Salt fog resistant additive and method of making same

Abstract

The present application relates to a kind of salt fog resistant additives and its preparation method, belong to anticorrosive coating additive technical field, the key points of technical scheme are that the salt fog resistant additive, by the powder of 5-15 microns particle size is composed, the powder includes elastomer microparticle 60-80 parts, inorganic filler 20-30 parts, para alkyl-substituted phenolic resin 5-10 parts, resin modifier 3-5 parts, lignin sodium sulfate 5-10 parts, zinc oxide 3-5 parts, double dipentyl 1-2 parts, coupling agent 1-2 parts by mass fraction;The elastomer microparticle is the three-dimensional network structure formed by C5H8, C8H8, C4H6 monomer crosslinking;The present application is added to existing anticorrosive coating system, can effectively improve the salt fog resistance of forming paint film and impact resistance.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating additives, and in particular to a salt spray resistant additive and its preparation method. Background Technology

[0002] Devices or equipment used outdoors for extended periods are subject to high and low temperatures, ultraviolet radiation, and electrochemical damage. The surface coatings of their metal parts require excellent corrosion resistance, especially in saline environments such as seawater, high-temperature / high-humidity environments, or outdoor metal substrate facilities, where the salt spray resistance of the coatings is even more critical.

[0003] Salt spray corrosion refers to the corrosion phenomenon that occurs on the surface of materials in a humid environment containing salt, caused by the action of salt. This phenomenon is particularly common in marine environments or coastal areas because the air in these areas usually contains a high concentration of salt. Salt spray corrosion can damage a variety of materials, including metals, plastics, rubber, and coatings, affecting their performance and service life. The salt spray corrosion process typically includes the following steps: 1) Salt deposition: Under high humidity or rainfall conditions, salt in the air (such as sodium chloride) will be deposited on the material surface. 2) Electrochemical corrosion: Salt forms an electrolyte solution on the material surface, promoting electrochemical reactions on the metal surface, leading to metal corrosion. 3) Penetration and diffusion: Salt can penetrate into the pores or cracks of the material, further diffusing into the interior of the material, intensifying corrosion. 4) Formation of corrosion products: As the corrosion process proceeds, corrosion products such as rust and oxides will form on the material surface. 5) Degradation of material properties: Corrosion will lead to a decrease in the strength, toughness, conductivity, and other properties of the material, and may even lead to structural failure.

[0004] Existing anti-corrosion coatings primarily rely on resin as a base material, with rust-inhibiting inorganic fillers enhancing their anti-corrosion capabilities. The amount of these fillers directly impacts the coating's anti-corrosion performance. However, the addition of rust-inhibiting inorganic fillers can easily create voids on the coating surface. In high-salt-spray environments, these voids can lead to electrochemical corrosion of the metal surface due to potential differences. Furthermore, the addition of rust-inhibiting inorganic fillers can make the coating film brittle. Consequently, when metal parts are subjected to external impact forces, the coating near the stress point is prone to breakage and peeling, resulting in localized exposure of the metal parts and compromising surface protection. Summary of the Invention

[0005] One objective of this invention is to provide a salt spray resistant additive that, when added to existing anti-corrosion coating systems, can effectively improve the salt spray resistance and impact resistance of the formed coating film.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a salt spray resistant additive, composed of powder with a particle size of 5-15 micrometers, wherein the powder, by mass parts, includes 60-80 parts of elastomer microparticles, 20-30 parts of inorganic filler, 5-10 parts of para-alkyl-substituted phenolic resin, 3-5 parts of resin modifier, 5-10 parts of sodium lignin sulfate, 3-5 parts of zinc oxide, 1-2 parts of diammonium phosphate, and 1-2 parts of coupling agent;

[0007] The elastomer microparticles are a three-dimensional network structure formed by cross-linking of C5H8, C8H8, and C4H6 monomers;

[0008] The resin modifier is prepared by the following method:

[0009] Polydimethylsiloxane was added to ethanol to prepare a polydimethylsiloxane solution with a concentration of 2-5 wt%.

[0010] Bisphenol A epoxy resin is heated to 40-50°C and then added dropwise to a polydimethylsiloxane solution. During the addition process, mechanical stirring is performed to ensure that the polydimethylsiloxane and bisphenol A epoxy resin are fully mixed. Dibutyltin dilaurate is added and stirred evenly. The mixed solution is then placed in a temperature environment of 110-130°C to allow for a complete reaction, and the ethanol in the mixed solution is allowed to evaporate to obtain the resin modifier.

[0011] The mass ratio of bisphenol A epoxy resin, polydimethylsiloxane, and dibutyltin dilaurate is 100:80-85:1-2.

[0012] Through the above technical solution, when the salt spray resistant additive is added to the anti-corrosion coating system, because it is composed of tiny powder particles of 5-15 micrometers and contains coupling agents, the powder can be uniformly and well dispersed throughout the entire coating system.

[0013] The salt spray resistant additive powder uses elastomer microparticles as the main material. These elastomer microparticles are a three-dimensional network structure formed by the cross-linking of C5H8, C8H8, and C4H6 monomers. When subjected to external force, these elastomer microparticles deform and return to their original shape after the force is removed, exhibiting good elasticity. This results in the salt spray resistant additive powder possessing excellent elasticity and flexibility. When the coating is formed, the salt spray resistant additive powder dissolved and dispersed in the resin system forms a dense and continuous film structure on the coating surface, effectively isolating the external salt spray environment from the main equipment structure. Furthermore, because the salt spray resistant additive enhances the elasticity and flexibility of the coating... The coating's properties enable it to better resist stress damage under salt spray conditions, and the coating is less prone to localized peeling. Due to its special three-dimensional network structure and extremely small particle size (smaller than salt spray resistant additive powder), the elastomer microparticles can be well distributed in the coating structure. When the coating is locally damaged by external forces, the network structure of the elastomer microparticles can spontaneously or under external stimulation through internal reversible covalent bonds and supramolecular forces. The mobility of polymer chain segments can allow the polymer to migrate and cross the wound, thus closing the wound. Subsequently, the material's properties are restored through the reconstruction of reversible covalent bonds or supramolecular interactions.

[0014] Zinc oxide in the salt spray resistant additive has the ability to absorb ultraviolet rays, effectively resisting aging caused by ultraviolet rays. This improves the coating's anti-aging ability during outdoor use, allowing it to maintain its salt spray resistance. Furthermore, zinc oxide reacts with corrosive media such as water and oxygen to form a dense zinc oxide layer, which slows down further penetration and improves the coating's chemical corrosion resistance. Sodium lignin sulfate in the salt spray resistant additive is a versatile natural polymer compound. It not only acts as an aggregate to improve the wear resistance of the molded paint film, but also possesses many active functional groups, such as hydroxyl, carboxyl, and sulfonic acid groups. These functional groups allow sodium lignin sulfate to form coordination bonds with metal ions, thereby significantly improving the adhesion between the paint film and the metal. This results in a tighter adhesion of the paint film to the metal surface, preventing it from peeling off and thus providing a superior salt spray resistance.

[0015] In summary, anti-corrosion coatings with added salt spray resistant additives exhibit stronger adhesion to metals after forming a film, and the film possesses better toughness. Therefore, it is less prone to peeling due to localized stress damage when subjected to external impacts. Furthermore, minor damage to the film caused by external forces can be repaired through the material's self-healing function, resulting in a more durable film that consistently maintains excellent salt spray resistance. Most substances in the salt spray resistant additives possess good chemical stability, enabling them to resist salt spray corrosion. The synergistic effect of various formulation components in the salt spray resistant agent, or their combination with metal ions, forms a dense film structure with multiple layers and different structures, effectively shielding and isolating the metal substrate, cutting off the metal's electrochemical corrosion path, and thus ensuring the salt spray resistance of the coating film.

[0016] Preferably, the inorganic filler includes mica powder, silica, and any one or more of nano-calcium carbonate, nano-montmorillonite, and nano-kaolin.

[0017] Through the above technical solutions, mica powder, with its unique lamellar structure, can form a barrier within the material, effectively preventing the penetration of corrosive media such as salt spray. This lamellar structure of mica powder, arranged horizontally in the coating, can block ultraviolet radiation and prevent moisture penetration, thereby improving the weather resistance and salt spray resistance of the coating film. Silica, due to its special three-dimensional network structure, can increase the hardness of the coating film within a certain range and improve the surface smoothness, thus enhancing the coating's washability and alkali corrosion resistance. Silica has extremely strong ultraviolet absorption and infrared reflection characteristics, achieving an absorption rate of over 70% for ultraviolet light within 400nm and a reflectivity of over 70% for infrared light within 400nm. This characteristic helps the coating form a shielding effect, achieving resistance to ultraviolet aging and thermal aging, thus making the coating material more durable and achieving better salt spray corrosion resistance.

[0018] Preferably, the particle size of the mica powder is 1-5 micrometers.

[0019] Preferably, the coupling agent is a silane coupling agent.

[0020] Through the above technical solution, the silane coupling agent reacts chemically with the hydroxyl groups on the surface of silica through the active groups in its molecular structure, changing silica from hydrophilic to hydrophobic, thereby increasing its compatibility with elastomer particles. This modification effectively improves the dispersibility of silica. The silane coupling agent also reacts chemically with the silanol groups on the surface of silica, reducing the affinity between silica particles and decreasing the agglomeration of silica. This modification makes the dispersion of silica in the powder more uniform and reduces the formation of silica networks. As a result, when applied in anti-corrosion coatings, the surface of the formed paint film is denser, thus achieving a better isolation effect and effectively improving the salt spray resistance of the coating.

[0021] Preferably, the reaction time of the mixed solution at a temperature of 110-130°C is 1-2 hours.

[0022] Another object of the present invention is to provide a method for preparing a salt spray resistant additive for use in the manufacture of the aforementioned salt spray resistant additive.

[0023] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0024] A method for preparing a salt spray resistant additive includes the following steps:

[0025] Step S1: Take natural rubber, styrene-butadiene rubber and cis-butadiene rubber and mix them in a mass ratio of 4:2:1. Add para-alkyl-substituted phenolic resin, resin modifier and 1 / 2 inorganic filler and knead at 120-140℃ for 5-30 minutes to obtain mixture A.

[0026] Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier.

[0027] Step S3: Mix mixture A and the modifier at 160-180℃ for 5-15 minutes to obtain mixture B;

[0028] Step S4: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0029] Step S5: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0030] Through the above technical solution, natural rubber, styrene-butadiene rubber, and butadiene rubber are compounded at 120-140℃. The hydroxymethyl groups in the phenolic resin molecules undergo a condensation reaction with the hydroxymethyl groups in the rubber or other phenolic resin molecules to form a cross-linking network, thus completing the initial cross-linking. The resin modifier is a bisphenol A epoxy resin modified with polydimethylsiloxane, which has good hydrophobicity, toughness, resistance to damp heat, thermal stability, and surface properties. When used in conjunction with the phenolic resin, the resin modifier acts as an adhesive, enabling the inorganic fillers to mix better with natural rubber, styrene-butadiene rubber, and butadiene rubber, thereby forming skeletal nodes in the cross-linked macromolecular structure. The remaining inorganic fillers are mixed with zinc oxide, sodium lignin sulfate, diammonium phosphate, and a coupling agent, and then stirred in a sealed environment at 33-40℃. This allows for thorough mixing of various materials, enabling better participation in the secondary mixing chemical reaction. At 160-180℃, mixture A undergoes secondary mixing. Under the synergistic effect of sodium lignin sulfate, diammonium phosphate decomposes upon heating to generate free radicals, triggering a free radical-type cross-linking reaction in the rubber molecular chains, thus resulting in more complete cross-linking of the rubber molecules. Then, mixture B is extruded and granulated to obtain primary raw materials with a particle size no greater than 1 cm. These primary raw materials are then pulverized into primary powder with a particle size of 20-50 mesh. Furthermore, the primary powder is ground at -80℃ to -196℃ to produce powder with a particle size of 5-15 micrometers, thereby breaking down the large-molecule rubber network and generating uniform and stable salt spray resistant powder units containing three-dimensional network structure elastomer particles formed by the cross-linking of C5H8, C8H8, and C4H6 monomers.

[0031] Preferably, in step S1, before mixing natural rubber, styrene-butadiene rubber, and cis-butadiene rubber, the natural rubber is pretreated, the pretreatment including:

[0032] (1) Drying: Place the natural rubber in an environment of 50°C to 60°C to dry it;

[0033] (2) Cut into pieces: Cut the dried natural rubber into small pieces with a diameter of no more than 10 cm.

[0034] (3) Plasticizing: Adjust the roller gap of the open mill, add the cut natural rubber into the open mill, and extrude the natural rubber into uniform thin sheets.

[0035] Through the above technical solution, before mixing natural rubber with styrene-butadiene rubber and butadiene rubber, the natural rubber is first plasticized through pretreatment, which can effectively improve the fluidity of the natural rubber, and thus allow the natural rubber to be mixed more evenly and fully with other materials during subsequent mixing. Attached Figure Description

[0036] The accompanying drawings, which form part of this specification, illustrate embodiments of the invention and, together with the specification, serve to explain the principles of the invention.

[0037] Figure 1 These are images of the salt spray resistance test samples from Experiment Examples 1-3.

[0038] Figure 2 These are images of salt spray resistance test samples from Experiment 4-6.

[0039] Figure 3 These are images of salt spray resistance test samples from Experiment 7-9.

[0040] Figure 4 These are images of salt spray resistance test samples from Experiment Examples 10-12.

[0041] Figure 5 These are images of salt spray resistance test samples from Experimental Examples 13-14 and the control example. Detailed Implementation

[0042] Preparation Example 1

[0043] A resin modifier is prepared by the following method:

[0044] Polydimethylsiloxane was added to ethanol to prepare a polydimethylsiloxane solution with a concentration of 2 wt%.

[0045] Bisphenol A epoxy resin was heated to 40°C and then added dropwise to a polydimethylsiloxane solution. During the addition process, mechanical stirring was performed to ensure that the polydimethylsiloxane and bisphenol A epoxy resin were fully mixed. Dibutyltin dilaurate was added and stirred evenly. The mixed solution was then placed at 110°C for 2 hours to allow the ethanol in the mixed solution to evaporate and escape, thereby obtaining the resin modifier.

[0046] The mass ratio of bisphenol A epoxy resin, polydimethylsiloxane, and dibutyltin dilaurate is 100:80:1.

[0047] Preparation Example 2

[0048] A resin modifier is prepared by the following method:

[0049] Polydimethylsiloxane was added to ethanol to prepare a polydimethylsiloxane solution with a concentration of 2 wt%.

[0050] Bisphenol A epoxy resin was heated to 50°C and then added dropwise to a polydimethylsiloxane solution. During the addition process, mechanical stirring was performed to ensure that the polydimethylsiloxane and bisphenol A epoxy resin were fully mixed. Dibutyltin dilaurate was added and stirred evenly. The mixed solution was then placed at 110°C for 2 hours to allow the ethanol in the mixed solution to evaporate and escape, thereby obtaining the resin modifier.

[0051] The mass ratio of bisphenol A epoxy resin, polydimethylsiloxane, and dibutyltin dilaurate is 100:80:1.

[0052] Preparation Example 3

[0053] A resin modifier is prepared by the following method:

[0054] Polydimethylsiloxane was added to ethanol to prepare a polydimethylsiloxane solution with a concentration of 2 wt%.

[0055] Bisphenol A epoxy resin was heated to 40°C and then added dropwise to a polydimethylsiloxane solution. During the addition process, mechanical stirring was performed to ensure that the polydimethylsiloxane and bisphenol A epoxy resin were fully mixed. Dibutyltin dilaurate was added and stirred evenly. The mixed solution was then placed at 110°C for 2 hours to allow the ethanol in the mixed solution to evaporate and escape, thereby obtaining the resin modifier.

[0056] The mass ratio of bisphenol A epoxy resin, polydimethylsiloxane, and dibutyltin dilaurate is 100:85:2.

[0057] Preparation Example 4

[0058] A resin modifier is prepared by the following method:

[0059] Polydimethylsiloxane was added to ethanol to prepare a polydimethylsiloxane solution with a concentration of 5 wt%.

[0060] Bisphenol A epoxy resin was heated to 40°C and then added dropwise to a polydimethylsiloxane solution. During the addition process, mechanical stirring was performed to ensure that the polydimethylsiloxane and bisphenol A epoxy resin were fully mixed. Dibutyltin dilaurate was added and stirred evenly. The mixed solution was then placed at 110°C for 2 hours to allow the ethanol in the mixed solution to evaporate and escape, thereby obtaining the resin modifier.

[0061] The mass ratio of bisphenol A epoxy resin, polydimethylsiloxane, and dibutyltin dilaurate is 100:80:1.

[0062] Preparation Example 5

[0063] A resin modifier is prepared by the following method:

[0064] Polydimethylsiloxane was added to ethanol to prepare a polydimethylsiloxane solution with a concentration of 2 wt%.

[0065] Bisphenol A epoxy resin was heated to 40°C and then added dropwise to a polydimethylsiloxane solution. During the addition process, mechanical stirring was performed to ensure that the polydimethylsiloxane and bisphenol A epoxy resin were fully mixed. Dibutyltin dilaurate was added and stirred evenly. The mixed solution was then placed at 130°C for 2 hours to allow the ethanol in the mixed solution to evaporate and escape, thereby obtaining the resin modifier.

[0066] The mass ratio of bisphenol A epoxy resin, polydimethylsiloxane, and dibutyltin dilaurate is 100:80:1.

[0067] Example

[0068] Example 1

[0069] A method for preparing a salt spray resistant additive includes the following steps:

[0070] Step S1, weigh the following components:

[0071] A total of 70 parts of natural rubber, styrene-butadiene rubber, and butadiene rubber, including 40 parts of natural rubber, 20 parts of styrene-butadiene rubber, and 10 parts of butadiene rubber;

[0072] 20 parts of inorganic filler, including 10 parts of mica powder, 5 parts of silica, and 5 parts of nano-calcium carbonate;

[0073] Five parts of para-alkyl-substituted phenolic resin, five parts of sodium lignin sulfate, three parts of zinc oxide, one part of dipentadiene, and one part of silane coupling agent.

[0074] Three parts of resin modifier were used, and the resin modifier prepared in Preparation Example 1 was used.

[0075] Natural rubber, styrene-butadiene rubber, and cis-butadiene rubber are mixed together, and para-alkyl-substituted phenolic resin, resin modifier, and 1 / 2 inorganic filler are added. The mixture is then kneaded at 120-140℃ for 5-30 minutes to obtain mixture A.

[0076] Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and silane coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier.

[0077] Step S3: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0078] Step S4: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0079] Examples 2-5

[0080] Examples 2-5 have the same process conditions as Example 1, the only difference being that the resin modifier used is the resin modifier prepared in Examples 2-5.

[0081] Example 6

[0082] A method for preparing a salt spray resistant additive includes the following steps:

[0083] Step S1, weigh the following components:

[0084] A total of 70 parts of natural rubber, styrene-butadiene rubber, and butadiene rubber, including 40 parts of natural rubber, 20 parts of styrene-butadiene rubber, and 10 parts of butadiene rubber;

[0085] 20 parts of inorganic filler, including 10 parts of mica powder, 5 parts of silica, and 5 parts of nano-montmorillonite;

[0086] Five parts of para-alkyl-substituted phenolic resin, five parts of sodium lignin sulfate, three parts of zinc oxide, one part of dipentadiene, and one part of silane coupling agent.

[0087] Three parts of resin modifier were used, and the resin modifier prepared in Preparation Example 1 was used.

[0088] Natural rubber, styrene-butadiene rubber, and cis-butadiene rubber are mixed together, and para-alkyl-substituted phenolic resin, resin modifier, and 1 / 2 inorganic filler are added. The mixture is then kneaded at 120-140℃ for 5-30 minutes to obtain mixture A.

[0089] Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and silane coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier.

[0090] Step S3: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0091] Step S4: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0092] Example 7

[0093] A method for preparing a salt spray resistant additive includes the following steps:

[0094] Step S1, weigh the following components:

[0095] A total of 70 parts of natural rubber, styrene-butadiene rubber, and butadiene rubber, including 40 parts of natural rubber, 20 parts of styrene-butadiene rubber, and 10 parts of butadiene rubber;

[0096] 20 parts of inorganic filler, including 10 parts of mica powder, 5 parts of silica, and 5 parts of nano-kaolin;

[0097] Five parts of para-alkyl-substituted phenolic resin, five parts of sodium lignin sulfate, three parts of zinc oxide, one part of dipentadiene, and one part of silane coupling agent.

[0098] Three parts of resin modifier were used, and the resin modifier prepared in Preparation Example 1 was used.

[0099] Natural rubber, styrene-butadiene rubber, and cis-butadiene rubber are mixed together, and para-alkyl-substituted phenolic resin, resin modifier, and 1 / 2 inorganic filler are added. The mixture is then kneaded at 120-140℃ for 5-30 minutes to obtain mixture A.

[0100] Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and silane coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier.

[0101] Step S3: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0102] Step S4: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0103] Example 8

[0104] A method for preparing a salt spray resistant additive includes the following steps:

[0105] Step S1, weigh the following components:

[0106] A total of 70 parts of natural rubber, styrene-butadiene rubber, and butadiene rubber, including 40 parts of natural rubber, 20 parts of styrene-butadiene rubber, and 10 parts of butadiene rubber;

[0107] 30 parts of inorganic filler, including 10 parts of mica powder, 10 parts of silica, and 10 parts of nano-calcium carbonate;

[0108] 10 parts of para-alkyl-substituted phenolic resin, 10 parts of sodium lignin sulfate, 5 parts of zinc oxide, 2 parts of dipentaerythritol, and 2 parts of silane coupling agent.

[0109] Five parts of resin modifier were used, and the resin modifier prepared in Preparation Example 1 was used.

[0110] Natural rubber, styrene-butadiene rubber, and cis-butadiene rubber are mixed together, and para-alkyl-substituted phenolic resin, resin modifier, and 1 / 2 inorganic filler are added. The mixture is then kneaded at 120-140℃ for 5-30 minutes to obtain mixture A.

[0111] Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and silane coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier.

[0112] Step S3: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0113] Step S4: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0114] Comparative Example 1

[0115] A method for preparing a salt spray resistant additive includes the following steps:

[0116] Step S1, weigh the following components:

[0117] A total of 35 parts of natural rubber, styrene-butadiene rubber, and butadiene rubber were contained, including 20 parts of natural rubber, 10 parts of styrene-butadiene rubber, and 5 parts of butadiene rubber.

[0118] 30 parts of inorganic filler, including 10 parts of mica powder, 10 parts of silica, and 10 parts of nano-calcium carbonate;

[0119] 10 parts of para-alkyl-substituted phenolic resin, 10 parts of sodium lignin sulfate, 5 parts of zinc oxide, 2 parts of dipentaerythritol, and 2 parts of silane coupling agent.

[0120] Five parts of resin modifier were used, and the resin modifier prepared in Preparation Example 1 was used.

[0121] Natural rubber, styrene-butadiene rubber, and cis-butadiene rubber are mixed together, and para-alkyl-substituted phenolic resin, resin modifier, and 1 / 2 inorganic filler are added. The mixture is then kneaded at 120-140℃ for 5-30 minutes to obtain mixture A.

[0122] Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and silane coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier.

[0123] Step S3: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0124] Step S4: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0125] Comparative Example 2

[0126] A method for preparing a salt spray resistant additive includes the following steps:

[0127] Step S1, weigh the following components:

[0128] A total of 70 parts of natural rubber, styrene-butadiene rubber, and butadiene rubber, including 40 parts of natural rubber, 20 parts of styrene-butadiene rubber, and 10 parts of butadiene rubber;

[0129] 30 parts of inorganic filler, including 10 parts of mica powder, 10 parts of silica, and 10 parts of nano-calcium carbonate;

[0130] 10 parts of para-alkyl-substituted phenolic resin, 10 parts of sodium lignin sulfate, 5 parts of zinc oxide, 2 parts of dipentadiene, and 2 parts of silane coupling agent.

[0131] Natural rubber, styrene-butadiene rubber, and cis-butadiene rubber are mixed together, and para-alkyl-substituted phenolic resin and 1 / 2 inorganic filler are added. The mixture is then kneaded at 120-140℃ for 5-30 minutes to obtain mixture A.

[0132] Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and silane coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier.

[0133] Step S3: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0134] Step S4: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0135] Comparative Example 3

[0136] A method for preparing a salt spray resistant additive includes the following steps:

[0137] Step S1, weigh the following components:

[0138] A total of 70 parts of natural rubber, styrene-butadiene rubber, and butadiene rubber, including 40 parts of natural rubber, 20 parts of styrene-butadiene rubber, and 10 parts of butadiene rubber;

[0139] 30 parts of inorganic filler, including 10 parts of mica powder, 10 parts of silica, and 10 parts of nano-calcium carbonate;

[0140] 10 parts epoxy resin, 10 parts sodium lignin sulfate, 5 parts zinc oxide, 2 parts diammonium phosphate, 2 parts silane coupling agent.

[0141] Five parts of resin modifier were used, and the resin modifier prepared in Preparation Example 1 was used.

[0142] Natural rubber, styrene-butadiene rubber, and cis-butadiene rubber are mixed together, and para-alkyl-substituted phenolic resin, resin modifier, and 1 / 2 inorganic filler are added. The mixture is then kneaded at 120-140℃ for 5-30 minutes to obtain mixture A.

[0143] Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and silane coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier.

[0144] Step S3: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0145] Step S4: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0146] Comparative Example 4

[0147] A method for preparing a salt spray resistant additive includes the following steps:

[0148] Step S1, weigh the following components:

[0149] A total of 70 parts of natural rubber, styrene-butadiene rubber, and butadiene rubber, including 40 parts of natural rubber, 20 parts of styrene-butadiene rubber, and 10 parts of butadiene rubber;

[0150] 30 parts of inorganic filler, including 10 parts of mica powder, 10 parts of silica, and 10 parts of nano-calcium carbonate;

[0151] 10 parts of para-alkyl-substituted phenolic resin, 10 parts of sodium lignin sulfate, 5 parts of zinc oxide, 2 parts of dipentaerythritol, and 2 parts of silane coupling agent.

[0152] Five parts of resin modifier were used, and the resin modifier prepared in Preparation Example 1 was used.

[0153] Mix the above raw materials and knead them at 120-140℃ for 5-30 minutes to obtain mixture C;

[0154] Step S2: Extrude and granulate the mixture C to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh.

[0155] Step S3: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

[0156] Experimental Project

[0157] Comparison Example

[0158] An anti-corrosion coating comprises 100 parts of epoxy resin, 30 parts of curing agent, 40 parts of anti-corrosion filler, and 20 parts of diluent; wherein the curing agent is polyamide resin and the anti-corrosion filler is talc powder.

[0159] Based on the above formulation as the base coating formulation, the anti-corrosion coatings in the above formulation were replaced proportionally with the salt spray resistant agents prepared in Examples 1-8 and Comparative Examples 1-4, respectively, to obtain Experimental Examples 1-14.

[0160] Experimental Example 1

[0161] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (Example 1), and 20 parts diluent.

[0162] Experimental Example 2

[0163] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (Example 2), and 20 parts diluent.

[0164] Experimental Example 3

[0165] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (Example 3), and 20 parts diluent.

[0166] Experiment Example 4

[0167] An anti-corrosion coating comprises 100 parts of epoxy resin, 30 parts of curing agent, 30 parts of anti-corrosion filler, 10 parts of salt spray resistant additive (Example 4), and 20 parts of diluent.

[0168] Experimental Example 5

[0169] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (Example 5), and 20 parts diluent.

[0170] Experimental Example 6

[0171] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (Example 6), and 20 parts diluent.

[0172] Experimental Example 7

[0173] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (Example 7), and 20 parts diluent.

[0174] Experimental Example 8

[0175] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (Example 8), and 20 parts diluent.

[0176] Experimental Example 9

[0177] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 25 parts anti-corrosion filler, 15 parts salt spray resistant additive (Example 1), and 20 parts diluent.

[0178] Experimental Example 10

[0179] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 20 parts anti-corrosion filler, 20 parts salt spray resistant additive (Example 1), and 20 parts diluent.

[0180] Experimental Example 11

[0181] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (comparative example 1), and 20 parts diluent.

[0182] Experimental Example 12

[0183] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (comparative example 2), and 20 parts diluent.

[0184] Experimental Example 13

[0185] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (comparative example 3), and 20 parts diluent.

[0186] Experimental Example 14

[0187] An anti-corrosion coating comprises 100 parts epoxy resin, 30 parts curing agent, 30 parts anti-corrosion filler, 10 parts salt spray resistant additive (comparative example 4), and 20 parts diluent.

[0188] The anti-corrosion coatings prepared in Experimental Examples 1-14 were sprayed onto iron sheets measuring 0.1cm x 0.1cm x 0.1cm. Before spraying, the surface was cleaned with acetone. The coating thickness was 100μm ± 5μm. The coating was cured at 25 ± 2℃. Then, the following performance tests were performed on the samples from Experimental Examples 1-14.

[0189] The adhesion test was conducted in accordance with GB / T 5210-2006 "Paints and Varnishes - Pull-off Adhesion Test".

[0190] Salt spray resistance test shall be conducted in accordance with GB / T 1771-2007 "Determination of resistance to neutral salt spray of paints and varnishes";

[0191] Impact strength testing shall be conducted in accordance with GB / T 1732-2020, "Test Method for Impact Resistance of Coating Films".

[0192] Artificial aging resistance test shall be conducted in accordance with GB / T 9276-1996 "Test Method for Natural Climate Exposure of Coatings";

[0193] The abrasion resistance test was conducted in accordance with GB / T 1768-2006 "Determination of abrasion resistance of paints and varnishes - Rotary rubber grinding wheel method".

[0194] The test results are shown in the table below.

[0195]

[0196] Table 1 Performance test results of experimental examples

[0197] Figure 1-5 Images of samples from salt spray resistance tests, among which... Figure 1 In the image, numbers 1-3 represent sample images from experimental examples 1-3, respectively. Figure 2 In the image, numbers 4-6 represent sample images from experimental examples 4-6. Figure 3 In the image, numbers 7-9 represent sample images from experimental examples 7-9. Figure 4 In the image, numbers 10-12 represent sample images from experimental examples 10-12. Figure 5 In the image, numbers 13-15 are sample images of experimental examples 13-14 and control examples, respectively.

[0198] As shown in Table 1, replacing some of the anti-corrosion fillers with salt spray resistant additives in conventional anti-corrosion coating formulations can significantly improve the salt spray resistance and impact strength of the formed coating film. It also enhances the film's adhesion, abrasion resistance, and aging resistance. This is mainly because during coating formation, the salt spray resistant additive powder dissolved and dispersed in the resin system forms a dense and continuous film structure on the coating surface, effectively isolating the external salt spray environment from the main equipment structure. Furthermore, the salt spray resistant additives enhance the coating's elasticity and flexibility, making the coating... It can better resist stress damage in salt spray environment, and the coating is not prone to local peeling; sodium lignin sulfate is a versatile natural polymer compound. It can not only be used as an aggregate to improve the wear resistance of the molded paint film, but also has many active functional groups, such as hydroxyl, carboxyl and sulfonic acid groups. These functional groups enable sodium lignin sulfate to form coordination bonds with metal ions, thereby improving the adhesion between the paint film and the metal, so that the paint film can adhere more tightly to the metal surface and is not easy to fall off, thus making the paint film have a better anti-salt spray effect.

[0199] The para-alkyl-substituted phenolic resin and resin modifiers in salt spray resistant additives significantly affect the effectiveness of the additives. When ordinary epoxy resin is used to replace the para-alkyl-substituted phenolic resin in the formulation, the performance parameters of the molded coating film decrease significantly. This is because the para-alkyl-substituted phenolic resin has alkyl substitution at the para-position of the phenolic hydroxyl group in its reactant, resulting in only two reaction sites at the ortho-position on the phenolic ring. Therefore, it can obtain a regular linear structure after the phenolic condensation reaction. The hydroxyl groups in the para-alkyl-substituted phenolic resin and the hydroxyl groups in the bisphenol A type epoxy resin combine, removing one molecule of water to form an ether bond. Subsequently, the hydroxymethyl group in the phenolic resin and the terminal epoxy group in the bisphenol A type epoxy resin undergo a ring-opening reaction to form a three-dimensional structure. This complex structure endows the modified resin with good adhesion and toughness. The introduction of hydrophobic alkyl substituents can improve the hydrophobicity of the resin, enabling the cured product to maintain good electrical insulation properties even in harsh environments with high temperature and humidity.

[0200] Moreover, the preparation process of salt spray resistant additives is closely related to their performance. When using the traditional one-time mixing and crosslinking process, the optimal crosslinking temperature range for different crosslinking agents is different, which leads to insufficient crosslinking of elastic polymers and insufficient embedding of other inorganic fillers into the crosslinking network, resulting in a decline in the performance of salt spray resistant additives.

[0201] In summary, the salt spray resistant additive of the present invention, when added to existing anti-corrosion coating systems, can effectively improve the salt spray resistance and impact resistance of the formed paint film, and also enhance the adhesion, abrasion resistance and anti-aging ability of the paint film.

[0202] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A salt spray resistant additive, characterized in that: It is composed of powder with a particle size of 5-15 micrometers. The powder, by mass parts, includes 60-80 parts of elastomer microparticles, 20-30 parts of inorganic filler, 5-10 parts of para-alkyl substituted phenolic resin, 3-5 parts of resin modifier, 5-10 parts of sodium lignin sulfate, 3-5 parts of zinc oxide, 1-2 parts of diammonium phosphate, and 1-2 parts of coupling agent. The elastomer microparticles are a three-dimensional network structure formed by cross-linking of C5H8, C8H8, and C4H6 monomers; The resin modifier is prepared by the following method: Polydimethylsiloxane was added to ethanol to prepare a polydimethylsiloxane solution with a concentration of 2-5 wt%. Bisphenol A epoxy resin is heated to 40-50°C and then added dropwise to a polydimethylsiloxane solution. During the addition process, mechanical stirring is performed to ensure that the polydimethylsiloxane and bisphenol A epoxy resin are fully mixed. Dibutyltin dilaurate is added and stirred evenly. The mixed solution is then placed in a temperature environment of 110-130°C to allow for a complete reaction, and the ethanol in the mixed solution is allowed to evaporate to obtain the resin modifier. The mass ratio of bisphenol A epoxy resin, polydimethylsiloxane, and dibutyltin dilaurate is 100:80-85:1-2. The salt spray resistant additive is prepared by the following method: Step S1: Take natural rubber, styrene-butadiene rubber and cis-butadiene rubber and mix them in a mass ratio of 4:2:

1. Add para-alkyl-substituted phenolic resin, resin modifier and 1 / 2 inorganic filler and knead at 120-140℃ for 5-30 minutes to obtain mixture A. Step S2: Mix the remaining inorganic filler with zinc oxide, sodium lignin sulfate, diammonium phosphate and coupling agent, and stir in a sealed environment at 33-40℃ to obtain the modifier. Step S3: Mix mixture A and the modifier at 160-180℃ for 5-15 minutes to obtain mixture B; Step S4: Extrude and granulate the mixture B to obtain a primary raw material with a particle size of no more than 1 cm. Then, crush the primary raw material into primary powder with a particle size of 20-50 mesh. Step S5: Grind the primary powder at -80℃ to -196℃ to produce a powder of 5-15 micrometers to obtain the salt spray resistant additive.

2. The salt spray resistant additive according to claim 1, characterized in that: The inorganic filler includes mica powder, silica, and any one or more of nano-calcium carbonate, nano-montmorillonite, and nano-kaolin.

3. The salt spray resistant additive according to claim 2, characterized in that: The mica powder has a particle size of 1-5 micrometers.

4. The salt spray resistant additive according to claim 2, characterized in that: The coupling agent is a silane coupling agent.

5. The salt spray resistant additive according to claim 1, characterized in that: The reaction time of the mixed solution at a temperature of 110-130℃ is 1-2 hours.

6. The salt spray resistant additive according to claim 1, characterized in that: In step S1, before mixing natural rubber, styrene-butadiene rubber, and cis-butadiene rubber, the natural rubber is pretreated, and the pretreatment includes: (1) Drying: Place the natural rubber in an environment of 50°C to 60°C to dry it; (2) Cut into pieces: Cut the dried natural rubber into small pieces with a diameter of no more than 10 cm. (3) Plasticizing: Adjust the roller gap of the open mill, add the cut natural rubber into the open mill, and extrude the natural rubber into uniform thin sheets.

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