Composite organic silicon anticorrosive paint and preparation method thereof

Abstract

The invention belongs to the technical field of coatings, and particularly relates to a composite organic silicon anticorrosive coating and a preparation method thereof.The composite organic silicon anticorrosive coating further comprises the following raw materials in parts by weight besides a solvent: 80-95 parts of phenolic epoxy modified organic silicon resin; 1.4 to 3.5 parts of an amine curing agent; 0.08 part to 0.19 part of lithium chloride; 23 parts to 36 parts of filler; the amine curing agent comprises polyamine. According to the composite organic silicon anticorrosive paint disclosed by the invention, under the action of the amine curing agent containing polyamine and lithium chloride, the phenolic epoxy modified organic silicon resin and the filler are mixed and coated on a metal surface, and cross-linking curing of phenolic epoxy molecular chain extension and cross-linking curing of phenolic epoxy molecular chain branch linkage are uniformly carried out; the composite organic silicon anticorrosive coating with excellent impact resistance, hardness and adhesive force is formed.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a composite organosilicon anticorrosive coating and a preparation method thereof. Background Art

[0002] Organic silicon anti-corrosion coatings are coatings that use organic silicon resin as the main organic phase and are mixed with fillers. Since organic silicon resin is the main component of the organic phase, organic silicon anti-corrosion coatings have better advantages in corrosion resistance, high and low temperature resistance, and insulation than other organic coatings.

[0003] However, because silicone anti-corrosion coatings use silicone resin as the main component of the organic phase, the adhesion to the metal surface after curing is insufficient and weak. At the same time, the cured coating of silicone anti-corrosion coatings lacks impact resistance and hardness compared to metals. When the painted components are impacted, the metal relies on its own toughness, hardness and ductility to avoid damage, while the cured coating of silicone anti-corrosion coatings cracks, peels off, and becomes hollow under impact, which directly reduces the anti-corrosion effect and anti-corrosion time of the silicone anti-corrosion coatings.

[0004] Therefore, there is an urgent need to provide an organosilicon anti-corrosion coating that is more tightly bonded to metal and has better impact resistance. Summary of the invention

[0005] The main purpose of the present invention is to provide a composite organosilicon anti-corrosion coating and a preparation method thereof. In the composite organosilicon anti-corrosion coating of the present invention, a phenolic epoxy modified silicone resin and a filler are mixed and coated on a metal surface under the action of an amine curing agent containing a polyamine and lithium chloride, and cross-linking and curing of extending the phenolic epoxy molecular chain and cross-linking and curing of branching between the phenolic epoxy molecular chains occur uniformly, forming a composite organosilicon anti-corrosion coating with excellent impact resistance, hardness and adhesion.

[0006] The first aspect of the present invention provides a composite organosilicon anti-corrosion coating, which, in addition to a solvent, also includes the following raw materials in parts by weight: 80 to 95 parts of phenolic epoxy modified silicone resin; 1.4 to 3.5 parts of amine curing agent; 0.08 to 0.19 parts of lithium chloride; 23 to 36 parts of filler; the amine curing agent includes a polyamine.

[0007] In some embodiments of the present invention, the polyamine is selected from hexylene diamine and meta-xylylenediamine.

[0008] In some embodiments of the present invention, the amine curing agent further includes a monoamine, and the molar ratio of the polyamine to the monoamine is (0.8-1.1):3.

[0009] In some embodiments of the present invention, the monoamine is selected from isobutylamine and n-butylamine.

[0010] In some embodiments of the present invention, the filler is selected from silicon carbide.

[0011] In some embodiments of the present invention, the solvent includes cyclohexanone and xylene.

[0012] In some embodiments of the present invention, the raw materials of the composite organosilicon anti-corrosion coating further include 0.8 to 2.4 parts of dicyanate.

[0013] In some embodiments of the present invention, the dicyanate is selected from one of 1,1-bis(4-phenylcyanate)ethane and 2,2-bis(4-cyanophenyl)butane.

[0014] The second aspect of the present invention provides a method for preparing the composite organosilicon anti-corrosion coating according to the first aspect, the preparation method comprising: weighing each raw material in parts by weight and mixing them evenly to prepare the composite organosilicon anti-corrosion coating.

[0015] In some embodiments of the present invention, the preparation method includes: mixing phenolic epoxy modified silicone resin, filler and solvent to obtain material A; mixing amine curing agent, lithium chloride and solvent to obtain material B; mixing material A and material B evenly to obtain the composite silicone anti-corrosion coating.

[0016] In some embodiments of the present invention, dicyanate is mixed with an amine curing agent, lithium chloride and a solvent to obtain material B.

[0017] Beneficial effects of the present invention:

[0018] 1. In the present invention, under the action of an amine curing agent containing a polyamine and lithium chloride, a phenolic epoxy modified silicone resin is mixed with a filler and coated on a metal surface, and cross-linking curing of extending the phenolic epoxy molecular chain and cross-linking curing of branched bonds between the phenolic epoxy molecular chains occur evenly, forming a composite silicone anti-corrosion coating with excellent impact resistance, hardness and adhesion.

[0019] 2. In the present invention, by adding dicyanate, the impact resistance of the composite organosilicon anti-corrosion coating cured film layer is improved, and the high temperature resistance of the composite organosilicon anti-corrosion coating cured film layer is further improved.

[0020] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. DETAILED DESCRIPTION

[0021] The exemplary embodiments of the present invention will be described in more detail below with reference to specific embodiments. It should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the description and claims of the present invention and any variations thereof are intended to cover non-exclusive inclusions.

[0023] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] In the description of the embodiments of the present invention, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0026] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0027] The composite organosilicon anticorrosive coating provided by the present invention comprises, in addition to a solvent, the following raw materials in parts by weight: 80 to 95 parts of phenolic epoxy modified organosilicon resin; 1.4 to 3.5 parts of amine curing agent; 0.08 to 0.19 parts of lithium chloride; and 23 to 36 parts of filler; wherein the amine curing agent comprises a polyamine.

[0028] In the embodiments of the present invention, compared with silicone resin, the bonding force between the phenolic epoxy modified silicone resin and the metal surface is significantly improved, so that the adhesion of the cured film layer of the composite silicone anti-corrosion coating is enhanced, and the introduced benzene ring group can also improve the hardness of the cured film layer of the composite silicone anti-corrosion coating.

[0029] At the same time, amine curing agents containing polyamines and lithium chloride are added. The polyamines can not only initiate the ring opening of phenolic epoxy modified silicone resin and the crosslinking extending along the epoxy phenolic molecular chains, but also cause branched crosslinking between epoxy phenolic molecular chains bonded to different silicone molecular chains. The impact resistance of the cured film layer of the composite silicone anti-corrosion coating with a large distribution of such crosslinking structures can be significantly improved.

[0030] At the same time, the amino group in the amine curing agent is complexed with lithium chloride, delaying the reaction of the amino group with the phenolic epoxy modified silicone resin, so that the amine curing agent is evenly distributed in the composite silicone anti-corrosion coating, initiating the epoxy ring-opening and subsequent chain polymerization reaction. The composite silicone anti-corrosion coating can be cured by homogenized cross-linking reaction, the degree of branched cross-linking is controllable, and the tension force in the film layer is uniform, avoiding the uneven distribution of the branched cross-linking structure, which leads to uneven stress in the film layer and decreased impact resistance.

[0031] In summary, in the composite organosilicon anti-corrosion coating of the present invention, under the action of an amine curing agent containing a polyamine and lithium chloride, a phenolic epoxy modified silicone resin is mixed with a filler and coated on a metal surface, and cross-linking curing of extending the phenolic epoxy molecular chain and cross-linking curing of branched bonds between the phenolic epoxy molecular chains occur evenly, forming a composite organosilicon anti-corrosion coating with excellent impact resistance, hardness and adhesion.

[0032] In an embodiment of the present invention, the weight proportions of the phenolic epoxy modified silicone resin provided by the present invention can be one of 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, 85 parts, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts or any value satisfying the above range.

[0033] In an embodiment of the present invention, the weight proportions of the amine curing agent provided by the present invention can be 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts, 2.8 parts, 2.9 parts, 3 parts, 3.1 parts, 3.2 parts, 3.3 parts, 3.4 parts, 3.5 parts or any value satisfying the above range.

[0034] In an embodiment of the present invention, the weight proportion of lithium chloride provided by the present invention can be one of 0.08 parts, 0.09 parts, 0.1 parts, 0.1 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts or any value satisfying the above range.

[0035] In an embodiment of the present invention, the weight proportions of the filler provided by the present invention can be one of 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts or any value satisfying the above range.

[0036] In the embodiment of the present invention, the polyamine is hexamethylenediamine. The amino group of hexamethylenediamine reacts with the epoxy group of the phenolic epoxy modified silicone resin with little steric hindrance, and the cross-linked phenolic epoxy molecular chains have a certain space for movement, and the composite silicone anti-corrosion coating has good impact resistance after curing.

[0037] In some embodiments of the present invention, the polyamine is selected from meta-xylylenediamine.

[0038] In an embodiment of the present invention, the amine curing agent further comprises a monoamine, and the molar ratio of the polyamine to the monoamine is (0.8-1.1): 3. Exemplarily, the molar ratio of the polyamine to the monoamine may be one of 0.8:3, 0.9:3, 1:3, 1.1:3, or any value satisfying the above range.

[0039] The phenolic epoxy modified silicone resin is formed by the branched cross-linking between the phenolic epoxy molecular chains initiated by polyamines. As the content of the branched cross-linking structure in the cured film layer of the composite silicone anti-corrosion coating increases, the impact resistance of the cured film layer is improved. However, when the content of the branched cross-linking structure exceeds a threshold, the molecular chain activity in the cured film layer is excessively restricted, and the impact resistance of the cured film layer decreases. Therefore, the usage ratio of the polyamine to the phenolic epoxy modified silicone resin affects the performance of the cured film layer of the composite silicone anti-corrosion coating of the present invention.

[0040] When polyamine is used as the only amine curing agent, the curing time of the coating is slow when the concentration is below the polyamine addition threshold. Therefore, the amine curing agent is compounded with a molar ratio of polyamine to monoamine of (0.8-1.1):3. This not only ensures the effect of polyamine on improving the impact resistance of the cured film layer, but also accelerates the curing speed of the composite silicone anti-corrosion coating, reduces the difference in curing speed between the inside and outside of the coating, and can further improve the impact resistance of the cured film layer.

[0041] In an embodiment of the present invention, the monoamine is selected from isobutylamine. The amino group of isobutylamine has high reactivity and is easy to react with the epoxy group in the phenolic epoxy modified silicone resin. After the isobutylamine is connected, the steric hindrance of the epoxy group reaction on the phenolic epoxy molecular chain on both sides of the connection site is affected, and the reaction of the polyamine with the epoxy group adjacent to the isobutylamine connection site is hindered, so that the branched cross-linking structure initiated by the polyamine is more evenly distributed, and the impact resistance of the cured film layer is better.

[0042] In some embodiments of the present invention, the monoamine is selected from n-butylamine.

[0043] In some embodiments of the present invention, the novolac epoxy modified silicone resin is prepared by reacting a novolac epoxy resin with a hydroxyl-terminated phenyl silicone oil.

[0044] In some embodiments of the present invention, the novolac epoxy modified silicone resin is prepared by reacting a novolac epoxy resin with a hydroxy silicone oil.

[0045] In an embodiment of the present invention, the filler is selected from silicon carbide.

[0046] In an embodiment of the present invention, the solvent includes cyclohexanone and xylene.

[0047] In an embodiment of the present invention, the raw materials of the composite organosilicon anti-corrosion coating further include 0.8 to 2.4 parts of dicyanate.

[0048] In the embodiments of the present invention, dicyanate forms a heat-resistant 1,3,5-triazine ring through self-polymerization, and then reacts with an epoxy group and rearranges to form an alkyl isocyanate, or directly reacts with an epoxy group through an OCN group and then rearranges to form an oxazolone ring, thereby playing the role of a cross-linking agent, a reinforcing agent, and a high-temperature resistant agent, thereby improving the impact resistance, hardness, and adhesion of the cured film layer of the composite organosilicon anti-corrosion coating, and further improving the high-temperature resistance of the cured film layer of the composite organosilicon anti-corrosion coating.

[0049] The weight proportion of the dicyanate provided by the present invention can be one of 0.8 parts, 0.9 parts, 1 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts or any value satisfying the above range.

[0050] In an embodiment of the present invention, the dicyanate is selected from 1,1-bis(4-phenylcyanate)ethane.

[0051] In some embodiments of the present invention, the dicyanate is selected from 2,2-bis(4-cyanophenyl)butane.

[0052] By adopting the above raw materials, the composite organosilicon anti-corrosion coating cured film layer obtained by the present invention has better adhesion and impact resistance.

[0053] The present invention also provides a method for preparing the composite organosilicon anti-corrosion coating. The key to the preparation method is to evenly mix the raw materials for forming the composite organosilicon anti-corrosion coating to obtain the composite organosilicon anti-corrosion coating.

[0054] The preparation method of the composite organosilicon anti-corrosion coating of the present invention is specifically carried out according to the following steps.

[0055] 1) Mixing a phenolic epoxy modified silicone resin, a filler and a solvent to obtain a material A.

[0056] 2) Mixing an amine curing agent, lithium chloride and a solvent to obtain material B.

[0057] 3) Mix material A and material B evenly to obtain a composite organosilicon anti-corrosion coating.

[0058] In an embodiment of the present invention, by adopting the above preparation process, lithium chloride is first mixed with an amine curing agent, which is beneficial to the complexation of amino groups and lithium chloride, so that the composite silicone anti-corrosion coating can be better cured by homogenization cross-linking reaction, and the resulting cured film layer has better impact resistance.

[0059] In some embodiments of the present invention, the preparation method of the composite organosilicon anti-corrosion coating is specifically carried out according to the following steps.

[0060] 1) Mixing a phenolic epoxy modified silicone resin, a filler and a solvent to obtain a material A.

[0061] 2) Mixing an amine curing agent, lithium chloride, dicyanate and a solvent to obtain material B.

[0062] 3) Mix material A and material B evenly to obtain a composite organosilicon anti-corrosion coating.

[0063] In the embodiment of the present invention, by adopting the above preparation process, when dicyanate is designed to be added to the raw materials, the dicyanate should be used as one of the components of material B together with the amine curing agent to avoid premature addition to initiate polymerization of the phenolic epoxy modified silicone resin in material A.

[0064] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the amounts of the experimental reagents, unless otherwise specified, are the amounts of reagents used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0065] The phenolic epoxy resin adopts Phoenix brand F-51 linear phenolic epoxy resin.

[0066] Hydroxy-terminated phenyl silicone oil, CAS: 63148-59-4, phenyl / methyl = 1 / 4, relative molecular weight distribution is 500-600.

[0067] Hydroxy silicone oil, CAS: 70131-67-8, relative molecular weight distribution is 400-500.

[0068] Hexamethylenediamine, meta-xylylenediamine, isobutylamine, n-butylamine and lithium chloride are all commercially available industrial grade products.

[0069] The dicyanate uses 1,1-bis(4-phenylcyanate)ethane or 2,2-bis(4-cyanophenyl)butane.

[0070] Among them, 1,1-bis(4-phenylcyanate)ethane is also known as bisphenol E cyanate, CAS: 47073-92-7;

[0071] 2,2-Bis(4-cyanophenyl)butane, CAS: 38943-05-4, both are commercially available industrial grade products.

[0072] The filler is silicon carbide with a particle size of 0.2 μm.

[0073] Preparation Example 1

[0074] A phenolic epoxy modified silicone resin is prepared by reacting a phenolic epoxy resin and a hydroxyl-terminated phenyl silicone oil. The specific preparation method is as follows:

[0075] 2 kg of hydroxy-terminated phenyl silicone oil, 1.6 kg of cyclohexanone and 0.4 kg of xylene were stirred, mixed and dispersed to obtain a first material.

[0076] Adjust the temperature of the first material to 42°C, add 0.48 kg of phenolic epoxy resin and mix well, raise the temperature to 80°C, add 0.02 kg of dibutyltin dilaurate and react for 3 hours, then raise the temperature to 120°C, add 0.01 kg of dibutyltin dilaurate and continue to react for 2.5 hours, cool the material to 40°C to obtain a reaction material.

[0077] The reaction material contains phenolic epoxy modified silicone resin, cyclohexanone and xylene, wherein the content of the phenolic epoxy modified silicone resin is 55±0.5wt% based on the total mass of the reaction material being 100%.

[0078] Preparation Example 2

[0079] A phenolic epoxy modified silicone resin is prepared by reacting a phenolic epoxy resin and hydroxy silicone oil. The specific preparation method is as follows:

[0080] 2 kg of hydroxy silicone oil, 1.6 kg of cyclohexanone and 0.4 kg of xylene were stirred, mixed and dispersed to obtain a first material.

[0081] Adjust the temperature of the first material to 42°C, add 0.48 kg of phenolic epoxy resin and mix well, raise the temperature to 80°C, add 0.02 kg of dibutyltin dilaurate and react for 3 hours, then raise the temperature to 120°C, add 0.01 kg of dibutyltin dilaurate and continue to react for 2.5 hours, cool the material to 40°C to obtain a reaction material.

[0082] The reaction material contains phenolic epoxy modified silicone resin, cyclohexanone and xylene, wherein the content of the phenolic epoxy modified silicone resin is 55±0.5wt% based on the total mass of the reaction material being 100%.

[0083] Example 1

[0084] A composite organosilicon anticorrosive coating, the constituent raw materials of which include phenolic epoxy modified organosilicon resin, amine curing agent, filler, lithium chloride and solvent.

[0085] The amine curing agent is prepared by mixing hexamethylenediamine and isobutylamine in a molar ratio of 1:3.

[0086] The solvents were cyclohexanone and xylene.

[0087] The specific preparation method is as follows:

[0088] 1.636 kg of the reaction material prepared in Preparation Example 1 was mixed with 0.25 kg of filler to obtain material A. The reaction material contained phenolic epoxy modified silicone resin, cyclohexanone and xylene, wherein the content of phenolic epoxy modified silicone resin was 55±0.5 wt %.

[0089] 1.9 g of lithium chloride, 32 g of an amine curing agent, 20 g of cyclohexanone and 5 g of xylene were uniformly mixed to obtain material B. The total number of amino groups in 32 g of the amine curing agent was 0.478 mol.

[0090] Material A is stirred and material B is added, and after mixing evenly, a composite organosilicon anti-corrosion coating is obtained.

[0091] Example 2

[0092] A composite organosilicon anti-corrosion coating, which differs from Example 1 in that the reaction material is prepared by Preparation Example 2.

[0093] Example 3

[0094] A composite organosilicon anti-corrosion coating is provided, which differs from Example 1 in that the amine curing agent is obtained by compounding meta-phenylenediamine and isobutylamine in a molar ratio of 1:3, the amount of the amine curing agent used is 33.91 g, and the total number of amino groups is 0.478 mol.

[0095] Example 4

[0096] A composite organosilicon anticorrosive coating is different from Example 1 in that the amine curing agent is hexamethylenediamine, and the amount of hexamethylenediamine used is 27.72 g, that is, hexamethylenediamine is 0.239 mol, and the total number of amino groups = 2×0.239 mol = 0.478 mol.

[0097] Example 5

[0098] A composite organosilicon anti-corrosion coating, which differs from Example 1 in that the amine curing agent is a compound of hexamethylenediamine and isobutylamine in a molar ratio of 0.5:3.

[0099] Example 6

[0100] A composite organosilicon anti-corrosion coating, which differs from Example 1 in that the amine curing agent is a mixture of hexamethylenediamine and isobutylamine in a molar ratio of 0.8:3.

[0101] Example 7

[0102] A composite organosilicon anti-corrosion coating, which differs from Example 1 in that the amine curing agent is a mixture of hexamethylenediamine and isobutylamine in a molar ratio of 1.1:3.

[0103] Example 8

[0104] A composite organosilicon anti-corrosion coating, which differs from Example 1 in that the amine curing agent is a mixture of hexamethylenediamine and isobutylamine in a molar ratio of 1.6:3.

[0105] Example 9

[0106] A composite organosilicon anti-corrosion coating, which differs from Example 1 in that the amine curing agent is a mixture of hexamethylenediamine and n-butylamine in a molar ratio of 1:3.

[0107] Example 10

[0108] A composite organic silicon anticorrosive coating is different from Example 1 in that the preparation method is different. The preparation method of Example 10 is as follows:

[0109] 1.636 kg of the reaction material prepared in Preparation Example 1, 0.25 kg of filler and 1.9 g of lithium chloride were uniformly mixed to obtain material A.

[0110] Material B was obtained by uniformly mixing 32 g of an amine curing agent, 20 g of cyclohexanone and 5 g of xylene.

[0111] Material A is stirred and material B is added, and after mixing evenly, a composite organosilicon anti-corrosion coating is obtained.

[0112] Embodiment 11

[0113] A composite organosilicon anticorrosive coating, the raw materials of which include phenolic epoxy modified organosilicon resin, amine curing agent, filler, lithium chloride, dicyanate and solvent.

[0114] The amine curing agent is prepared by mixing hexamethylenediamine and isobutylamine in a molar ratio of 1:3.

[0115] The dicyanate is 1,1-bis(4-phenylcyanate)ethane.

[0116] The solvents were cyclohexanone and xylene.

[0117] The specific preparation method is as follows:

[0118] 1.636 kg of the reaction material prepared in Preparation Example 1 was mixed with 0.25 kg of filler to obtain material A. The reaction material contained phenolic epoxy modified silicone resin, cyclohexanone and xylene, wherein the content of phenolic epoxy modified silicone resin was 55±0.5 wt % based on the total mass of the reaction material being 100 %.

[0119] Material B was obtained by uniformly mixing 1.9 g of lithium chloride, 32 g of an amine curing agent, 12 g of a dicyanate, 20 g of cyclohexanone and 5 g of xylene.

[0120] Material A is stirred and material B is added, and after mixing evenly, a composite organosilicon anti-corrosion coating is obtained.

[0121] Example 12

[0122] A composite organosilicon anti-corrosion coating, which differs from Example 11 in that the dicyanate is 2,2-di(4-cyanophenyl)butane.

[0123] Embodiments 13 to 15

[0124] A composite organosilicon anti-corrosion coating, which differs from Example 11 in that the amount of materials used is different, as shown in Table 1 below.

[0125] Table 1. Material usage table of Examples 13 to 15

[0126]

[0127]

[0128] Comparative Example 1

[0129] A composite organosilicon anticorrosive coating, the constituent raw materials of which include phenolic epoxy modified organosilicon resin, amine curing agent, filler and solvent.

[0130] The amine curing agent is prepared by mixing hexamethylenediamine and isobutylamine in a molar ratio of 1:3.

[0131] The solvents were cyclohexanone and xylene.

[0132] The specific preparation method is as follows:

[0133] 1.636 kg of the reaction material prepared in Preparation Example 1 was mixed evenly with 0.25 kg of filler to obtain material A.

[0134] Material B was obtained by uniformly mixing 32 g of an amine curing agent, 20 g of cyclohexanone and 5 g of xylene.

[0135] Material A is stirred and material B is added, and after mixing evenly, a composite organosilicon anti-corrosion coating is obtained.

[0136] Comparative Example 2

[0137] A composite organosilicon anti-corrosion coating, which differs from Example 1 only in that the amine curing agent is isobutylamine.

[0138] Comparative Example 3

[0139] A composite organosilicon anticorrosive coating, the constituent materials of which include organosilicon resin, amine curing agent, filler, lithium chloride and solvent.

[0140] The organic silicone resin adopts hydroxyl-terminated phenyl silicone oil.

[0141] The amine curing agent is prepared by mixing hexamethylenediamine and isobutylamine in a molar ratio of 1:3.

[0142] The solvents were cyclohexanone and xylene.

[0143] The specific preparation method is as follows:

[0144] 0.9 kg of hydroxy-terminated phenyl silicone oil, 0.25 kg of filler, 0.589 kg of cyclohexanone and 0.147 kg of xylene were mixed uniformly to obtain material A.

[0145] Material B was obtained by uniformly mixing 1.9 g of lithium chloride, 32 g of an amine curing agent, 20 g of cyclohexanone and 5 g of xylene.

[0146] Material A is stirred and material B is added, and after mixing evenly, a composite organosilicon anti-corrosion coating is obtained.

[0147] Performance Testing

[0148] Hardness: The hardness of the paint film is measured according to the pencil method for paints and varnishes in GB / T 6739-2022. The paint film is a current layer of paint with a thickness of 400μm.

[0149] Impact resistance: The test is carried out according to GB / T 1732-2020 paint film impact resistance determination method. The substrate is tinplate, the paint film is a current layer of paint film with a thickness of 400μm.

[0150] Adhesion: tested according to the paint film circle test of GB / T 1720-2020, the substrate is tinplate, the paint film is a current layer of paint film with a thickness of 400μm.

[0151] The coatings obtained in Examples 1 to 15 and Comparative Examples 1 to 3 were used to prepare coating samples, and the hardness, impact resistance and adhesion of the cured film layers on the coating samples were tested. The test results are shown in Table 2 below.

[0152] Table 2. Performance test results of the coatings obtained in Examples 1 to 15 and Comparative Examples 1 to 3

[0153]

[0154]

[0155] It can be seen from Table 2 that compared with Comparative Examples 1 to 3, the hardness of Examples 1 to 2 is significantly harder than that of Comparative Examples 1 to 3, and at the same time, the impact resistance-drop height of Examples 1 to 2 is greater than that of Comparative Examples 1 to 3, and the adhesion level of Examples 1 to 2 is better than that of Comparative Examples 1 to 3. Therefore, the addition of lithium chloride in the present invention does indeed make the amino group in the amine curing agent complex with lithium chloride, delay the reaction of the amino group with the phenolic epoxy modified silicone resin, and make the amine curing agent evenly distributed in the composite silicone anti-corrosion coating to induce the ring-opening of the epoxy group and the subsequent chain polymerization reaction. The composite silicone anti-corrosion coating can be cured by homogenizing cross-linking reaction, the degree of branch cross-linking is controllable, and the tension force in the film layer is uniform, avoiding the uneven distribution of the branch cross-linking structure which leads to uneven stress in the film layer and decreased impact resistance. Under the action of amine curing agent containing polyamine and lithium chloride, phenolic epoxy modified silicone resin is mixed with filler and coated on the metal surface, and cross-linking curing of extending the phenolic epoxy molecular chain and cross-linking curing of branch bonding between phenolic epoxy molecular chains occur evenly, forming a composite silicone anti-corrosion coating with excellent impact resistance, hardness and adhesion.

[0156] By comparing Example 1 and Example 2, it can be seen that the hardness of Example 1 is significantly harder than that of Example 2. At the same time, the impact resistance-drop height of Example 1 is greater than that of Example 2. Therefore, the phenolic epoxy modified silicone resin is obtained by modifying the phenyl-containing silicone resin, and the final composite silicone anti-corrosion coating has better performance.

[0157] By comparing Example 1 and Example 3, it can be seen that the impact resistance-falling height of Example 1 is greater than that of Example 3. This is because the polyamine in the amine curing agent of Example 1 is hexamethylenediamine, and the steric hindrance of the reaction between the amino group on hexamethylenediamine and the epoxy group on the phenolic epoxy modified silicone resin is small. The cross-linked phenolic epoxy molecular chains have a certain amount of space for activity and movement, and the composite silicone anti-corrosion coating has better impact resistance after curing.

[0158] The phenolic epoxy modified silicone resin is formed by the branched cross-linking between the phenolic epoxy molecular chains initiated by polyamines. As the content of the branched cross-linking structure in the cured film layer of the composite silicone anti-corrosion coating increases, the impact resistance of the cured film layer is improved. However, when the content of the branched cross-linking structure exceeds a threshold, the molecular chain activity in the cured film layer is excessively restricted, and the impact resistance of the cured film layer decreases. Therefore, the usage ratio of the polyamine to the phenolic epoxy modified silicone resin affects the performance of the cured film layer of the composite silicone anti-corrosion coating of the present invention.

[0159] When polyamine is used as the only amine curing agent, the curing time of the coating is slow when the content is below the polyamine addition threshold. By comparing Example 1 and Example 4, it can be seen that the amine curing agent of Example 4 is only hexamethylenediamine, and its total amino group number is equal to the total amino group number of the amine curing agent of Example 1, but the impact resistance-falling height of Example 1 is better than that of Example 4. Therefore, in the present invention, polyamine and monoamine are compounded as amine curing agents to ensure the effect of polyamine on improving the impact resistance of the cured film layer, and to accelerate the curing speed of the composite silicone anti-corrosion coating, reduce the difference in curing speed inside and outside the coating, and further improve the impact resistance of the cured film layer.

[0160] Combined with Example 1 and Examples 5 to 8, it can be seen that the proportion of polyamine in the amine curing agent of Example 5, Example 6, Example 1, Example 7, and Example 8 gradually increases, and its hardness increases with the increase in the proportion of polyamine, but its impact resistance-drop height reaches the best in Example 1 and Example 6, and the impact resistance-drop height decreases in Examples 7 and 8 where the proportion of polyamine is larger. Therefore, when the polyamine is compounded in the present invention, the molar ratio of polyamine to monoamine is (0.8 to 1.1): 3, and the compounding effect is better.

[0161] In combination with Example 1 and Example 9, the monoamine selected in Example 1 is isobutylamine. Compared with the n-butylamine in Example 9, the carbon chain structure of isobutylamine affects the steric hindrance of the epoxy groups on the phenolic epoxy molecular chains on both sides of the access site after the reaction access, hinders the reaction of the polyamine with the epoxy groups adjacent to the isobutylamine access site, and makes the distribution of the branched cross-linked structure initiated by the polyamine in Example 1 more uniform than that in Example 9. The impact resistance of the cured film layer of Example 1 is better, so the impact resistance-drop height of Example 1 is better than that of Example 9.

[0162] Since the effect of lithium chloride needs to be complexed with amino groups to be effective, when preparing the composite silicone coating of the present invention, the lithium chloride is first mixed with the amine curing agent and then mixed with the phenolic epoxy modified silicone resin, so that the effect of lithium chloride can be maximized. Therefore, the hardness of Example 1 is better than that of Example 10, and the impact resistance-drop height of Example 1 is greater than that of Example 11.

[0163] By comparing Example 1 with Examples 11 to 12, it can be seen that compared with Example 1, dicyanate is further added to material B in Examples 11 to 12. The dicyanate can form a 1,3,5-triazine ring through self-polymerization, and then react with the epoxy matrix to rearrange to form an alkyl isocyanate, or directly react with the epoxy group through the OCN group and rearrange to form an oxazolone ring, which plays a cross-linking and strengthening role, and can simultaneously improve the hardness, impact resistance, and adhesion of the cured film layer of the composite silicone anti-corrosion coating. Therefore, the hardness and adhesion grades of Examples 11 to 12 are better than those of Example 1, and the impact resistance-drop height of Examples 11 to 12 is greater than that of Example 1.

[0164] Further comparing Examples 11 and 12, the impact resistance-drop height of Example 11 is greater than that of Example 12. In the present invention, 1,1-bis(4-phenylcyanate)ethane is preferably used as the dicyanate.

[0165] In combination with Example 11 and Examples 13 to 15, it can be seen that the mass ratio of the raw materials used in the composite organosilicon anti-corrosion coating of the present invention is controlled as phenolic epoxy modified silicone resin: amine curing agent: filler: lithium chloride: dicyanate = (80 to 95): (1.4 to 3.5): (23 to 36): (0.08 to 0.19): (0.8 to 2.4), and the cured film layer formed by the obtained composite organosilicon anti-corrosion coating has excellent hardness, impact resistance and adhesion.

[0166] In addition, the present invention also conducted a heat resistance test on Example 1 and Examples 11-12.

[0167] Heat resistance test: The sample uses a 120mm×50mm×0.3mm tinplate (in accordance with the technical requirements of GB9271) as the base plate, and the coating is applied on a 120mm×50mm to form a cured film layer with a thickness of 400μm. Make multiple samples, first store them at room temperature for 120h, then store them at 400℃, 450℃, 500℃, and 550℃ for 10h, and then remove them to observe whether there are bubbles, pores, cracks, and peeling. If there are none, it is qualified at the current storage temperature. The results are expressed by the highest storage temperature among the qualified results of the samples, as shown in the table below.

[0168] Table 3. Heat resistance test results of the coatings in Example 1 and Examples 11 to 12

[0169] Group The highest storage temperature among qualified results / ℃ Example 1 500 Embodiment 11 550 Example 12 550

[0170] It can be seen from Table 3 that the highest storage temperature in the qualified results of Examples 11 to 12 is higher than that of Example 1. The addition of dicyanate in Examples 11 to 12 can also provide heat resistance for the cured film layer of the composite organosilicon anti-corrosion coating.

[0171] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A composite organosilicon anti-corrosion coating, characterized in that: The composite organosilicon anticorrosive coating includes the following raw materials in parts by weight in addition to the solvent: 80 to 95 parts of phenolic epoxy modified silicone resin; 1.4 to 3.5 parts of amine curing agent; 0.08 to 0.19 parts of lithium chloride; 23 to 36 parts of filler; The amine curing agent includes polyamine.

2. The composite organosilicon anticorrosive coating according to claim 1, characterized in that: The polyamine is selected from hexylene diamine and meta-xylene diamine.

3. The composite organosilicon anticorrosive coating according to claim 1, characterized in that: The amine curing agent also includes a monoamine, and the molar ratio of the polyamine to the monoamine is (0.8-1.1):

3.

4. The composite organosilicon anticorrosive coating according to claim 3, characterized in that: The monoamine is selected from isobutylamine and n-butylamine.

5. The composite organosilicon anticorrosive coating according to claim 1, characterized in that: The filler is selected from silicon carbide; Preferably, the solvent comprises cyclohexanone and xylene.

6. The composite organosilicon anticorrosive coating according to claim 1, characterized in that: The raw materials of the composite organosilicon anti-corrosion coating also include 0.8 to 2.4 parts of dicyanate.

7. The composite organosilicon anticorrosive coating according to claim 6, characterized in that: The dicyanate is selected from one of 1,1-bis(4-phenylcyanate)ethane and 2,2-bis(4-cyanophenyl)butane.

8. A method for preparing the composite organosilicon anticorrosive coating according to any one of claims 1 to 7, characterized in that: The preparation method comprises: weighing various raw materials in parts by weight and mixing them evenly to prepare the composite organic silicon anticorrosive coating.

9. The preparation method according to claim 8, characterized in that: The preparation method comprises: Mixing phenolic epoxy modified silicone resin, filler and solvent to obtain material A; Mixing an amine curing agent, lithium chloride and a solvent to obtain material B; The material A and the material B are mixed evenly to obtain the composite organosilicon anti-corrosion coating.

10. The preparation method according to claim 9, characterized in that: The dicyanate is mixed with an amine curing agent, lithium chloride and a solvent to obtain material B.

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