Protective glue material for preventing oxidation of welding spots of copper and aluminum pipes and preparation method of protective glue material
By using a protective adhesive composed of polyether-modified MQ resin and modified titanium dioxide, the problem of easy corrosion of copper-aluminum pipe weld joints in humid environments was solved, and the high-temperature stability and mechanical properties of the weld joints were improved.
Patent Information
- Application Number
- CN202511591589.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-03
- Publication Date
- 2026-01-09
AI Technical Summary
Existing copper-aluminum pipe weld joints are prone to galvanic corrosion in humid environments. Traditional protective adhesives have poor weather resistance, are incompatible with copper pipes, and have poor thermal stability, leading to weld joint failure.
Using polyether-modified MQ resin, modified titanium dioxide, N-hexadecyl diethanolamine and organic acid corrosion inhibitors, a high-temperature resistant and hydrophobic protective adhesive is formed through hydrosilylation reaction and surface modification, which enhances the oxidation resistance of the solder joint.
It improves the high-temperature stability, water resistance, and mechanical properties of the solder joints, extends their service life, and reduces the risk of electrochemical corrosion.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of metal protective glue preparation, and particularly relates to a protective glue material for preventing oxidation of a copper-aluminum pipe welding point and a preparation method thereof. BACKGROUND
[0002] Copper and its alloys have excellent physical properties and are widely used in various industrial fields. However, the copper resources in China are insufficient to meet market demand. China is rich in bauxite resources, and aluminum has the advantages of low price, good thermal conductivity, corrosion resistance, high strength, and easy processing. Therefore, using copper-aluminum pipes instead of all-copper pipes has obvious advantages. Currently, copper-aluminum pipe connection mainly adopts mechanical connection and welding. The mechanical connection process is simple, but has problems such as poor mechanical properties and poor air tightness. Therefore, welding is a commonly used copper-aluminum pipe connection method. However, the welding point is easily subject to galvanic corrosion when exposed to a humid environment, which leads to welding point failure and reduces the safety service performance of the welding point. Therefore, the copper-aluminum welding point needs to be protected against oxidation, but traditional copper-aluminum welding point oxidation protection faces many problems, such as poor weather resistance, easy cracking failure under thermal expansion and contraction, incompatibility between the protective glue and the copper pipe, easy generation of copper green, and poor high-temperature resistance.
[0003] Therefore, it is of great significance to develop a protective glue material for preventing oxidation of a copper-aluminum pipe welding point. SUMMARY
[0004] The present application aims to provide a protective glue material for preventing oxidation of a copper-aluminum pipe welding point and a preparation method thereof to solve the problems in the prior art.
[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions. A preparation method of a protective glue material for preventing oxidation of a copper-aluminum pipe welding point, comprising the following steps: S1: adding MQ resin and allyl polyoxyethylene methyl ether into toluene, stirring until uniform, adding a platinum catalyst, heating at 80-90 DEG C for 3-5 h, rotary evaporation, washing and collecting to obtain a polyether modified MQ resin; S2: mixing polyoxypropylene glycol with toluene-2, 4-diisocyanate, heating at 50-60 DEG C for 30-60 min, adding N-n-hexadecyl diethanolamine, and heating to 75-85 DEG C for 3-5 h to obtain a prepolymer; S3: stirring the prepolymer, 1, 4-butanediol and polyether modified MQ resin until uniform, then adding t-butyl p-diphenol, modified titanium dioxide, polyoxypropylene triol and organic acid corrosion inhibitor, stirring until uniform, and removing air bubbles under vacuum to obtain a welding point protective glue.
[0006] Further, in step S1, the platinum catalyst is Karstedt catalyst; the mass ratio of the MQ resin, allyl polyoxyethylene methyl ether and platinum catalyst is (40-60):(20-30):(0.005-0.02).
[0007] Further, in step S1, the preparation method of the MQ resin is as follows: glacial acetic acid, tetramethyldisiloxane are added into concentrated sulfuric acid, stirring at 30-40℃ for 30-60min, methyl triethoxysilane is added, heating at 50-60℃ for 2-4h, cooling at room temperature, adding sodium bicarbonate to adjust pH to 7, removing the acid water layer, adding sodium sulfate to the organic layer to remove water, rotary evaporation, vacuum drying for 2-4h to obtain the MQ resin.
[0008] Further, in the preparation process of the MQ resin, the mass ratio of glacial acetic acid, tetramethyldisiloxane, concentrated sulfuric acid and methyl triethoxysilane is (65-75):(14-18):(0.5-1):(35-40).
[0009] Further, in step S2, the mass ratio of polyoxypropylene glycol, toluene-2,4-diisocyanate and N-hexadecyl diethanolamine is 100:(25-35):(20-25).
[0010] Further, in step S3, the preparation method of the modified titanium dioxide is as follows: the pretreated titanium dioxide, hexamethyldisilazane and N,N-dimethylformamide are placed in a flask, stirring and mixing, heating at 90-110℃ for 2-4h, washing, vacuum drying for 4-6h to obtain the modified titanium dioxide. In the preparation process of the modified titanium dioxide, the mass ratio of pretreated titanium dioxide, hexamethyldisilazane and N,N-dimethylformamide is 1:(0.05-0.15):(5-10).
[0011] Further, the preparation method of the pretreated titanium dioxide is as follows: titanium dioxide is placed in a hydrogen fluoride solution, soaking for 16-24h, washing, drying and grinding to obtain the pretreated titanium dioxide. In the preparation process of the pretreated titanium dioxide, the mass ratio of titanium dioxide and hydrogen fluoride is 100:(10-20).
[0012] Further, in step S3, the organic acid corrosion inhibitor is one or more of methyl succinic acid, octyl phosphonic acid, adipic acid, succinic acid, citric acid and 2-mercaptobenzimidazole.
[0013] Further, in step S3, the mass ratio of the prepolymer, 1,4-butanediol, polyether modified MQ resin, tert-butyl-p-dihydroxybenzene, modified titanium dioxide, polypropylene oxide triol, and organic acid corrosion inhibitor is 100:(2-4):(45-55):(10-15):(10-20):(1-3):(0.1-0.3).
[0014] Compared with the prior art, the present application has the following advantages: 1. The present application introduces polyether modified MQ resin. The MQ resin is prepared by water capture method with tetramethyl disiloxane as precursor and methyl triethoxysilane as end-capping agent, without adding water and organic solvent, thereby reducing the environmental pollution of waste liquid. The methyl triethoxysilane end-caps the MQ resin, which can enhance the hydrophobicity of the MQ resin, effectively isolate the invasion of water vapor, slow down the electrochemical corrosion of the copper-aluminum pipe welding point in a humid environment, and thus prolong the service life of the welding point. Compared with white carbon black, the inorganic silica core of the MQ resin is rich in methyl on the outer layer, which can significantly improve the thermodynamic properties and hydrophobicity of the protective glue. The MQ resin is modified by hydrosilylation reaction, and the carbon-carbon double bond on the allyl polyoxyethylene methyl ether reacts with the silicon-hydrogen bond on the MQ resin to generate a carbon-silicon bond with high temperature resistance, thereby improving the high temperature stability of the protective glue. At the same time, the glass transition temperature of the polyether segment is low, which helps to improve the low temperature toughness of the protective glue, thereby reducing the deformation of the protective glue under high and low temperature cycles, and avoiding the protective glue from falling off or cracking from the surface of the welding point due to thermal expansion and cold contraction.
[0015] 2. The present application introduces modified titanium dioxide as filler. Hydrogen fluoride pretreatment of titanium dioxide can not only increase the specific surface area and promote the adhesion of the protective glue to the copper-aluminum pipe welding point, but also improve the surface hydroxyl content, which is beneficial to the silane modification of the surface of the titanium dioxide. Grafting hexamethyl disilazane onto the surface of the titanium dioxide improves the hydrophobicity of the titanium dioxide, forms a hydrophobic barrier for the protective glue, slows down the penetration of water vapor and corrosive ions into the welding point, and prevents the welding point from electrochemical corrosion. At the same time, the hexamethyl disilazane grafted on the surface of the titanium dioxide has similar surface energy to polyurethane and MQ resin, and has good compatibility, which avoids the agglomeration of the filler and promotes the uniform dispersion of the filler in the protective glue. In addition, the excellent thermal stability and anti-aging property of titanium dioxide can improve the tensile strength and elongation at break of the polyurethane elastomer, thereby improving the mechanical properties of the protective glue.
[0016] 3. This invention introduces N-hexadecyl diethanolamine as a branch of the polyurethane. The hexadecyl chain on it promotes the formation of micro-phase separation in the polyurethane network, synergistically contributing to low-temperature toughness with the polyether segments; it also further enhances hydrophobicity and improves the waterproofness of the protective adhesive. Simultaneously, this invention introduces tert-butyl-p-diphenol as an antioxidant to prevent polymer oxidative degradation at high temperatures, enhancing the heat aging resistance of the protective adhesive. Organic acids are introduced as corrosion inhibitors. On the one hand, organic acids can remove metal oxides from the solder joint surface, improving the adhesion of the protective adhesive to the solder joint surface; on the other hand, they prevent active substances from oxidizing and corroding the metal materials on the solder joint, thereby improving the antioxidant capacity of the protective adhesive. Polypropylene triol is used as a crosslinking agent to balance toughness and hardness, improving the service life of the protective adhesive. Detailed Implementation
[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] In the following examples, the CAS number of tetramethyldisiloxane is 3277-26-7; the CAS number of methyltriethoxysilane is 2031-67-6; the CAS number of Karstedt catalyst is 68478-92-2; the CAS number of hexamethyldisilazane is 999-97-3; the CAS number of N,N-dimethylformamide is 68-12-2; the CAS number of polypropylene glycol is 25322-69-4; and the CAS number of toluene-2,4-diisocyanate is... The CAS number is 584-84-9; the CAS number for N-hexadecyl diethanolamine is 18924-67-9; the CAS number for tert-butyl-p-diphenol is 1948-33-0; the CAS number for polypropylene triol is [missing information]; the CAS number for 2-mercaptobenzimidazole is 583-39-1; the CAS number for octylphosphonic acid is 4724-48-5; the average molar mass of allyl polyoxyethylene methyl ether is 360 g / mol; the model number for polypropylene triol is N330.
[0019] Example 1: A method for preparing a protective adhesive material to prevent oxidation of copper-aluminum pipe weld joints: S1: 65 parts of glacial acetic acid and 14 parts of tetramethyldisiloxane were added to 0.5 parts of concentrated sulfuric acid and stirred at 30°C for 30 min. Then, 35 parts of methyltriethoxysilane were added and heated at 50°C for 2 h. After cooling to room temperature, sodium bicarbonate was added to adjust the pH to 7. The acidic water layer was removed, and sodium sulfate was added to the organic layer to remove moisture. The mixture was then rotary evaporated and vacuum dried for 2 h to obtain MQ resin. S2: 40 parts of MQ resin and 20 parts of allyl polyoxyethylene methyl ether were added into toluene, stirred uniformly, 0.005 parts of Karstedt catalyst was added, heated at 80°C for 3h, rotary evaporation, washing collection, polyether modified MQ resin was obtained; S3: 100 parts of titanium dioxide was placed in 10 parts of hydrogen fluoride solution, soaked for 16h, washed, dried, ground, and pretreated titanium dioxide was obtained; S4: 10 parts of pretreated titanium dioxide, 0.5 parts of hexamethyl disilazane and 50 parts of N, N-dimethyl formamide were placed in a flask, stirred uniformly, heated at 90°C for 2h, washed, vacuum dried for 4h, and modified titanium dioxide was obtained; S5: 100 parts of polyoxypropylene glycol was mixed with 25 parts of toluene-2, 4-diisocyanate, reacted at 50°C for 30min, 20 parts of N-hexadecyl diethanolamine was added, slowly heated to 75°C for 3h, and a prepolymer was obtained; S6: 100 parts of the prepolymer, 2 parts of 1, 4-butanediol and 45 parts of polyether modified MQ resin were stirred uniformly, 10 parts of tert-butyl-p-dihydroxybenzene, 10 parts of modified titanium dioxide, 1 part of polyoxypropylene triol, 0.05 parts of 2-mercaptobenzimidazole and 0.05 parts of octyl phosphonic acid were added, stirred uniformly, and bubbles were removed under vacuum to obtain a solder joint protection adhesive.
[0020] Example 2: A preparation method of a protective adhesive material for preventing copper-aluminum pipe solder joint oxidation: S1: 70 parts of glacial acetic acid and 16 parts of tetramethyl disiloxane were added into 0.75 parts of concentrated sulfuric acid, stirred at 30°C for 45min, 38 parts of methyl triethoxysilane was added, heated at 55°C for 3h, cooled at room temperature, sodium bicarbonate was added to adjust the pH to 7, the acid water layer was removed, sodium sulfate was added to the organic layer to remove water, rotary evaporation, vacuum drying for 3h, and MQ resin was obtained; S2: 50 parts of MQ resin and 25 parts of allyl polyoxyethylene methyl ether were added into toluene, stirred uniformly, 0.012 parts of Karstedt catalyst was added, heated at 85°C for 4h, rotary evaporation, washing collection, and polyether modified MQ resin was obtained; S3: 100 parts of titanium dioxide was placed in 10 parts of hydrogen fluoride solution, soaked for 16h, washed, dried, ground, and pretreated titanium dioxide was obtained; S4: 10 parts of pretreated titanium dioxide, 0.5 parts of hexamethyl disilazane and 50 parts of N, N-dimethyl formamide were placed in a flask, stirred uniformly, heated at 90°C for 2h, washed, vacuum dried for 4h, and modified titanium dioxide was obtained; S5: 100 parts of polyoxypropylene glycol was mixed with 25 parts of toluene-2, 4-diisocyanate, reacted at 50°C for 30min, 20 parts of N-hexadecyl diethanolamine was added, slowly heated to 75°C for 3h, and a prepolymer was obtained; S6: 100 parts of the prepolymer, 2 parts of 1,4-butanediol and 45 parts of the polyether modified MQ resin were stirred uniformly, then 10 parts of t-butyl-p-dihydroxybenzene, 10 parts of the modified titanium dioxide, 1 part of polyoxypropylene triol, 0.05 parts of 2-mercaptobenzimidazole and 0.05 parts of octyl phosphonic acid were added, stirred uniformly, and the air bubbles were removed under vacuum to obtain the solder joint protection glue.
[0021] Example 3: A preparation method of a protection glue material for preventing copper-aluminum pipe solder joint oxidation: S1: 75 parts of glacial acetic acid and 18 parts of tetramethyl disiloxane were added into 1 part of concentrated sulfuric acid, stirred at 40°C for 60 min, 40 parts of methyl triethoxysilane was added, heated at 60°C for 4h, cooled at room temperature, sodium bicarbonate was added to adjust the pH to 7, the acid water layer was removed, sodium sulfate was added to the organic layer to remove water, rotary evaporation, vacuum drying for 4h, to obtain MQ resin; S2: 60 parts of the MQ resin and 30 parts of allyl polyoxyethylene methyl ether were added into toluene and stirred uniformly, 0.02 parts of Karstedt catalyst was added, heated at 90°C for 5h, rotary evaporation, washing and collection to obtain the polyether modified MQ resin; S3: 100 parts of titanium dioxide was placed in 10 parts of hydrogen fluoride solution, soaked for 16h, washed, dried and ground to obtain the pretreated titanium dioxide; S4: 10 parts of the pretreated titanium dioxide, 0.5 parts of hexamethyl disilazane and 50 parts of N,N-dimethylformamide were placed in a flask, stirred uniformly, heated at 90°C for 2h, washed, vacuum dried for 4h to obtain the modified titanium dioxide; S5: 100 parts of polyoxypropylene glycol was mixed with 25 parts of toluene-2,4-diisocyanate, reacted at 50°C for 30 min, 20 parts of N-n-hexadecyl diethanolamine was added, slowly heated to 75°C for 3h to obtain the prepolymer; S6: 100 parts of the prepolymer, 2 parts of 1,4-butanediol and 45 parts of the polyether modified MQ resin were stirred uniformly, then 10 parts of t-butyl-p-dihydroxybenzene, 10 parts of the modified titanium dioxide, 1 part of polyoxypropylene triol, 0.05 parts of 2-mercaptobenzimidazole and 0.05 parts of octyl phosphonic acid were added, stirred uniformly, and the air bubbles were removed under vacuum to obtain the solder joint protection glue.
[0022] Example 4: A preparation method of a protection glue material for preventing copper-aluminum pipe solder joint oxidation: S1: 75 parts of glacial acetic acid and 18 parts of tetramethyl disiloxane were added into 1 part of concentrated sulfuric acid, stirred at 40°C for 60 min, 40 parts of methyl triethoxysilane was added, heated at 60°C for 4h, cooled at room temperature, sodium bicarbonate was added to adjust the pH to 7, the acid water layer was removed, sodium sulfate was added to the organic layer to remove water, rotary evaporation, vacuum drying for 4h, to obtain MQ resin; S2: 60 parts of MQ resin and 30 parts of allyl polyoxyethylene methyl ether were added into toluene, stirred uniformly, 0.02 parts of Karstedt catalyst was added, heated at 90°C for 5h, rotary evaporation, washing collection, to obtain polyether modified MQ resin; S3: 100 parts of titanium dioxide was placed in 15 parts of hydrogen fluoride solution, soaked for 20h, washed, dried, ground, to obtain pretreated titanium dioxide; S4: 10 parts of pretreated titanium dioxide, 1 part of hexamethyl disilazane and 75 parts of N, N-dimethylformamide were placed in a flask, stirred uniformly, heated at 100°C for 3h, washed, vacuum dried for 5h, to obtain modified titanium dioxide; S5: 100 parts of polyoxypropylene glycol was mixed with 25 parts of toluene-2, 4-diisocyanate, reacted at 50°C for 30min, 20 parts of N-n-hexadecyl diethanolamine was added, slowly heated to 75°C for 3h, to obtain a prepolymer; S6: 100 parts of prepolymer, 2 parts of 1, 4-butanediol and 45 parts of polyether modified MQ resin were stirred uniformly, then 10 parts of tert-butyl p-dihydroxybenzene, 10 parts of modified titanium dioxide, 1 part of polyoxypropylene triol, 0.05 parts of 2-mercaptobenzimidazole, 0.05 parts of octyl phosphonic acid were added, stirred uniformly, removed bubbles under vacuum, to obtain a solder joint protection adhesive.
[0023] Example 5: a method for preparing a protective adhesive material for preventing copper-aluminum pipe solder joint oxidation: S1: 75 parts of glacial acetic acid, 18 parts of tetramethyl disiloxane were added into 1 part of concentrated sulfuric acid, stirred at 40°C for 60min, 40 parts of methyl triethoxysilane was added, heated at 60°C for 4h, cooled at room temperature, sodium bicarbonate was added to adjust the pH to 7, the acid water layer was removed, sodium sulfate was added to the organic layer to remove water, rotary evaporation, vacuum drying for 4h, to obtain MQ resin; S2: 60 parts of MQ resin and 30 parts of allyl polyoxyethylene methyl ether were added into toluene, stirred uniformly, 0.02 parts of Karstedt catalyst was added, heated at 90°C for 5h, rotary evaporation, washing collection, to obtain polyether modified MQ resin; S3: 100 parts of titanium dioxide was placed in 20 parts of hydrogen fluoride solution, soaked for 24h, washed, dried, ground, to obtain pretreated titanium dioxide; S4: 10 parts of pretreated titanium dioxide, 1.5 parts of hexamethyl disilazane and 100 parts of N, N-dimethylformamide were placed in a flask, stirred uniformly, heated at 110°C for 4h, washed, vacuum dried for 6h, to obtain modified titanium dioxide; S5: 100 parts of polyoxypropylene glycol was mixed with 25 parts of toluene-2, 4-diisocyanate, reacted at 50°C for 30min, 20 parts of N-n-hexadecyl diethanolamine was added, slowly heated to 75°C for 3h, to obtain a prepolymer; S6: 100 parts of the prepolymer, 2 parts of 1,4-butanediol and 45 parts of the polyether modified MQ resin were stirred uniformly, then 10 parts of t-butyl-p-dihydroxybenzene, 10 parts of the modified titanium dioxide, 1 part of polyoxypropylene triol, 0.05 parts of 2-mercaptobenzimidazole and 0.05 parts of octyl phosphonic acid were added and stirred uniformly, and bubbles were removed under vacuum to obtain the solder joint protection adhesive.
[0024] Example 6: A preparation method of a protection adhesive material for preventing oxidation of a copper-aluminum pipe solder joint: S1: 75 parts of glacial acetic acid and 18 parts of tetramethyldisiloxane were added to 1 part of concentrated sulfuric acid, stirred at 40°C for 60 min, 40 parts of methyl triethoxysilane were added, heated at 60°C for 4h, cooled at room temperature, sodium bicarbonate was added to adjust the pH to 7, the acid water layer was removed, sodium sulfate was added to the organic layer to remove water, rotary evaporation, vacuum drying for 4h, to obtain an MQ resin; S2: 60 parts of the MQ resin and 30 parts of allyl polyoxyethylene methyl ether were added to toluene and stirred uniformly, 0.02 parts of Karstedt catalyst was added, heated at 90°C for 5h, rotary evaporation, washing and collection to obtain a polyether modified MQ resin; S3: 100 parts of titanium dioxide were placed in 20 parts of hydrogen fluoride solution, soaked for 24h, washed, dried and ground to obtain pretreated titanium dioxide; S4: 10 parts of the pretreated titanium dioxide, 1.5 parts of hexamethyldisilazane and 100 parts of N,N-dimethylformamide were placed in a flask, stirred uniformly, heated at 110°C for 4h, washed, vacuum dried for 6h to obtain modified titanium dioxide; S5: 100 parts of polyoxypropylene glycol was mixed with 30 parts of toluene-2,4-diisocyanate, reacted at 55°C for 45 min, 23 parts of N-n-hexadecyl diethanolamine was added, slowly heated to 80°C for 4h to obtain a prepolymer; S6: 100 parts of the prepolymer, 3 parts of 1,4-butanediol and 50 parts of the polyether modified MQ resin were stirred uniformly, then 12 parts of t-butyl-p-dihydroxybenzene, 15 parts of the modified titanium dioxide, 2 parts of polyoxypropylene triol, 0.1 parts of 2-mercaptobenzimidazole and 0.1 parts of octyl phosphonic acid were added and stirred uniformly, and bubbles were removed under vacuum to obtain the solder joint protection adhesive.
[0025] Example 7: A preparation method of a protection adhesive material for preventing oxidation of a copper-aluminum pipe solder joint: S1: 75 parts of glacial acetic acid and 18 parts of tetramethyldisiloxane were added to 1 part of concentrated sulfuric acid, stirred at 40°C for 60 min, 40 parts of methyl triethoxysilane were added, heated at 60°C for 4h, cooled at room temperature, sodium bicarbonate was added to adjust the pH to 7, the acid water layer was removed, sodium sulfate was added to the organic layer to remove water, rotary evaporation, vacuum drying for 4h, to obtain an MQ resin; S2: 60 parts of MQ resin and 30 parts of allyl polyoxyethylene methyl ether were added into toluene, stirred uniformly, 0.02 parts of Karstedt catalyst was added, heated at 90℃ for 5h, rotary evaporation, washing collection, to obtain polyether modified MQ resin; S3: 100 parts of titanium dioxide was placed in 20 parts of hydrogen fluoride solution, soaked for 24h, washed, dried, ground, to obtain pretreated titanium dioxide; S4: 10 parts of pretreated titanium dioxide, 1.5 parts of hexamethyldisilazane and 100 parts of N,N-dimethylformamide were placed in a flask, stirred uniformly, heated at 110℃ for 4h, washed, vacuum dried for 6h, to obtain modified titanium dioxide; S5: 100 parts of polyoxypropylene glycol was mixed with 35 parts of toluene-2,4-diisocyanate, reacted at 60℃ for 60min, 25 parts of N-n-hexadecyl diethanolamine was added, slowly heated to 85℃ for 5h, to obtain a prepolymer; S6: 100 parts of prepolymer, 4 parts of 1,4-butanediol and 55 parts of polyether modified MQ resin were stirred uniformly, then 15 parts of tert-butyl-p-diphenol, 20 parts of modified titanium dioxide, 3 parts of polyoxypropylene triol, 0.15 parts of 2-mercaptobenzimidazole, 0.15 parts of octyl phosphonic acid were added, stirred uniformly, to remove bubbles under vacuum, to obtain a solder joint protection adhesive.
[0026] Comparative Example 1: A method for preparing a protective adhesive material for preventing oxidation of copper-aluminum pipe solder joints: the MQ resin was not polyether modified, i.e. step S2 was not performed; S6: 100 parts of prepolymer, 4 parts of 1,4-butanediol and 55 parts of MQ resin were stirred uniformly, then 15 parts of tert-butyl-p-diphenol, 20 parts of modified titanium dioxide, 3 parts of polyoxypropylene triol, 0.15 parts of 2-mercaptobenzimidazole, 0.15 parts of octyl phosphonic acid were added, stirred uniformly, to remove bubbles under vacuum, to obtain a solder joint protection adhesive; The remaining steps were the same as in Example 7.
[0027] Comparative Example 2: A method for preparing a protective adhesive material for preventing oxidation of copper-aluminum pipe solder joints: the titanium dioxide was not pretreated with strong acid, i.e. step S3 was not performed; S4: 10 parts of titanium dioxide, 1.5 parts of hexamethyldisilazane and 100 parts of N,N-dimethylformamide were placed in a flask, stirred uniformly, heated at 110℃ for 4h, washed, vacuum dried for 6h, to obtain modified titanium dioxide; The remaining steps were the same as in Example 7.
[0028] Preparation method of a protective adhesive material for preventing oxidation of a copper-aluminum pipe welding point according to Comparative Example 3: S5: 100 parts of polyoxypropylene diol were mixed with 35 parts of toluene-2,4-diisocyanate, and reacted at 60°C for 60 min, and then slowly heated to 85°C for 5 h to obtain a prepolymer; S6: 100 parts of the prepolymer, 4 parts of 1,4-butanediol, and 55 parts of a polyether-modified MQ resin were stirred uniformly, and then 15 parts of t-butyl-p-dihydroxyphenol, 20 parts of modified titanium dioxide, and 3 parts of polyoxypropylene triol were added and stirred uniformly, and then bubbles were removed under vacuum to obtain a welding point protective adhesive; The remaining steps were the same as in Example 7.
[0029] Test: The welding point protective adhesive samples prepared according to the examples and comparative examples were subjected to heat resistance testing according to GB / T 1733-1993, peel strength testing according to GB / T 2790-1995, and salt spray resistance testing according to GB / T 1771-1991.
[0030] Table 1: Related index data of the welding point protective adhesive
[0031] Conclusion: By adjusting the proportions of the components of the welding point protective adhesive, the welding point protective adhesive has excellent anti-oxidation corrosion, adhesion, and thermal stability.
[0032] In Comparative Example 1, the MQ resin was not modified with polyether, which reduced the compatibility of the MQ resin with the polyurethane and was not conducive to the uniform dispersion of the MQ resin in the organic system. In addition, due to the lack of polyether segments, the low-temperature toughness of the protective adhesive was reduced, which increased the brittleness of the welding point protective adhesive in high-low temperature cycles and reduced the adhesion of the protective adhesive to the welding point.
[0033] In Comparative Example 2, the titanium dioxide was not pretreated with strong acid. On the one hand, this reduced the content of hydroxyl groups on the surface of the titanium dioxide, which reduced the grafting of hexamethyldisilazane on the surface of the titanium dioxide, reduced the hydrophobicity of the filler, increased the risk of water vapor attacking the welding point, and was not conducive to the protective adhesive playing a role in preventing oxidation of the welding point. On the other hand, the specific surface area of the titanium dioxide was reduced, which reduced the adhesion of the protective adhesive to the copper-aluminum pipe welding point.
[0034] In Comparative Example 3, no hexadecyl branched chain was introduced as a polyurethane branched chain, which reduced the mechanical properties of the polyurethane elastomer, thereby reducing the dynamic mechanical properties of the protective adhesive. In addition, no organic acid was added to the protective adhesive, which not only reduced the adhesion of the protective adhesive to the welding point, but also increased the risk of oxidation corrosion of the active substances to the welding point.
[0035] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims
1. A method for preparing a protective adhesive material to prevent oxidation of copper-aluminum pipe weld joints, characterized in that: The method comprises the following steps: S1: adding MQ resin and allyl polyoxyethylene methyl ether into toluene, stirring uniformly, adding platinum catalyst, heating at 80-90 DEG C for 3-5h, rotary evaporation, washing and collecting to obtain polyether modified MQ resin; S2: mixing polyoxypropylene diol with toluene-2, 4-diisocyanate, heating at 50-60 DEG C for 30-60min, adding N-n-hexadecyl diethanolamine, heating to 75-85 DEG C for 3-5h to obtain prepolymer; S3: stirring the prepolymer, 1, 4-butanediol and polyether modified MQ resin uniformly, then adding tert-butyl p-diphenol, modified titanium dioxide, polyoxypropylene triol and organic acid corrosion inhibitor, stirring uniformly, removing air bubbles under vacuum to obtain solder joint protection adhesive.
2. The method for preparing the protective adhesive material for preventing oxidation of the copper-aluminum pipe welding point according to claim 1, characterized in that: In step S1, the platinum catalyst is Karstedt catalyst; the mass ratio of MQ resin, allyl polyoxyethylene methyl ether and platinum catalyst is (40-60):(20-30):(0.005-0.02).
3. The method for preparing the protective adhesive material for preventing oxidation of the copper-aluminum pipe welding point according to claim 1, characterized in that: In step S1, the preparation method of the MQ resin is as follows: adding glacial acetic acid and tetramethyldisiloxane into concentrated sulfuric acid, stirring at 30-40 DEG C for 30-60min, adding methyl triethoxysilane, heating at 50-60 DEG C for 2-4h, cooling at room temperature, adding sodium bicarbonate to adjust pH to 7, removing acid water layer, adding sodium sulfate to the organic layer to remove water, rotary evaporation, vacuum drying for 2-4h to obtain MQ resin.
4. The method for preparing the protective adhesive material for preventing oxidation of the copper-aluminum tube welding point according to claim 3, characterized in that: In the preparation process of the MQ resin, the mass ratio of glacial acetic acid, tetramethyldisiloxane, concentrated sulfuric acid and methyl triethoxysilane is (65-75):(14-18):(0.5-1):(35-40).
5. The method for preparing the protective adhesive material for preventing oxidation of the copper-aluminum tube welding point according to claim 1, characterized in that: In step S2, the mass ratio of polyoxypropylene diol, toluene-2, 4-diisocyanate and N-n-hexadecyl diethanolamine is 100:(25-35):(20-25).
6. The method for preparing the protective adhesive material for preventing oxidation of the copper-aluminum pipe welding point according to claim 1, characterized in that: In step S3, the preparation method of the modified titanium dioxide is as follows: placing pretreated titanium dioxide, hexamethyldisilazane and N, N-dimethylformamide in a flask, stirring uniformly, heating at 90-110 DEG C for 2-4h, washing, vacuum drying for 4-6h to obtain modified titanium dioxide; In the preparation process of the modified titanium dioxide, the mass ratio of pretreated titanium dioxide, hexamethyldisilazane and N, N-dimethylformamide is 1:(0.05-0.15):(5-10).
7. The method for preparing a protective adhesive material for preventing oxidation of copper-aluminum pipe weld joints according to claim 6, characterized in that: The preparation method of the pretreated titanium dioxide is as follows: placing titanium dioxide in hydrogen fluoride solution, soaking for 16-24h, washing, drying and grinding to obtain pretreated titanium dioxide; In the preparation process of the pretreated titanium dioxide, the mass ratio of titanium dioxide and hydrogen fluoride is 100:(10-20).
8. The method of claim 1, wherein the method comprises: 5 mixing the copper-aluminum pipe solder joint protection adhesive material with a solvent to form a mixture; and drying the mixture to form the copper-aluminum pipe solder joint protection adhesive material. In step S3, the organic acid corrosion inhibitor is one or more of methyl butanedioic acid, octyl phosphonic acid, adipic acid, butanedioic acid, citric acid and 2-mercaptobenzimidazole.
9. The method for preparing a protective adhesive material for preventing oxidation of copper-aluminum pipe weld joints according to claim 1, characterized in that: The mass ratio of the prepolymer, 1,4-butanediol, polyether modified MQ resin, tert-butyl-p-diphenol, modified titanium dioxide, polypropylene oxide triol, and organic acid corrosion inhibitor in step S3 is 100:(2-4):(45-55):(10-15):(10-20):(1-3):(0.1-0.3).
10. The protective glue material prepared by the method of any one of claims 1-9.