Brazing glue and preparation method thereof

Abstract

The invention discloses glue for brazing and a preparation method thereof. Comprising the following steps: S1, putting an organic solvent and a surfactant into a container in proportion, and stirring for 30-60 minutes at the temperature of 60-80 DEG C; s2, adding a high-molecular polymer, and stirring until the mixture is transparent; and S3, cooling after passing through a filtering device to obtain the glue. Compared with the conventional commercially available glue, the glue can be removed completely under the non-oxygen condition and the sintering condition of more than 600 DEG C; the viscosity can be adjusted according to actual requirements, and the requirement for mechanical efficiency in the dispensing process is met.

Description

Technical Field

[0001] The invention relates to the technical field of soldering glue, in particular to soldering glue and a preparation method thereof. Background Art

[0002] After electroplating, the ceramic package base requires brazing to bond the metal ring to the ceramic base. The brazing process involves applying glue to the ceramic base and then aligning the metal ring to secure it. The glue is removed in a brazing furnace at temperatures exceeding 800°C, while the solder on the metal ring melts and bonds to the ceramic. After cooling, the metal ring and ceramic base are bonded.

[0003] Brazing furnaces operate in a non-oxygen atmosphere, typically a mixture of hydrogen and nitrogen. In this atmosphere, conventional glue is difficult to remove completely, resulting in carbon residues that can cause defects such as solder blistering and solder floating, affecting the bonding between the metal ring and the ceramic base. Summary of the Invention

[0004] The present invention addresses the deficiencies in the prior art and provides a soldering glue and a preparation method thereof. By using a high molecular weight polymer that is easily decomposed in a non-oxidizing atmosphere, a solvent that is highly compatible with the polymer, and a surfactant that reduces the surface tension of the glue, a soldering glue with a viscosity greater than 20 Pa·s is produced, which meets the requirements of a dispensing machine and can be cleanly removed under sintering conditions exceeding 600°C in a non-oxidizing atmosphere.

[0005] In order to solve the above technical problems, the present invention is solved by the following technical solutions: A soldering glue is prepared from the following raw materials in parts by weight: 10-30 parts by weight of a high molecular polymer, 60-85 parts by weight of an organic solvent and 5-10 parts by weight of a surfactant.

[0006] The high molecular polymer is one or more of polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, hydrogenated rosin ester, polypropylene carbonate, and poly-α-methylstyrene.

[0007] The organic solvent is one or more of toluene, turpentine, tributyl citrate, dimethylformamide, mineral oil, methyl pyrrolidone pentanedione, butyl acetate, glycerol, propylene carbonate, and dipropylene glycol methyl ether acetate.

[0008] The surfactant is one or more of lecithin, titanate coupling agent, polyamide wax, polyacrylic acid, octadecylamine, glyceryl stearate, 1,4-butyrolactone, sodium lauryl sulfate, methyl amyl alcohol, oleyl amino oleate, and oleic acid.

[0009] A method for preparing soldering glue comprises the following steps: S1. Place the organic solvent and surfactant in a container in proportion and stir at 60-80°C for 30-60 minutes; S2. Add high molecular weight polymer and stir until the mixture becomes transparent; S3, after passing through a filtering device and cooling, glue is obtained.

[0010] In the above technical solution, preferably, the weight ratio of the high molecular weight polymer, the organic solvent and the surfactant is 20:70:10.

[0011] In the above technical solution, preferably, in step S1, the stirring speed is 200-1000 rpm.

[0012] In the above technical solution, preferably, in step S2, the stirring speed is 200-500 rpm.

[0013] In the above technical solution, preferably, in step S3, the filtering device is a stainless steel mesh.

[0014] In the above technical solution, preferably, in step S3, the mesh size of the filtering device is greater than or equal to 2000 meshes.

[0015] The beneficial effects of the present invention are: Compared with conventional commercially available glue, the glue of the present invention can be removed cleanly under non-oxygen conditions and sintering conditions above 600°C; the viscosity and stickiness can be adjusted according to actual needs to meet the requirements of mechanical efficiency in the dispensing process. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with specific embodiments: A soldering glue comprises a high molecular weight polymer, an organic solvent, and a surfactant. Specifically, the glue is prepared from the following raw materials in parts by weight: 10-30 parts by weight of a high molecular polymer, 60-85 parts by weight of an organic solvent and 5-10 parts by weight of a surfactant.

[0017] The high molecular polymer includes but is not limited to polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, hydrogenated rosin ester, polypropylene carbonate, and poly-α-methylstyrene. When used, one or more of them can be selected.

[0018] The organic solvent includes but is not limited to toluene, turpentine, tributyl citrate, dimethylformamide, mineral oil, methyl pyrrolidone pentaerythritol, butyl acetate, glycerol, propylene carbonate, and dipropylene glycol methyl ether acetate. When used, one or more of them can be selected.

[0019] Surfactants include but are not limited to lecithin, titanate coupling agent, polyamide wax, polyacrylic acid, octadecylamine, glyceryl stearate, 1,4-butyrolactone, sodium lauryl sulfate, methyl amyl alcohol, oleyl amino oleate, and oleic acid. When used, one or more of them can be selected.

[0020] Polymers are composed of a combination of different organic molecular functional groups. Their properties are determined by their chain structure and the types of functional groups. Polymers with more polar functional groups exhibit stronger interactions between their chains, are more likely to interact with themselves and other substances, and exhibit better adhesion. The chain length and structure of polymers affect the viscosity of polymer solutions. The higher the molecular weight of a polymer, the longer its chains, and the fewer branches it has, the higher its viscosity.

[0021] In a non-oxidizing atmosphere, high polymer chains break into fragments at high temperatures. If the polymer has high bond energy, it is not easily broken down, resulting in longer fragments that are deposited as solids on the product surface, representing carbon residues. The more branched chains there are, the lower the bond energy of the functional groups, making them more susceptible to breaking down at high temperatures to form smaller molecules. These small molecules are then expelled from the furnace atmosphere as a gas at high temperatures, preventing the formation of carbon residues.

[0022] A method for preparing soldering glue comprises the following steps: S1. Place the organic solvent and surfactant in a container in proportion, stir at 60-80°C for 30-60 minutes at a stirring speed of 200-1000 rpm; S2. Add high molecular weight polymer and stir until the mixture becomes transparent at a stirring speed of 200-500 rpm; S3, cooling after passing through a filtering device to obtain glue, wherein the filtering device can be made of stainless steel mesh with a mesh size greater than or equal to 2000 meshes.

[0023] The weight ratio of the high molecular weight polymer, the organic solvent and the surfactant is 10:85:5 or 30:60:10 or 20:70:10 or 20:75:5.

[0024] The polymer provides the adhesive's viscosity, ensuring adhesion between the metal ring and the ceramic. The organic solvent dissolves the polymer, making the adhesive fluid and suitable for the dispensing process. The surfactant reduces the adhesive's surface tension, making it easier to wet the metal ring and ceramic, and providing improved interfacial ductility.

[0025] The glue can meet the requirements of automatic ring pasting by machines and brazing under non-oxidizing conditions. It decomposes completely without adversely affecting the porcelain body, solder, or alloy rings. It meets the high efficiency and high quality requirements of high-speed ring pasting and non-oxidizing atmosphere welding of alloy rings.

[0026] Example 1: Polyvinyl butyral, tributyl citrate, toluene and lecithin were prepared in a weight ratio of 10:20:65:5.

[0027] First, 20 parts of tributyl citrate, 65 parts of toluene and 5 parts of lecithin are placed in a container in proportion, stirred at 80°C for 30 minutes at a stirring speed of 200 rpm, and then 10 parts of polyvinyl butyral are added. After stirring until the mixture becomes transparent, it is cooled, filtered through a 2000 mesh stainless steel mesh, and cooled to room temperature to obtain a bonding glue.

[0028] Example 2: Hydrogenated rosin ester, turpentine, and polyamide wax were prepared in a weight ratio of 30:60:10. 60 parts turpentine and 10 parts polyamide wax were placed in a container and stirred at 80°C for 60 minutes at a stirring speed of 1000 rpm. Then, 30 parts hydrogenated rosin ester was added and stirred until the mixture became transparent. The mixture was then cooled, filtered through a 2000-mesh stainless steel mesh, and cooled to room temperature to obtain a bonding adhesive.

[0029] Example 3: Polypropylene carbonate, propylene carbonate, dipropylene glycol methyl ether acetate, butyl acetate, and octadecylamine were prepared in a weight percentage ratio of 20:40:20:10:10. First, 40 parts of propylene carbonate, 20 parts of dipropylene glycol methyl ether acetate, 10 parts of butyl acetate, and 10 parts of octadecylamine were placed in a container in the appropriate proportions and stirred at 60°C for 30 minutes at a stirring speed of 200 rpm. Then, 20 parts of polypropylene carbonate was added and stirred until the mixture became transparent. The mixture was then cooled, filtered through a 2000-mesh stainless steel mesh, and cooled to room temperature to obtain a bonding adhesive.

[0030] Example 4: Polypropylene carbonate, propylene carbonate, dipropylene glycol methyl ether acetate, butyl acetate, and polyamide wax were prepared in a weight percentage ratio of 20:40:20:10:10. First, 40 parts of propylene carbonate, 20 parts of dipropylene glycol methyl ether acetate, 10 parts of butyl acetate, and 10 parts of polyamide wax were placed in a container in the appropriate proportions and stirred at 80°C for 60 minutes at a stirring speed of 1000 rpm. Then, 20 parts of polypropylene carbonate was added and stirred until the mixture became transparent. The mixture was then cooled, filtered through a 2000-mesh stainless steel mesh, and cooled to room temperature to obtain a bonding adhesive.

[0031] Example 5: Poly(α-methylstyrene), propylene carbonate, toluene, mineral oil, and oleic acid were prepared in a weight ratio of 20:50:20:5:5. First, 50 parts propylene carbonate, 20 parts toluene, 5 parts mineral oil, and 5 parts oleic acid were placed in a container and stirred at 60°C for 30 minutes at 200 rpm. Then, 20 parts poly(α-methylstyrene) was added. Stir until the mixture became transparent, then cool, filter through a 2000-mesh stainless steel mesh, and cool to room temperature to obtain a bonding adhesive.

[0032] The viscosity and carbon residue of the glue were tested by a rotational viscometer and an EDS spectrometer.

[0033] The bonding is qualified by bonding the metal ring and vibrating it on a vibration machine based on the displacement of the metal ring. If the displacement of the metal ring is greater than 3um, it is unqualified.

[0034] Test results table: Viscosity (Pa·S) Carbon residue Adhesion Example 1 19.6 12% qualified Example 2 21.4 15% qualified Example 3 22.2 0.09% qualified Example 4 25.3 0.12% qualified Example 5 20.3 1.4% Unqualified It can be seen from the above test result table that the preparation methods of Example 3 and Example 4 are the best.

[0035] 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 soldering glue, characterized in that: The glue is prepared from the following raw materials in parts by weight: 10-30 parts by weight of a high molecular weight polymer, 60-85 parts by weight of an organic solvent and 5-10 parts by weight of a surfactant.

2. The soldering glue according to claim 1, wherein: The high molecular polymer is one or more of polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, hydrogenated rosin ester, polypropylene carbonate, and poly-α-methylstyrene.

3. The soldering glue according to claim 1, wherein: The organic solvent is one or more of toluene, turpentine, tributyl citrate, dimethylformamide, mineral oil, methyl pyrrolidone pentaerythritol, butyl acetate, glycerol, propylene carbonate, and dipropylene glycol methyl ether acetate.

4. The soldering glue according to claim 1, wherein: The surfactant is one or more of lecithin, titanate coupling agent, polyamide wax, polyacrylic acid, octadecylamine, glyceryl stearate, 1,4-butyrolactone, sodium lauryl sulfate, methyl amyl alcohol, oleyl amino oleate, and oleic acid.

5. A method for preparing soldering glue, characterized in that: The following steps are involved: S1. Place the organic solvent and surfactant in a container in proportion and stir at 60-80°C for 30-60 minutes; S2. Add high molecular weight polymer and stir until the mixture becomes transparent; S3, after passing through a filtering device and cooling, glue is obtained.

6. The method for preparing soldering glue according to claim 5, wherein: The weight ratio of the high molecular weight polymer, the organic solvent and the surfactant is 20:70:

10.

7. The method for preparing soldering glue according to claim 5, wherein: In step S1, the stirring speed is 200-1000 rpm.

8. The method for preparing soldering glue according to claim 5, wherein: In step S2, the stirring speed is 200-500 rpm.

9. The method for preparing soldering glue according to claim 5, wherein: In step S3, the filtering device is a stainless steel mesh.

10. The method for preparing a soldering glue according to claim 5 or 9, characterized in that: In step S3, the mesh size of the filter device is greater than or equal to 2000 meshes.