screen printing paste according to claim 1, wherein: In step S2, the slurry is obtained after ball milling at 20 Hz for 24 hours.

9. The method for preparing a thick film screen printing paste according to claim 1, wherein: In step S3, the vacuum degree range of the vacuum pumping is -0.04--0.095Mpa.

10. The method for preparing a thick film screen printing paste according to claim 1, wherein: In step S4, the filter screen is 500 mesh.