Low-spatter and low-smoke solder wire flux and preparation method thereof

Abstract

The present invention relates to a low-splash and low-smoke solder wire flux and a preparation method thereof, which comprises, by weight, 80-86.5% of a rosin mixture, 0.9-1.4% of a film former, 5-9.5% of a film-forming aid, 5-8% of a surfactant, 0.3-0.5% of a compound solvent and 1.5-5.5% of an antioxidant; the rosin mixture comprises gum rosin and hydrogenated rosin, and the compound solvent comprises phenyl glycol and propylene glycol butyl ether. The soldering flux prepared by the present invention has good high temperature resistance and high acid value, and reduces the smoke generated during welding; a specific film former is adopted, and has excellent bonding performance and weather resistance, and can react rapidly at room temperature to form a strong mesh structure, so that the soldering flux system has good hydrophobicity, improves the moisture resistance of the solder wire, and thus reduces the phenomenon of solder wire splashing during welding.

Description

Technical Field

[0001] The invention relates to the field of soldering flux, in particular to a soldering flux with low spatter and little smoke. Background Art

[0002] The flux is mainly composed of rosin. As an indispensable auxiliary material in the welding process, its main function is to remove oxides on the surface of solder and welding base material and keep the metal surface clean. In addition, the flux can prevent re-oxidation during the welding process, reduce the surface tension of the solder, and help heat conduction, thereby expanding the welding area and improving welding performance. The performance of the flux is directly related to the quality of electronic products.

[0003] In the field of electronic packaging, solder wire is a common material for manual or semi-automatic welding. It is used in conjunction with electric soldering irons or lasers. The melted tin alloy is used as a filler material to fix electronic components. With the rapid development of electronic products, the performance requirements of solder wire are constantly increasing. The spatter and smoke in the soldering process have become key indicators to measure its quality. These problems not only affect product quality, but may also pose risks to the health of operators.

[0004] Solder wire is usually composed of tin alloy and flux. The flux is a chemical substance that can promote or accelerate the wetting of metal by molten solder during the welding process, and at the same time has a protective effect and prevents oxidation reaction. The rosin in the existing flux is easy to carbonize when it exceeds 300℃, while the common temperature of the electric soldering iron is between 360 and 450℃. The carbonization of rosin at high temperature will produce a lot of smoke, which is not only harmful to the health of operators, but also may affect the quality of the environment. On the other hand, high temperature will cause the flux to decompose faster, generate more gas, and increase the possibility of spatter. Summary of the invention

[0005] In view of the above analysis, the problem to be solved by the present invention is to reduce the smoke and splashing of rosin when using an electric soldering iron.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions:

[0007] A low-spatter and low-smoke solder wire flux, comprising, by weight, 80-86.5% of a rosin mixture, 0.9-1.4% of a film former, 5-9.5% of a film-forming aid, 5-8% of a surfactant, 0.3-0.5% of a compound solvent, and 1.5-5.5% of an antioxidant;

[0008] The rosin mixture comprises gum rosin and hydrogenated rosin, and the compound solvent comprises phenyl glycol and propylene glycol butyl ether.

[0009] In one or more embodiments, the film former is one or more of polyvinyl pyrrolidone / hexadecene copolymer, trimethylsiloxysilicate, acrylic resin and dimethylsiloxane copolymer.

[0010] In one or more embodiments, the film-forming aid is one or more of ethylene glycol, propylene glycol, dodecyl alcohol ester and turpentine.

[0011] In one or more embodiments, the surfactant is one or more of FSN-100, FC-4430, FS-3100 and FSO-100.

[0012] In one or more embodiments, the antioxidant is at least one of Ciba antioxidant 1010 and antioxidant BHT.

[0013] A method for preparing a low-splash and low-smoke solder wire flux comprises the following steps:

[0014] Mix gum rosin and hydrogenated rosin in proportion, add compound solvent, and then heat to soften the rosin. Start stirring with a stirrer. When the composite rosin reaches a molten state, add a film-forming agent, a film-forming aid, a surfactant and an antioxidant. Continue heating and stirring. After the mixture is completely dissolved, continue heating and stirring for 20 minutes, stop the reaction, and cool to room temperature to obtain a solder wire flux.

[0015] In one or more embodiments, the heating and stirring temperature is 200-220° C. For example, it can be 200° C., 210° C., 220° C., etc.

[0016] In one or more embodiments, the heating stirring speed is 500-1000 rpm, for example, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, etc.

[0017] In one or more embodiments, the heating and stirring time is 1-2 hours, for example, 1 hour, 1.5 hours, 2 hours, etc.

[0018] Principle of the present invention: The present invention significantly enhances the stability of the flux system and improves the high temperature resistance by adding high temperature resistant rosin and utilizing hydrogen bond cross-linking between the rosin and the film-forming agent to form a mesh structure. The selected surfactant has excellent internal wetting ability, thereby enhancing the wetting effect of the solder wire. In addition, as a coupling agent for fillers, it not only improves the insulation performance of the material and prevents the migration of electrons, but also acts as an adhesive to increase the fluidity of the solder and the spreadability of the solder joint, thereby improving the reliability of the solder joint. After precise viscosity adjustment, this flux can also effectively reduce spattering during welding and reduce the health risks to welders. The solder wire prepared using the present invention generates less smoke during use, reducing the health impact on welders.

[0019] The technical solution of the present invention can achieve at least one of the following effects:

[0020] 1. The flux prepared by the present invention has good high temperature resistance and high acid value, which reduces the smoke generated during welding; a specific film-forming agent is used, which has excellent bonding performance and weather resistance, and can react quickly at room temperature to form a strong network structure, so that the flux system has good hydrophobicity, improves the moisture-proof performance of the solder wire, and thus reduces the phenomenon of solder wire splashing during welding.

[0021] 2. The flux expansion rate prepared by the present invention is ≥80%, and the insulation resistance is greater than 1×10 8 Ω, less splashing.

[0022] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0024] Figure 1 This is a test diagram of the surface insulation resistance of the soldering flux in Example 1 of the present invention.

[0025] Figure 2 This is a test diagram of the surface insulation resistance of the soldering flux in Example 2 of the present invention.

[0026] Figure 3 This is a test diagram of the surface insulation resistance of the soldering flux in Example 3 of the present invention.

[0027] Figure 4 This is a test diagram of the surface insulation resistance of the soldering flux of Comparative Example 1 of the present invention.

[0028] Figure 5 This is a test diagram of the surface insulation resistance of the soldering flux of Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0030] The technical scheme of the present invention is further described below in conjunction with specific embodiments, but the present invention should not be limited to these embodiments, unless otherwise described, they can be replaced by other equivalent or alternative features with similar purposes. Unless otherwise described, each feature is just an example in a series of equivalent or similar features. The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by ordinary technicians in the field. In the following examples, unless otherwise specified, concentration % refers to mass percentage; the substances used can be obtained commercially. The technical scheme of the present invention is further described below in conjunction with specific embodiments, but the present invention should not be limited to these embodiments, unless otherwise described, they can be replaced by other equivalent or alternative features with similar purposes. Unless otherwise described, each feature is just an example in a series of equivalent or similar features. The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by ordinary technicians in the field.

[0031] Example 1

[0032] This embodiment provides a low-spatter and low-smoke solder wire flux, which includes, by weight:

[0033] 52% gum rosin, 33% hydrogenated rosin and 0.2% phenyl glycol, 0.2% propylene glycol butyl ether, 1.2% polyvinyl pyrrolidone / hexadecene copolymer, 5.4% dodecyl alcohol ester, 2% FSN-100 and 3% FSO-100, 3% Ciba antioxidant 1010.

[0034] The preparation method of low spatter and low smoke solder wire flux comprises the following steps:

[0035] Add 52% gum rosin, 33% hydrogenated rosin, 0.2% phenyl glycol, and 0.2% propylene glycol butyl ether into a container, heat to 220°C, and stir until completely melted. When the composite rosin reaches a molten state, add 1.2% oily film-forming agent polyvinyl pyrrolidone / hexadecene copolymer, 5.4% film-forming aid dodecyl alcohol ester, 2% surfactant FSN-100 and 3% FSO-100, and 3% Ciba antioxidant 1010 in sequence, continue heating and stirring for 30 minutes, and continue heating and stirring for 20 minutes after the mixture is completely dissolved, stop the reaction, and cool to room temperature to obtain a solder wire flux with low spatter and less smoke.

[0036] Example 2

[0037] This embodiment provides a low-spatter and low-smoke solder wire flux, which includes, by weight:

[0038] 53% gum rosin, 31% hydrogenated rosin and 0.3% phenyl glycol, 0.2% propylene glycol butyl ether, 1.3% trimethylsiloxysilicate, 5% turpentine, 2.5% FSN-100 and 3.4FSO-100, 3.3% Ciba antioxidant 1010

[0039] The preparation method of low spatter and low smoke solder wire flux comprises the following steps:

[0040] Add 53% gum rosin, 31% hydrogenated rosin, 0.3% phenyl glycol, and 0.2% propylene glycol butyl ether into a container, heat to 220°C, and stir until completely melted. When the composite rosin reaches a molten state, add 1.3% film-forming agent trimethylsiloxysilicate, 5% film-forming aid turpentine, 5.9% surfactants FSN-100 and FS-100, and 3.3% Ciba antioxidant 1010 in sequence, continue heating and stirring for 30 minutes, and continue heating and stirring for 20 minutes after the mixture is completely dissolved, stop the reaction, and cool to room temperature to obtain a solder wire flux with low spatter and less smoke.

[0041] Example 3

[0042] This embodiment provides a low-spatter and low-smoke solder wire flux, which includes, by weight:

[0043] 50% gum rosin, 30% hydrogenated rosin, 0.2% phenyl glycol, 0.2% propylene glycol butyl ether, 1.4% film-forming agent acrylic resin and dimethylsiloxane copolymer, 8% ethylene glycol and propylene glycol, 5.2% FS-3100, 2.8% FSO-100, 2.2% antioxidant BHT.

[0044] The preparation method of low spatter and low smoke solder wire flux comprises the following steps:

[0045] Add 50% gum rosin, 30% hydrogenated rosin, 0.2% phenyl glycol, and 0.2% propylene glycol butyl ether into a container, heat to 220°C, and stir until completely melted. When the composite rosin reaches a molten state, add 1.4% of a film-forming agent propylene resin and dimethylsiloxane copolymer, 8% of film-forming aids ethylene glycol and propylene glycol, 8% of surfactants FS-3100 and FS0-100, and 2.2% of antioxidant BHT in sequence, and continue to heat and stir for 30 minutes. After the mixture is completely dissolved, continue to heat and stir for 20 minutes, stop the reaction, and cool to room temperature to obtain a solder wire flux with low spatter and less smoke.

[0046] Comparative Example 1

[0047] This embodiment provides a low-spatter and low-smoke solder wire flux, which includes, by weight:

[0048] 52% maleic rosin, 33% hydrogenated rosin and 0.2% phenyl glycol, 0.2% propylene glycol butyl ether, 1.2% polyvinyl pyrrolidone / hexadecene copolymer, 5.4% dodecyl alcohol ester, 2% FSN-100 and 3% FSO-100, 3% Ciba antioxidant 1010.

[0049] The preparation method of low spatter and low smoke solder wire flux comprises the following steps:

[0050] Add 52% maleic rosin, 33% hydrogenated rosin, 0.2% phenyl glycol, and 0.2% propylene glycol butyl ether into a container, heat to 220°C, and stir until completely melted. When the composite rosin reaches a molten state, add 1.2% of an oily film-forming agent polyvinyl pyrrolidone / hexadecene copolymer, 5.4% of a film-forming aid dodecyl alcohol ester, 2% of a surfactant FSN-100 and 3% of FS-100, and 3% of Ciba antioxidant 1010 in sequence, and continue to heat and stir for 30 minutes. After the mixture is completely dissolved, continue to heat and stir for 20 minutes, stop the reaction, and cool to room temperature to obtain a solder wire flux with low spatter and less smoke.

[0051] The difference between Comparative Example 1 and Example 1 is that the gum rosin is replaced by maleic rosin, and the remaining steps are consistent with Example 1.

[0052] Comparative Example 2

[0053] This embodiment provides a low-spatter and low-smoke solder wire flux, which includes, by weight:

[0054] 59.3% gum rosin, 31% hydrogenated rosin and 0.3% phenyl glycol, 0.2% propylene glycol butyl ether, 2.5% FSN-100 and 3.4FSO-100, 3.3% Ciba antioxidant 1010

[0055] The preparation method of low spatter and low smoke solder wire flux comprises the following steps:

[0056] Add 53% gum rosin, 31% hydrogenated rosin, 0.3% phenyl glycol, and 0.2% propylene glycol butyl ether into a container, heat to 220°C, and stir until completely melted. When the composite rosin reaches a molten state, add 5.9% surfactants FSN-100 and FS-100, and 3.3% Ciba antioxidant 1010 in sequence, continue heating and stirring for 30 minutes, and continue heating and stirring for 20 minutes after the mixture is completely dissolved, stop the reaction, and cool to room temperature to obtain a solder wire flux with low spatter and less smoke.

[0057] The difference between Comparative Example 2 and Example 2 is that the film-forming agent trimethylsiloxysilicate and the film-forming aid turpentine are not added, and 6.3% of them are added to the composite rosin, and the remaining steps are consistent with Example 2.

[0058] The low spatter and low smoke solder wire flux obtained in Examples 1-3 and Comparative Examples 1-2 was subjected to expansion rate and spatter tests according to the test method specified in SJ / T11273-2002 of the Ministry of Industry and Information Technology of my country. The test results are shown in Table 1. The obtained test flux was subjected to surface insulation resistance (SIR) test. The test standard refers to "IPC TM-650 2.6.3.3B-2004 Surface Insulation Resistance, Soldering Flux". The test results are shown in Table 1. Figure 1-5 shown.

[0059] Table 1

[0060] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Expansion Rate % 85 87 84 74 76 Splash test Less (2) Less (5) Less (1) More (14) More (56)

[0061] As can be seen from Table 1, the expansion rates of Examples 1-3 of the present invention are ≥80%. Since the maleic rosin is replaced in Comparative Example 1 compared with Example 1, the expansion rate is reduced to 74%, and the number of spatters is also increased to 14. Since gum rosin and maleic rosin are different in chemical structure and physical properties. Gum rosin is a natural rosin, which usually has good thermal stability and chemical stability, which enables it to maintain good performance at high temperatures. Maleic rosin usually refers to rosin modified with maleic acid, and this modification may cause the stability of rosin at high temperatures to decrease, thereby affecting its performance. At the same time, there are differences in film-forming properties between gum rosin and maleic rosin. Gum rosin can usually form a relatively uniform and continuous protective film in the flux, which helps to improve the wettability of the welding surface and prevent oxidation. However, maleic rosin may have weaker film-forming properties due to its chemical modification, affecting its protective effect and wettability during welding. In a high-temperature welding environment, gum rosin produces less spatter and smoke due to its better thermal stability. In contrast, maleic rosin is more likely to decompose at high temperatures due to its modified structure, resulting in more spatter and smoke. Since maleic rosin may have poor film-forming properties and thermal stability, the expansion rate during welding is reduced and the amount of spatter increases.

[0062] In Comparative Example 2, the number of splashes increased sharply to 56 because the film-forming agent trimethylsiloxysilicate with excellent adhesion and weather resistance and the film-forming auxiliary agent turpentine were not added.

[0063] Trimethylsiloxysilicate was used as film former in Example 2, and this material has good thermal stability and excellent bonding properties. In the welding process, it can form a tough and continuous protective film in the welding area, which helps to reduce the volatilization and splashing of solder at high temperatures. This protective film can not only prevent the solder from evaporating too early, but also can suppress the material ejection (i.e. splashing) caused by thermodynamic instability in the welding process. On the other hand, turpentine was also used as a film former. Turpentine, due to its natural oily composition, can increase the fluidity and wettability of solder, and simultaneously helps film former to be more evenly distributed in the welding area, and strengthens the effect of the protective film of the whole solder. Like this, not only the welding quality is improved, but also the possibility of splashing is significantly reduced.

[0064] from Figure 1-3 It can be seen that the surface insulation resistance of the flux in Examples 1-3 after soldering is greater than 1×10 8 Ω, reaching the surface insulation resistance after welding ≥1×10 in IPC TM-650 2.6.3.3B-2004 standard 8 Ω requirements.

[0065] The surface insulation resistance of the flux of comparative example 1 decreased to 1×10 3This is because maleic rosin has two more carboxyl groups than ordinary gum rosin, and its reaction activity is improved, so the surface insulation resistance decreases.

[0066] The surface insulation resistance of two of the three channels of the flux in comparative example 2 also dropped to 1×10 3 Ω or less, indicating that increasing the percentage of rosin will increase the reaction activity, so the surface insulation resistance will decrease.

[0067] The present invention effectively reduces the smoke generated during the welding process by adopting high temperature resistant rosin. In addition, the added film-forming agent forms a hydrophobic coating on the surface of the solder wire, isolates the external water vapor, and enhances the moisture resistance of the solder wire. The oily film-forming agent used, such as trimethylsiloxysilicate, polyvinyl pyrrolidone / hexadecene copolymer, acrylic resin and dimethylsiloxane copolymer, has excellent adhesion and weather resistance. These film-forming agents can react rapidly at room temperature to form a solid mesh structure, enhance the hydrophobicity of the flux system, thereby reducing the splashing phenomenon of the solder wire during welding. The surfactant can effectively reduce the surface tension of the molten solder and promote wetting due to its special structure, but may leave hygroscopic residues after welding, so the amount used needs to be properly controlled.

[0068] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A low spatter and low smoke solder flux, characterized in that: The components include, by weight: 80-86.5% of rosin mixture, 0.9-1.4% of film former, 5-9.5% of film-forming aid, 5-8% of surfactant, 0.3-0.5% of compound solvent and 1.5-5.5% of antioxidant; The rosin mixture includes gum rosin and hydrogenated rosin, and the compound solvent includes phenyl glycol and propylene glycol butyl ether; The film former is trimethylsiloxysilicate; The film-forming aid is turpentine.

2. The low-spatter and low-smoke solder wire flux according to claim 1, characterized in that: The surfactant is one or more of FSN-100, FC-4430, FS-3100 and FSO-100.

3. The low spatter and low smoke solder wire flux according to claim 1, characterized in that: The antioxidant is at least one of Ciba antioxidant 1010 and antioxidant BHT.

4. A method for preparing a low-spatter and low-smoke solder wire flux as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Mix gum rosin and hydrogenated rosin in proportion, add compound solvent, and then heat to soften the rosin. Start stirring with a stirrer. When the composite rosin reaches a molten state, add a film-forming agent, a film-forming aid, a surfactant and an antioxidant. Continue heating and stirring. After the mixture is completely dissolved, continue heating and stirring for 20 minutes, stop the reaction, and cool to room temperature to obtain a solder wire flux.

5. The method for preparing the solder flux with low spatter and low smoke according to claim 4, characterized in that: The heating and stirring temperature is 200-220℃.

6. The method for preparing the solder flux with low spatter and low smoke according to claim 4, characterized in that: The heating and stirring speed is 500-1000 rpm.

7. The method for preparing the solder flux with low spatter and low smoke according to claim 4, characterized in that: The heating and stirring time is 1-2h.

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