A halogen-free and low-splash environmentally friendly soldering wire and its preparation method

Abstract

The present invention discloses a halogen-free and low-spatter environmental protection solder wire and a preparation method thereof, which relates to the technical field of electronic welding materials and is made of raw materials including the following in percentage by mass: 1-4 wt% of halogen-free flux, and the balance is lead-free solder; the lead-free solder is composed of the following components: Cu, Bi, Al, Ga, Ir, Ca, In, and Sn; the halogen-free flux includes the following components: (3,6-diaminoacridin-9-yl)boric acid, glycerol triricinoleate, 3-(N-morpholino)-2-hydroxypropanesulfonate sodium, 3-tris(hydroxymethyl)methylamine-2-hydroxypropanesulfonic acid, hydroxyethyl hexahydro-s-triazine, functional copolymer, surfactant, corrosion inhibitor, halogen-free activity enhancer, antioxidant, solvent, and rosin resin. This solder wire has a low spatter rate, high surface resistivity and solder joint reliability, no obvious corrosion, and good solderability.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic soldering materials, and particularly relates to a halogen-free low-spatter environmentally friendly solder wire and a preparation method thereof. Background Art

[0002] With the popularization and development of 5G communication technology and artificial intelligence, electronic products are constantly moving towards miniaturization, personalization, high precision and high reliability. The circuit integration amplitude has been greatly improved, the number of solder joints for welding has increased, and the reliability requirements for solder joints have become higher and higher, which also puts forward higher requirements for the quality of solder wire used for welding electronic components.

[0003] Solder wire is mainly used as a filler metal during welding or as a metal wire welding material for conducting electricity. It consists of two parts: a tin alloy and a soldering flux. During electronic soldering, the solder wire cooperates with an electric soldering iron. A high-quality electric soldering iron provides stable and continuous melting heat. The solder wire is added as a filler metal to the surface and gaps of electronic components to fix the electronic components and become the main component of the welding. Currently, commonly used solder wires basically contain halogens. These halogen-containing materials will produce dioxins when burned and can exist in the environment for many years, and even accumulate in organisms for life and cannot be discharged. It is in this situation that halogen-free environmentally friendly solder wire has emerged, and its appearance has attracted great attention in the industry. However, the halogen-free environmentally friendly solder wires on the market still have more or less technical defects such as a relatively high spatter rate during welding, which will affect the appearance of the soldered object and the safety of welding operators, the solderability needs to be further improved, the surface resistivity is relatively low, the corrosion is relatively large, there are microcracks on the surface of the solder joint, and the reliability needs to be further improved.

[0004] In order to solve the above problems, a Chinese invention patent with the authorization announcement number of CN103071944B discloses a halogen-free low-spatter solder wire and a preparation method thereof. The solder wire is composed of components by mass percentage: the solder is 97.4% - 98.2%, and the soldering flux is 1.8 - 2.6%. Among them, the solder is any one of Sn-0.7Cu, Sn-3.0Ag-0.5Cu, and Sn-0.3Ag-0.7Cu; the soldering flux is composed of components by mass percentage: rubber is 12 - 22%, organic acid is 6.5 - 8.5%, benzotriazole is 2%, imidazole substances are 2%, antioxidant oil is 3%, composite activator is 3.5 - 4.5%, and the balance is rosin. The preparation method is to first prepare the soldering flux according to the ratio, and then obtain the solder wire through processes such as wire extrusion, wire drawing, and wire winding. The characteristic indexes of the solder wire of this invention all meet the requirements of JIS-Z-3197 and IPC-TM-650 standards. After welding, the solder joints are bright, plump, have a small odor, less spatter, and are green and environmentally friendly. However, its spatter rate needs to be further reduced, and the surface resistivity and solder joint reliability need to be further improved.

[0005] It can be seen that developing a halogen-free low-spatter environmentally friendly solder wire with a low spatter rate, high surface resistivity and solder joint reliability, no obvious corrosiveness, and good solderability, as well as its preparation method, meets the market demand, has broad market value and application prospects, and is of great significance for promoting the development of the halogen-free solder wire field. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a halogen-free low-spatter environmentally friendly solder wire with a low spatter rate, high surface resistivity and solder joint reliability, no obvious corrosiveness, and good solderability, as well as its preparation method.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a halogen-free low-spatter environmentally friendly solder wire is made of raw materials including the following in mass percentages: 1-4 wt% of halogen-free flux, and the balance is lead-free solder; the lead-free solder is composed of the following components in weight percentages: 0.6-1 wt% of Cu, 0.01-0.03 wt% of Bi, 0.05-0.08 wt% of Al, 0.03-0.05 wt% of Ga, 0.001-0.003 wt% of Ir, 0.01-0.03 wt% of Ca, 0.005-0.01 wt% of In, and the balance is Sn; the halogen-free flux includes the following components in parts by weight: 2-4 parts of (3,6-diaminoacridin-9-yl)boronic acid, 1-2 parts of glycerol triricinoleate, 0.6-1 part of 3-(N-morpholino)-2-hydroxypropanesulfonate sodium, 0.8-1.5 parts of 3-tris(hydroxymethyl)methylamine-2-hydroxypropanesulfonic acid, 0.3-0.5 part of hydroxyethyl hexahydro-s-triazine, 1-3 parts of functional copolymer, 0.2-1 part of surfactant, 0.1-0.3 part of corrosion inhibitor, 0.5-2 parts of halogen-free activity enhancer, 0.1-0.3 part of antioxidant, 5-10 parts of solvent, and 70-85 parts of rosin resin; the functional copolymer includes structural units introduced by the following monomers: 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, and tricyclo[5.2.1.02,6]dec-8-yl methacrylate.

[0008] Preferably, the preparation method of the functional copolymer includes the following steps: adding 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, and initiator into a high-boiling solvent, stirring and reacting at 60-70 °C for 3-5 h in an inert gas atmosphere, then rotary evaporating to remove the solvent, dissolving the obtained crude product in water, taking the supernatant and placing it in a dialysis bag, dialyzing in deionized water for 20-30 h, and then rotary evaporating the solution in the dialysis bag to remove water to obtain the functional copolymer.

[0009] Preferably, the mass ratio of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate inner salt, N-trimethylolmethylacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, initiator, and high-boiling solvent is 1:(0.8 - 1.2):0.6:(0.3 - 0.5):(0.02 - 0.04):(10 - 15).

[0010] Preferably, the initiator is azobisisobutyronitrile; the high-boiling solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; the inert gas is any one of nitrogen, helium, neon, and argon.

[0011] Preferably, the surfactant is at least one of SURFYNOL 104 DPM, oleyl polyoxyethylene ether, DYNOL 604, and Surfynol 420.

[0012] Preferably, the corrosion inhibitor is at least one of benzotriazole, benzothiazole, and benzimidazole.

[0013] Preferably, the halogen-free activity enhancer is at least one of halogen-free activator ST-400 and halogen-free activator FR-500, provided by Shenzhen Jintenglong Industrial Co., Ltd.

[0014] Preferably, the antioxidant is at least one of antioxidant 1010 and antioxidant BHT.

[0015] Preferably, the solvent is one or more of tetrahydrofurfuryl alcohol, diethylene glycol monobutyl ether, and triethylene glycol butyl ether.

[0016] Preferably, the rosin resin is at least one of 125 rosin, 685 rosin, water-white hydrogenated rosin, and 150 rosin.

[0017] Another object of the present invention is to provide a method for preparing the halogen-free low-splash environmentally friendly soldering wire, comprising the following steps:

[0018] Step S1: Uniformly heat the rosin resin in the halogen-free flux formula to 165 - 175 °C. After it is completely dissolved and clarified, add the halogen-free activity enhancer, hydroxyethyl hexahydro-s-triazine, and functional copolymer in the halogen-free flux formula, and stir until all the materials are dissolved to obtain a compounding material. Cool it to 145 - 155 °C; Mix other components in the halogen-free flux formula evenly, add them to the compounding material, stir evenly at 145 - 155 °C, then filter the heated and melted solder paste through a 100-mesh filter screen and pour it into the flux barrel of the wire extrusion machine, keep it warm at 95 - 105 °C, and set the air pressure to 0.1 - 0.4 MPa;

[0019] Step S2: Select rod-shaped solder and install it on the wire extrusion machine. Set the wire extrusion temperature of the wire extrusion machine to 75 - 115 °C, the rotation speed of the wire extrusion machine to 290 - 330 rpm, adjust the wire extrusion hole diameter and the mass percentage content of the flux in proportion to the solder according to the wire diameter of φ10 mm, and then carry out wire extrusion;

[0020] Step S3: After the solder wire extruded in Step S2 undergoes three processes of large drawing, medium drawing, and small drawing, wind the wire to obtain the finished product of halogen-free low-spatter environmental protection solder wire.

[0021] Preferably, in the large drawing process in Step S3, the rotation speed of the wire drawing machine is 1100 - 1350 rpm, the drawing diameter is φ5 mm, and the wire drawing linear speed is 0.004 - 0.008 m / s; in the medium drawing process, the rotation speed of the wire drawing machine is 980 - 1280 rpm, the drawing diameter is φ2.16 mm, and the wire drawing linear speed is 0.45 - 0.95 m / s; in the small drawing process, the rotation speed of the wire drawing machine is 230 - 330 rpm, the drawing diameter is φ0.8 mm, and the wire drawing linear speed is 3 - 6 m / s.

[0022] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0023] (1) The preparation method of the halogen-free low-spatter environmental protection solder wire disclosed by the present invention has a simple process, convenient operation and control, high preparation efficiency and finished product qualification rate, low dependence on equipment, low energy consumption, low capital investment, low labor intensity, little impact on the environment, is suitable for continuous large-scale production, and has high popularization and application value.

[0024] (2)The halogen-free and low-splashing environmentally friendly soldering wire disclosed by the present invention, the lead-free solder is composed of the following components by weight percentage: Cu 0.6-1wt%, Bi 0.01-0.03wt%, Al 0.05-0.08wt%, Ga 0.03-0.05wt%, Ir 0.001-0.003wt%, Ca 0.01-0.03wt%, In 0.005-0.01wt%, and the balance is Sn; through the mutual cooperation of each component, the solder made not only has the characteristics of dense solder joints without microcracks, but also has advantages in terms of spreading rate, wettability, mechanical properties and other reliability aspects; among them, expensive silver is not added, effectively improving the cost performance.

[0025] (3)The halogen-free and low-splashing environmentally friendly soldering wire disclosed by the present invention, the halogen-free flux includes the following components by weight: 2-4 parts of (3,6-diaminoacridin-9-yl)boric acid, 1-2 parts of glycerol triricinoleate, 0.6-1 part of 3-(N-morpholino)-2-hydroxypropanesulfonate, 0.8-1.5 parts of 3-tris(hydroxymethyl)methylamine-2-hydroxypropanesulfonic acid, 0.3-0.5 part of hydroxyethyl hexahydro-s-triazine, 1-3 parts of functional copolymer, 0.2-1 part of surfactant, 0.1-0.3 part of corrosion inhibitor, 0.5-2 parts of halogen-free activity enhancer, 0.1-0.3 part of antioxidant, 5-10 parts of solvent, 70-85 parts of rosin resin; the functional copolymer includes the structural units introduced by the following monomers: 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, methyl acrylate tricyclo[5.2.1.02,6]dec-8-yl ester. Through the mutual cooperation of each component, the splash rate can be effectively reduced, the solderability and the reliability of the solder joints can be improved, and in cooperation with the solder, the surface resistivity can be effectively increased, making the made soldering wire have no obvious corrosion.

[0026] (4)The halogen-free and low-splashing environmentally friendly soldering wire disclosed by the present invention is halogen-free and lead-free, with better environmental performance and safer to use; through the reasonable selection of the types and dosage ratios of each component and component, the solderability can be improved, the welding efficiency can be increased, there is less splash during welding, and subsequent corrosion can also be reduced. Detailed implementation mode

[0027] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations. Example 1

[0028] A halogen-free and low-splash environmentally friendly solder wire is made of raw materials including the following in mass percentages: 1 wt% of halogen-free flux, and the balance is lead-free solder; the lead-free solder is composed of the following components in weight percentages: 0.6 wt% of Cu, 0.01 wt% of Bi, 0.05 wt% of Al, 0.03 wt% of Ga, 0.001 wt% of Ir, 0.01 wt% of Ca, 0.005 wt% of In, and the balance is Sn; the halogen-free flux includes the following components in parts by weight: 2 parts of (3,6-diaminoacridin-9-yl)boric acid, 1 part of glycerol triricinoleate, 0.6 part of 3-(N-morpholino)-2-hydroxypropanesulfonate sodium, 0.8 part of 3-tris(hydroxymethyl)methylamine-2-hydroxypropanesulfonic acid, 0.3 part of hydroxyethyl hexahydro-s-triazine, 1 part of functional copolymer, 0.2 part of surfactant, 0.1 part of corrosion inhibitor, 0.5 part of halogen-free activity enhancer, 0.1 part of antioxidant, 5 parts of solvent, and 70 parts of rosin resin; the functional copolymer includes structural units introduced by the following monomers: 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, and tricyclo[5.2.1.02,6]dec-8-yl methacrylate.

[0029] The preparation method of the functional copolymer includes the following steps: adding 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, and initiator into a high-boiling solvent, stirring and reacting at 60 °C for 3 h in an inert gas atmosphere, then rotary evaporating to remove the solvent, dissolving the obtained crude product in water, taking the supernatant and placing it in a dialysis bag, dialyzing in deionized water for 20 h, and then rotary evaporating the solution in the dialysis bag to remove water to obtain the functional copolymer; the mass ratio of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, initiator, and high-boiling solvent is 1:0.8:0.6:0.3:0.02:10; the initiator is azobisisobutyronitrile; the high-boiling solvent is N,N-dimethylformamide; the inert gas is nitrogen; through GPC test, the M n of the obtained functional copolymer is measured to be 16370 g / mol, and M W / M n= 1.357; Through elemental analysis and weight change calculation, the mass ratio of the structural units introduced by 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-trimethylolmethylacrylamide, acrylamide, and tricyclo[5.2.1.02,6]dec-8-yl methacrylate in the functional copolymer is 0.99:0.78:0.59:0.27.

[0030] The surfactant is SURFYNOL 104 DPM; the corrosion inhibitor is benzotriazole; the halogen-free activity enhancer is the halogen-free activator ST-400 provided by Shenzhen Jintenglong Industrial Co., Ltd.; the antioxidant is antioxidant 1010; the solvent is tetrahydrofurfuryl alcohol; the rosin resin is 125 rosin.

[0031] A preparation method of the halogen-free low-splash environmentally friendly solder wire includes the following steps:

[0032] Step S1: Uniformly heat the rosin resin in the halogen-free flux formula to 165 °C. After it is completely dissolved and clarified, add the halogen-free activity enhancer, hydroxyethyl hexahydro-s-triazine, and functional copolymer in the halogen-free flux formula, and stir until all the materials are dissolved to obtain a compounded material, then cool it to 145 °C; Mix the other components in the halogen-free flux formula evenly, add them to the compounded material, stir evenly at 145 °C, then filter the heated and melted solder paste through a 100-mesh filter screen and pour it into the flux barrel of the wire extruder and keep it at 95 °C, and set the air pressure to 0.1 MPa;

[0033] Step S2: Select rod-shaped solder and install it on the wire extruder. Set the wire extrusion temperature of the wire extruder to 75 °C, the wire extrusion speed of the wire extruder to 290 rpm, adjust the wire extrusion aperture and the mass percentage content of the flux in proportion to the solder according to the wire diameter of φ10 mm, and then perform wire extrusion;

[0034] Step S3: After the solder wire extruded in Step S2 undergoes three processes of large drawing, medium drawing, and small drawing, wind the wire to obtain the finished product of the halogen-free low-splash environmentally friendly solder wire.

[0035] In the large drawing process in Step S3, the rotation speed of the wire drawing machine is 1100 rpm, the drawing diameter is φ5 mm, and the wire drawing speed is 0.004 m / s; in the medium drawing process, the rotation speed of the wire drawing machine is 980 rpm, the drawing diameter is φ2.16 mm, and the wire drawing speed is 0.45 m / s; in the small drawing process, the rotation speed of the wire drawing machine is 230 rpm, the drawing diameter is φ0.8 mm, and the wire drawing speed is 3 m / s. Example 2

[0036] A halogen-free and low-splashing environmentally friendly soldering wire is made of raw materials including the following in mass percentages: 2 wt% of halogen-free flux, and the balance is lead-free solder; the lead-free solder is composed of the following components in weight percentages: 0.7 wt% of Cu, 0.015 wt% of Bi, 0.06 wt% of Al, 0.035 wt% of Ga, 0.0015 wt% of Ir, 0.015 wt% of Ca, 0.006 wt% of In, and the balance is Sn; the halogen-free flux includes the following components in parts by weight: 2.5 parts of (3,6-diaminoacridin-9-yl)boronic acid, 1.2 parts of glycerol triricinoleate, 0.7 part of 3-(N-morpholino)-2-hydroxypropanesulfonate sodium, 1 part of 3-tris(hydroxymethyl)methylamine-2-hydroxypropanesulfonic acid, 0.35 part of hydroxyethyl hexahydro-s-triazine, 1.5 parts of functional copolymer, 0.4 part of surfactant, 0.15 part of corrosion inhibitor, 0.9 part of halogen-free activity enhancer, 0.15 part of antioxidant, 6 parts of solvent, and 75 parts of rosin resin; the functional copolymer includes structural units introduced by the following monomers: 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, and tricyclo[5.2.1.02,6]dec-8-yl methacrylate.

[0037] The preparation method of the functional copolymer includes the following steps: adding 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, and initiator into a high-boiling solvent, stirring and reacting at 63 °C for 3.5 h under an inert gas atmosphere, then rotary evaporating to remove the solvent, dissolving the obtained crude product in water, taking the supernatant and placing it in a dialysis bag, dialyzing in deionized water for 23 h, and then rotary evaporating the solution in the dialysis bag to remove water to obtain the functional copolymer; the mass ratio of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, initiator, and high-boiling solvent is 1:0.9:0.6:0.35:0.025:12; the initiator is azobisisobutyronitrile; the high-boiling solvent is N,N-dimethylacetamide; the inert gas is helium.

[0038] The surfactant is oleyl polyoxyethylene ether; the corrosion inhibitor is benzothiazole; the halogen-free activity enhancer is halogen-free activator FR-500 provided by Shenzhen Jintenglong Industry Co., Ltd.; the antioxidant is antioxidant BHT; the solvent is diethylene glycol monobutyl ether; the rosin resin is 685 rosin.

[0039] A preparation method of the halogen-free low-spatter environmentally friendly solder wire includes the following steps:

[0040] Step S1: Uniformly heat the rosin resin in the halogen-free flux formula to 168°C. After it is completely melted and clarified, add the halogen-free activity enhancer, hydroxyethyl hexahydro-s-triazine, and functional copolymer in the halogen-free flux formula, and stir until all the materials are dissolved to obtain a compounding material, then cool it to 148°C; mix the other components in the halogen-free flux formula evenly, add them to the compounding material, stir evenly at 148°C, then filter the heated and melted solder paste through a 100-mesh filter screen and pour it into the flux barrel of the wire extruder for heat preservation at 98°C, and set the air pressure to 0.2 MPa;

[0041] Step S2: Select a rod-shaped solder and install it on the wire extruder. Set the wire extrusion temperature of the wire extruder to 85°C, the wire extrusion speed of the wire extruder to 300 rpm, adjust the wire extrusion aperture and the mass percentage content of the flux in proportion to the solder according to the wire diameter of φ10 mm, and then perform wire extrusion;

[0042] Step S3: Subject the solder wire extruded in Step S2 to three processes of large drawing, medium drawing, and small drawing, and then wind the wire to obtain the finished product of the halogen-free low-spatter environmentally friendly solder wire.

[0043] In the large drawing process in Step S3, the rotation speed of the wire drawing machine is 1150 rpm, the drawing diameter is φ5 mm, and the wire drawing speed is 0.006 m / s; in the medium drawing process, the rotation speed of the wire drawing machine is 1080 rpm, the drawing diameter is φ2.16 mm, and the wire drawing speed is 0.55 m / s; in the small drawing process, the rotation speed of the wire drawing machine is 260 rpm, the drawing diameter is φ0.8 mm, and the wire drawing speed is 4 m / s. Example 3

[0044] A halogen-free and low-splashing environmentally friendly solder wire is made from raw materials in the following mass percentages: halogen-free flux 2.5 wt%, and the balance is lead-free solder; the lead-free solder is composed of the following components in weight percentages: Cu 0.8 wt%, Bi 0.02 wt%, Al 0.065 wt%, Ga 0.04 wt%, Ir 0.002 wt%, Ca 0.02 wt%, In 0.0075 wt%, and the balance is Sn; the halogen-free flux includes the following components by weight: (3,6-diaminoacridin-9-yl)boronic acid 3 parts, glycerol triricinoleate 1.5 parts, 3-(N-morpholino)-2-hydroxypropanesulfonate sodium 0.8 parts, 3-tris(hydroxymethyl)methylamine-2-hydroxypropanesulfonic acid 1.2 parts, hydroxyethyl hexahydro-s-triazine 0.4 parts, functional copolymer 2 parts, surfactant 0.7 parts, corrosion inhibitor 0.2 parts, halogen-free activity enhancer 1.4 parts, antioxidant 0.2 parts, solvent 7.5 parts, rosin resin 79 parts; the functional copolymer includes structural units introduced by the following monomers: 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, methyl acrylate tricyclo[5.2.1.02,6]dec-8-yl ester.

[0045] The preparation method of the functional copolymer includes the following steps: adding 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, methyl acrylate tricyclo[5.2.1.02,6]dec-8-yl ester, and initiator into a high-boiling solvent, stirring and reacting at 65 °C for 4 h in an inert gas atmosphere, then rotary evaporating to remove the solvent, dissolving the obtained crude product in water, taking the supernatant and placing it in a dialysis bag, dialyzing in deionized water for 25 h, and then rotary evaporating the solution in the dialysis bag to remove water to obtain the functional copolymer; the mass ratio of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, methyl acrylate tricyclo[5.2.1.02,6]dec-8-yl ester, initiator, and high-boiling solvent is 1:1:0.6:0.4:0.03:13; the initiator is azobisisobutyronitrile; the high-boiling solvent is N-methylpyrrolidone; the inert gas is neon.

[0046] The surfactant is DYNOL 604; the corrosion inhibitor is benzimidazole; the halogen-free activity enhancer is halogen-free activator ST-400 provided by Shenzhen Jintenglong Industry Co., Ltd.; the antioxidant is antioxidant 1010; the solvent is triethylene glycol butyl ether; the rosin resin is water-white hydrogenated rosin.

[0047] A preparation method of the halogen-free low-spatter environmentally friendly solder wire comprises the following steps:

[0048] Step S1: Uniformly heat the rosin resin in the halogen-free flux formula to 170°C. After it is completely dissolved and clarified, add the halogen-free activity enhancer, hydroxyethyl hexahydro-s-triazine, and functional copolymer in the halogen-free flux formula, and stir until all the materials are dissolved to obtain a compounding material, then cool it to 150°C; mix the other components in the halogen-free flux formula evenly, add them to the compounding material, stir evenly at 150°C, then filter the heated and melted solder paste through a 100-mesh filter screen and pour it into the flux barrel of the wire extruder for heat preservation at 100°C, and set the air pressure to 0.25 MPa;

[0049] Step S2: Select a rod-shaped solder and install it on the wire extruder. Set the wire extrusion temperature of the wire extruder to 95°C and the wire extrusion speed to 315 rpm. Adjust the wire extrusion aperture and the mass percentage content of the flux in proportion to the solder according to the wire diameter of φ10 mm, and then carry out wire extrusion;

[0050] Step S3: Subject the solder wire extruded in Step S2 to three processes of large drawing, medium drawing, and small drawing, and then wind the wire to obtain the finished product of the halogen-free low-spatter environmentally friendly solder wire.

[0051] In the large drawing process in Step S3, the rotation speed of the wire drawing machine is 1250 rpm, the drawing diameter is φ5 mm, and the wire drawing speed is 0.006 m / s; in the medium drawing process, the rotation speed of the wire drawing machine is 1180 rpm, the drawing diameter is φ2.16 mm, and the wire drawing speed is 0.75 m / s; in the small drawing process, the rotation speed of the wire drawing machine is 300 rpm, the drawing diameter is φ0.8 mm, and the wire drawing speed is 4.5 m / s. Example 4

[0052] A halogen-free and low-splash environmentally friendly solder wire is made of raw materials including the following in mass percentages: 3.5 wt% of halogen-free flux, and the balance is lead-free solder; the lead-free solder is composed of the following components in weight percentages: 0.95 wt% of Cu, 0.025 wt% of Bi, 0.075 wt% of Al, 0.045 wt% of Ga, 0.0025 wt% of Ir, 0.025 wt% of Ca, 0.009 wt% of In, and the balance is Sn; the halogen-free flux includes the following components in parts by weight: 3.5 parts of (3,6-diaminoacridin-9-yl)boronic acid, 1.8 parts of tritroglycerol rosinate, 0.9 part of 3-(N-morpholino)-2-hydroxypropanesulfonate sodium, 1.4 parts of 3-tris(hydroxymethyl)methylamine-2-hydroxypropane sulfonic acid, 0.45 part of hydroxyethyl hexahydro-s-triazine, 2.5 parts of functional copolymer, 0.9 part of surfactant, 0.25 part of corrosion inhibitor, 1.8 parts of halogen-free activity enhancer, 0.25 part of antioxidant, 9 parts of solvent, and 83 parts of rosin resin; the functional copolymer includes structural units introduced by the following monomers: 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, and tricyclo[5.2.1.02,6]dec-8-yl methacrylate.

[0053] The preparation method of the functional copolymer comprises the following steps: adding 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-trimethylolmethylacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, and an initiator into a high-boiling solvent, stirring and reacting at 68 °C for 4.5 h in an inert gas atmosphere, then rotary evaporating to remove the solvent, dissolving the obtained crude product in water, taking the supernatant and placing it in a dialysis bag, dialyzing in deionized water for 28 h, and then rotary evaporating the solution in the dialysis bag to remove water to obtain the functional copolymer; the mass ratio of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-trimethylolmethylacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, the initiator, and the high-boiling solvent is 1:1.1:0.6:0.45:0.035:14; the initiator is azobisisobutyronitrile; the high-boiling solvent is a mixture of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone in a mass ratio of 1:1:2; the inert gas is argon; the surfactant is a mixture of SURFYNOL 104 DPM, polyoxyethylene oleyl ether, DYNOL 604, and Surfynol 420 in a mass ratio of 1:2:2:3; the corrosion inhibitor is a mixture of benzotriazole, benzothiazole, and benzimidazole in a mass ratio of 1:2:1; the halogen-free activity enhancer is a mixture of halogen-free activator ST-400 and halogen-free activator FR-500 in a mass ratio of 3:5; the antioxidant is a mixture of antioxidant 1010 and antioxidant BHT in a mass ratio of 1:3; the solvent is a mixture of tetrahydrofurfuryl alcohol, diethylene glycol monobutyl ether, and triethylene glycol butyl ether in a mass ratio of 1:1:1; the rosin resin is a mixture of 125 rosin, 685 rosin, water-white hydrogenated rosin, and 150 rosin in a mass ratio of 1:4:3:1.

[0054] A preparation method of the halogen-free low-splash environmentally friendly soldering wire comprises the following steps:

[0055] Step S1: Uniformly heat the rosin resin in the halogen-free flux formulation to 173 °C. After it is completely dissolved and clarified, add the halogen-free activity enhancer, hydroxyethyl hexahydro-s-triazine, and the functional copolymer in the halogen-free flux formulation, stir until all the materials are dissolved to obtain a compounded material, and cool it to 153 °C; mix the other components in the halogen-free flux formulation evenly, add them to the compounded material, stir evenly at 153 °C, then filter the heated and melted solder paste through a 100-mesh filter screen and pour it into the flux barrel of the wire extruder to keep it warm at 103 °C, and set the air pressure to 0.35 MPa;

[0056] Step S2: Select rod-shaped solder and install it on the wire extrusion machine. Set the wire extrusion temperature of the wire extrusion machine to 110 °C and the rotational speed of the wire extrusion machine to 320 rpm. Adjust the wire extrusion aperture and the mass percentage content of the soldering flux in proportion to the solder according to a wire diameter of φ10 mm, and then perform wire extrusion;

[0057] Step S3: Subject the solder wire extruded in Step S2 to three processes of large drawing, medium drawing, and small drawing, and then wind the wire to obtain a halogen-free and low-spatter environmentally friendly solder wire product.

[0058] In the large drawing process described in Step S3, the rotational speed of the wire drawing machine is 1330 rpm, the wire drawing diameter is φ5 mm, and the wire drawing speed is 0.0075 m / s; in the medium drawing process, the rotational speed of the wire drawing machine is 1250 rpm, the wire drawing diameter is φ2.16 mm, and the wire drawing speed is 0.9 m / s; in the small drawing process, the rotational speed of the wire drawing machine is 320 rpm, the wire drawing diameter is φ0.8 mm, and the wire drawing speed is 5.5 m / s. Example 5

[0059] A halogen-free and low-spatter environmentally friendly solder wire is made from raw materials including the following in mass percentages: 4 wt% of halogen-free soldering flux, and the balance is lead-free solder; the lead-free solder is composed of the following components in weight percentages: 1 wt% of Cu, 0.03 wt% of Bi, 0.08 wt% of Al, 0.05 wt% of Ga, 0.003 wt% of Ir, 0.03 wt% of Ca, 0.01 wt% of In, and the balance is Sn; the halogen-free soldering flux includes the following components in parts by weight: 4 parts of (3,6-diaminoacridin-9-yl)boronic acid, 2 parts of glycerol triricinoleate, 1 part of 3-(N-morpholino)-2-hydroxypropanesulfonate sodium, 1.5 parts of 3-tris(hydroxymethyl)methylamine-2-hydroxypropanesulfonic acid, 0.5 part of hydroxyethyl hexahydro-s-triazine, 3 parts of functional copolymer, 1 part of surfactant, 0.3 part of corrosion inhibitor, 2 parts of halogen-free activity enhancer, 0.3 part of antioxidant, 10 parts of solvent, and 85 parts of rosin resin; the functional copolymer includes structural units introduced by the following monomers: 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, and tricyclo[5.2.1.02,6]dec-8-yl methacrylate.

[0060] The preparation method of the functional copolymer comprises the following steps: adding 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-trimethylolmethylacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, and an initiator into a high-boiling solvent, stirring and reacting at 70 °C for 5 h under an inert gas atmosphere, then rotary evaporating to remove the solvent, dissolving the obtained crude product in water, taking the supernatant and placing it in a dialysis bag, dialyzing in deionized water for 30 h, and then rotary evaporating the solution in the dialysis bag to remove water to obtain the functional copolymer; the mass ratio of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-trimethylolmethylacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, the initiator, and the high-boiling solvent is 1:1.2:0.6:0.5:0.04:15; the initiator is azobisisobutyronitrile; the high-boiling solvent is N,N-dimethylformamide; the inert gas is nitrogen.

[0061] The surfactant is SURFYNOL 104 DPM; the corrosion inhibitor is benzothiazole; the halogen-free activity enhancer is halogen-free activator ST-400 provided by Shenzhen Jintenglong Industry Co., Ltd.; the antioxidant is antioxidant 1010; the solvent is tetrahydrofurfuryl alcohol; the rosin resin is 150 rosin.

[0062] A preparation method of the halogen-free low-spatter environmentally friendly soldering wire comprises the following steps:

[0063] Step S1: Uniformly heat the rosin resin in the halogen-free flux formulation to 175 °C. After it is completely dissolved and clarified, add the halogen-free activity enhancer, hydroxyethyl hexahydro-s-triazine, and the functional copolymer in the halogen-free flux formulation, stir until all the materials are dissolved to obtain a compounded material, and cool it to 155 °C; mix the other components in the halogen-free flux formulation evenly, add them to the compounded material, stir evenly at 155 °C, then filter the heated and melted solder paste through a 100-mesh filter screen and pour it into the flux barrel of the wire extruder, keep it at 105 °C, and set the air pressure to 0.4 MPa;

[0064] Step S2: Select a rod-shaped solder and install it on the wire extruder. Set the wire extrusion temperature of the wire extruder to 115 °C, the wire extrusion speed to 330 rpm, adjust the wire extrusion aperture and the mass percentage content of the flux in proportion to the solder according to a wire diameter of φ10 mm, and then perform wire extrusion;

[0065] Step S3: Subject the soldering wire extruded in Step S2 to three processes of large drawing, medium drawing, and small drawing, and then wind the wire to obtain the finished product of the halogen-free low-spatter environmentally friendly soldering wire.

[0066] During the large-drawing process described in step S3, the rotational speed of the wire drawing machine is 1350 rpm, the wire drawing diameter is φ5 mm, and the wire drawing speed is 0.008 m / s; during the medium-drawing process, the rotational speed of the wire drawing machine is 1280 rpm, the wire drawing diameter is φ2.16 mm, and the wire drawing speed is 0.95 m / s; during the small-drawing process, the rotational speed of the wire drawing machine is 330 rpm, the wire drawing diameter is φ0.8 mm, and the wire drawing speed is 6 m / s.

[0067] Comparative Example 1

[0068] A halogen-free, low-spatter, environmentally friendly solder wire and its preparation method are basically the same as those in Example 1, except that Ir and the functional copolymer are not added.

[0069] Comparative Example 2

[0070] A halogen-free, low-spatter, environmentally friendly solder wire and its preparation method are basically the same as those in Example 1, except that In and (3,6-diaminoacridin-9-yl)boric acid are not added.

[0071] To further illustrate the beneficial technical effects of the halogen-free, low-spatter, environmentally friendly solder wires involved in the embodiments of the present invention, relevant performance tests were conducted on the halogen-free, low-spatter, environmentally friendly solder wires involved in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1, and the test methods are as follows:

[0072] (1) Expansion rate: Tested with reference to Section 3.9 of SJ2660-1986.

[0073] (2) Copper plate corrosion and surface insulation resistance: Tested with reference to SJ / T 11389-2019.

[0074] (3) Spatter amount: Tested with reference to SJ / T 11390-2019.

[0075] (4) Solder joint fracture strength: Tested with reference to SJ / T 11390-2019.

[0076] Table 1

[0077]

[0078] As can be seen from Table 1, the halogen-free, low-spatter, environmentally friendly solder wires involved in the embodiments of the present invention have better solderability and solder joint reliability, lower spatter and corrosiveness, and higher surface insulation resistance than the products of the comparative examples. The addition of Ir, In, (3,6-diaminoacridin-9-yl)boric acid, and the functional copolymer is beneficial to improving the above properties.

[0079] The above embodiments are only used to illustrate the technical concept and features of the present invention. The purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and it should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A halogen-free and low-splash environmentally friendly soldering wire, characterized in that, It is made from raw materials including the following in mass percentages: 1-4 wt% of halogen-free flux, and the balance is lead-free solder; the lead-free solder is composed of the following components in weight percentages: 0.6-1 wt% of Cu, 0.01-0.03 wt% of Bi, 0.05-0.08 wt% of Al, 0.03-0.05 wt% of Ga, 0.001-0.003 wt% of Ir, 0.01-0.03 wt% of Ca, 0.005-0.01 wt% of In, and the balance is Sn; the halogen-free flux includes the following components in parts by weight: 2-4 parts of (3,6-diaminoacridin-9-yl)boronic acid, 1-2 parts of glycerol triricinoleate, 0.6-1 part of 3-(N-morpholino)-2-hydroxypropanesulfonate sodium, 0.8-1.5 parts of 3-tris(hydroxymethyl)methylamine-2-hydroxypropanesulfonic acid, 0.3-0.5 part of hydroxyethyl hexahydro-s-triazine, 1-3 parts of functional copolymer, 0.2-1 part of surfactant, 0.1-0.3 part of corrosion inhibitor, 0.5-2 parts of halogen-free activity enhancer, 0.1-0.3 part of antioxidant, 5-10 parts of solvent, and 70-85 parts of rosin resin; the functional copolymer includes structural units introduced by the following monomers: 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, and tricyclo[5.2.1.02,6]dec-8-yl methacrylate; The preparation method of the functional copolymer includes the following steps: adding 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, and initiator into a high-boiling solvent, stirring and reacting at 60-70 °C for 3-5 h in an inert gas atmosphere, then rotary evaporating to remove the solvent, dissolving the obtained crude product in water, taking the supernatant and placing it in a dialysis bag, dialyzing in deionized water for 20-30 h, and then rotary evaporating the solution in the dialysis bag to remove water to obtain the functional copolymer; The mass ratio of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, N-tris(hydroxymethyl)methacrylamide, acrylamide, tricyclo[5.2.1.02,6]dec-8-yl methacrylate, initiator, and high-boiling solvent is 1:(0.8-1.2):0.6:(0.3-0.5):(0.02-0.04):(10-15).

2. The halogen-free and low-splash environmentally friendly soldering wire according to claim 1, wherein, The initiator is azobisisobutyronitrile; the high-boiling solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; the inert gas is any one of nitrogen, helium, neon, and argon.

3. The halogen-free and low-splash environmentally friendly soldering wire according to claim 1, characterized in that, The surfactant is at least one of SURFYNOL 104 DPM, oleyl polyoxyethylene ether, DYNOL 604, and Surfynol 420; the corrosion inhibitor is at least one of benzotriazole, benzothiazole, and benzimidazole.

4. The halogen-free and low-splash environmentally friendly soldering wire according to claim 1, wherein The halogen-free activity enhancer is at least one of halogen-free activator ST-400 and halogen-free activator FR-500.

5. The halogen-free and low-splash environmental protection solder wire according to claim 1, wherein The antioxidant is at least one of antioxidant 1010 and antioxidant BHT.

6. The halogen-free and low-splash environmentally friendly soldering wire according to claim 1, characterized in that, The solvent is one or more of tetrahydrofurfuryl alcohol, diethylene glycol monobutyl ether, and triethylene glycol butyl ether; the rosin resin is at least one of 125 rosin, 685 rosin, water-white hydrogenated rosin, and 150 rosin.

7. A preparation method of the halogen-free and low-splash environmental protection soldering wire according to any one of claims 1-6, characterized in that, It includes the following steps: Step S1: Uniformly heat the rosin resin in the halogen-free flux formula to 165 - 175 °C. After it is completely dissolved and clarified, add the halogen-free activity enhancer, hydroxyethyl hexahydro-s-triazine, and functional copolymer in the halogen-free flux formula, and stir until all the materials are dissolved to obtain a compounded material. Cool it to 145 - 155 °C; mix the other components in the halogen-free flux formula evenly, add them to the compounded material, stir evenly at 145 - 155 °C, then filter the heated and melted solder paste through a 100-mesh filter screen and pour it into the flux barrel of the wire extruder, keep it warm at 95 - 105 °C, and set the air pressure to 0.1 - 0.4 MPa; Step S2: Select rod-shaped solder and install it on the wire extruder. Set the wire extrusion temperature of the wire extruder to 75 - 115 °C and the rotation speed of the wire extruder to 290 - 330 rpm. Adjust the wire extrusion hole diameter and the mass percentage content of the flux in proportion to the solder according to the wire diameter of φ10 mm, and then perform wire extrusion; Step S3: After the solder wire extruded in Step S2 undergoes three processes of large drawing, medium drawing, and small drawing, wind the wire to obtain the finished product of halogen-free low-spatter environmental protection solder wire.

8. The preparation method of the halogen-free and low-splash environmental protection soldering wire according to claim 7, characterized in that, In the large drawing process in Step S3, the rotation speed of the wire drawing machine is 1100 - 1350 rpm, the drawing diameter is φ5 mm, and the wire drawing speed is 0.004 - 0.008 m / s; in the medium drawing process, the rotation speed of the wire drawing machine is 980 - 1280 rpm, the drawing diameter is φ2.16 mm, and the wire drawing speed is 0.45 - 0.95 m / s; in the small drawing process, the rotation speed of the wire drawing machine is 230 - 330 rpm, the drawing diameter is φ0.8 mm, and the wire drawing speed is 3 - 6 m / s.

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