Underwater-curable epoxy resin amine curing agent

Abstract

The invention relates to the technical field of epoxy resin, in particular to an epoxy resin amine curing agent capable of being cured underwater, which comprises the following components: alicyclic amine, phenolic substances, paraformaldehyde and benzyl alcohol, the alicyclic amine is one or more of isophorone diamine (IPDA), m-xylylenediamine (MXDA), 1, 3-cyclohexanedimethylamine (1, 3Bac), 4, 4-diamino dicyclohexylmethane (PACM) and 1, 2-cyclohexanediamine (DCH-99), and the phenolic substances are one or more of isophorone diamine (IPDA), m-xylylenediamine (MXDA), 1, 3-cyclohexanedimethylamine (1, 3Bac), 4, 4-diamino dicyclohexylmethane (PACM) and 1, 2-cyclohexanediamine (DCH-99). Two alicyclic amines are subjected to Mannich reaction respectively and then mixed, the obtained product meets the underwater construction condition, the low-temperature curing performance of phenolic aldehyde amine is kept, the introduced alicyclic amines have excellent mechanical performance after phenolic aldehyde reaction, and therefore the adhesive strength and weather resistance are improved, and the adhesive has a good application prospect. The paint has the advantages of good corrosion resistance, light color, high gloss, good weather resistance and the like.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy resins, in particular to a high-performance anticorrosive epoxy resin amine curing agent capable of underwater curing. Background Art

[0002] When epoxy resin is cured, it reacts chemically with epoxy resin curing agent to form a three-dimensional network polymer. Amine curing agents are the most commonly used type of epoxy resin curing agent. Traditional phenolic amine curing agents cannot form a three-dimensional network structure with epoxy resin underwater due to the strong hydrophilicity of the vinylamine group in its structure, and cannot be completely cured. In addition, its use time is short and the reaction speed is fast, resulting in poor flexibility and impact resistance of the cured paint film, and poor adhesion to metal substrates, especially special metal substrates. Summary of the invention

[0003] The purpose of the present invention is to provide an epoxy resin amine curing agent that can be cured underwater in view of the shortcomings of the prior art. The alicyclic amine introduced into the curing agent has strong hydrophobicity and low water absorption, can meet underwater construction conditions, and has excellent bonding performance and excellent anti-corrosion performance.

[0004] The technical solution adopted by the present invention to solve the technical problem is: an underwater curable epoxy resin amine curing agent, which comprises the following components: alicyclic amine, phenolic substances, polyformaldehyde, and benzyl alcohol, wherein the alicyclic amine is one or more of isophorone diamine (IPDA), meta-phenylenediamine (MXDA), 1,3-cyclohexanedimethylamine (1,3Bac), 4,4-diaminodicyclohexylmethane (PACM), and 1,2-cyclohexanediamine (DCH-99); the phenolic substances are one or more of phenol, cardanol, p-tert-butylphenol, nonylphenol, and dodecylphenol; and the alicyclic amine, phenolic substances, polyformaldehyde, and benzyl alcohol are in a molar ratio of 1:1:1-1.1:0.8-1 according to the mass.

[0005] Preferably, the alicyclic amine includes: 80-110 g of m-phenylenediamine, 60-100 g of 4,4-diaminodicyclohexylmethane, and the phenolic substance includes: 94 g of phenol.

[0006] The preparation method of the epoxy resin amine curing agent capable of underwater curing of the present invention comprises the following steps:

[0007] S1: preparing phenalkamine A, adding an alicyclic amine, phenolic substances and benzyl alcohol into a reaction kettle, stirring evenly and heating to 70°C, stopping heating, slowly adding paraformaldehyde, controlling the temperature not to exceed 90°C, and maintaining the temperature at 80°C for 4-5 hours after the addition, and then vacuum dehydrating until transparent and clear to obtain phenalkamine A; the alicyclic amine is m-xylylenediamine, the phenolic substance is phenol, and the reaction equation is:

[0008] S2: Prepare phenolic amine B, add another alicyclic amine, phenolic substances and benzyl alcohol into a reaction kettle, stir evenly and heat to 80°C, stop heating, slowly add polyformaldehyde, control the temperature not to exceed 90°C, keep the temperature at 85°C for 4-5 hours after adding, and then dehydrate under vacuum pressure until transparent and clear to obtain phenolic amine B; the alicyclic amine is 4,4-diaminodicyclohexylmethane, the phenolic substance is phenol, and the reaction equation is:

[0009] S3: Mixing: Mix the phenalkamine A and phenalkamine B obtained in S1 and S2, stir evenly, and obtain a product.

[0010] The epoxy resin amine curing agent capable of underwater curing of the present invention has an amine value of 280-320 mgKOH / g and an active hydrogen equivalent of 130-150 g / mol.

[0011] The beneficial effects of the present invention are as follows: the alicyclic amine introduced in the novel epoxy resin amine curing agent of the present invention has strong hydrophobicity and low water absorption, and can be quickly cured underwater, thereby meeting underwater construction conditions; the alicyclic amine not only maintains the low-temperature curing performance of the phenolic amine, but also the introduced alicyclic amine has excellent mechanical properties after the phenolic aldehyde reaction, thereby improving the adhesion and weather resistance, having the advantages of good anti-corrosion performance, light color, high gloss, good weather resistance, etc., and is suitable for underwater curing anti-corrosion coatings, floor coatings, and bonding and repairing of underwater buildings. DETAILED DESCRIPTION

[0012] The present invention will be further described in detail below in conjunction with specific embodiments, but the implementation scope of the present invention is not limited thereto.

[0013] The raw materials used in the examples of the present application are all commercially available industrial-grade products, and each component is measured by weight.

[0014] Example 1.

[0015] The epoxy resin amine curing agent that can be cured underwater in this embodiment includes the following components: alicyclic amine, phenolic substances, polyformaldehyde, and benzyl alcohol, wherein the alicyclic amine is 1,3-phenylenediamine (i.e., m-phenylenediamine) and 4,4-diaminodicyclohexylmethane, and the phenolic substance is phenol. Among them, 1,3-phenylenediamine 81.6g, 4,4-diaminodicyclohexylmethane 84g, phenol 94g, polyformaldehyde 30g, and benzyl alcohol 209.6g.

[0016] The preparation method thereof comprises the following steps:

[0017] S1: Prepare phenolic amine A. Add 56.4 g of phenol, 81.6 g of 1,3-phenylenediamine, and 100 g of benzyl alcohol into a reaction kettle, stir evenly, and heat to 70°C. Stop heating, slowly add 18 g of paraformaldehyde, and control the temperature not to exceed 90°C. After adding, keep the temperature at 80°C for 4-5 hours, and then dehydrate under vacuum pressure until transparent and clear to obtain phenolic amine A.

[0018] S2: Prepare phenolic amine B. Add 37.6 g of phenol, 84 g of 4,4-diaminodicyclohexylmethane, and 109.6 g of benzyl alcohol into a reactor. Stir evenly and heat to 80°C. Stop heating and slowly add 12 g of paraformaldehyde. Control the temperature not to exceed 90°C. After adding, keep the temperature at 85°C for 4-5 hours. Then, dehydrate under vacuum and negative pressure until transparent and clear to obtain phenolic amine B.

[0019] S3 mixing: evenly mix the phenolic amine A and phenolic amine B obtained in S1 and S2 to obtain a high-toughness epoxy amine curing agent that can be cured underwater.

[0020] The performance of the curing agent prepared above was tested, and the results were as follows: transparent liquid, color 5-6 (iron-cobalt method), amine value 289, viscosity 7000cps (25°C), gel time 22min (25°C), surface dry 2hr (25°C), actual dry 4.5hr (25°C), adhesion level 0, 50kg.cm impact qualified, hardness 2H.

[0021] In this embodiment, two alicyclic amines are used to undergo Mannich reaction respectively and then mixed. 1,3-phenylenediamine (MXDA) is an aliphatic amine containing an aromatic ring, which has good hydrophobicity and can be cured with epoxy resin underwater, and has good water-based low-temperature curing effect. 4,4-diaminodicyclohexylmethane (PACM) has excellent hydrophobicity and slow reaction speed with epoxy resin, but it can increase the reaction speed after phenolization, and at the same time improve the wettability of multiple substrates, and underwater curing can maintain a high gloss. It also has good weather resistance and flexibility, excellent mechanical properties and adhesion.

[0022] Embodiment 2.

[0023] Compared with Example 1, this example contains 95.2 g of 1,3-phenylenediamine, 63 g of 4,4-diaminodicyclohexylmethane, 94 g of phenol, 30 g of paraformaldehyde, and 179.28 g of benzyl alcohol.

[0024] The amounts of the raw materials in S1 are: 65.8 g of phenol, 95.2 g of 1,3-phenylenediamine, 21 g of polyformaldehyde, and 131.2 g of benzyl alcohol; the amounts of the raw materials in S2 are: 28.2 g of phenol, 63 g of 4,4-diaminodicyclohexylmethane, 9 g of polyformaldehyde, and 48.08 g of benzyl alcohol.

[0025] The rest is the same as that of the first embodiment and will not be described again.

[0026] The results are as follows: transparent liquid, color No. 5-6 (iron-cobalt method), amine value 289, viscosity 8300cps (25℃), gel time 15min (25℃), surface dry 1.5hr (25℃), actual dry 3.5hr (25℃), adhesion level 0, 50cm.kg impact qualified, hardness 2H.

[0027] Embodiment three.

[0028] Compared with Example 1, this example contains 108.8 g of 1,3-phenylenediamine, 42 g of 4,4-diaminodicyclohexylmethane, 94 g of phenol, 36 g of paraformaldehyde, and 190.08 g of benzyl alcohol.

[0029] The amounts of the raw materials in S1 are: 75.2 g of phenol, 108.8 g of 1,3-phenylenediamine, 24 g of polyformaldehyde, and 111.2 g of benzyl alcohol; the amounts of the raw materials in S2 are: 18.8 g of phenol, 42 g of 4,4-diaminodicyclohexylmethane, 12 g of polyformaldehyde, and 78.88 g of benzyl alcohol.

[0030] The results are as follows: transparent liquid, color No. 5-6 (iron-cobalt method), amine value 289, viscosity 13000cps (25℃), gel time 13min (25℃), surface dry 1hr (25℃), actual dry 3hr (25℃), adhesion level 0, 50cm.kg impact qualified, hardness 2H.

[0031] The above-mentioned Examples 1, 2, and 3 were mixed with commercially available epoxy adhesive A, and cured under distilled water at 20, 40, and 60° C. and at room temperature, and then subjected to water absorption test, steel plate tensile strength test (underwater curing for 7 days), and mechanical strength test.

[0032] The test results are as follows: Test items Example 1 Example 2 Example 3 Status in container qualified qualified qualified Mixed state (de-vacuumed) Uniform, no bubbles Uniform, no bubbles Uniform, no bubbles Water absorption (in distilled water at 20℃) <1％ <1％ <1％ Water absorption (in distilled water at 40℃) <1％ <1％ <1％ Water absorption (in distilled water at 60℃) <2％ <2％ <2％ Tensile strength (7 days underwater curing) >45MPa qualified >45MPa qualified >45MPa qualified Flexural strength (7 days underwater curing) >80MPa qualified >80MPa qualified >80MPa qualified

[0033] The above-mentioned Examples 1, 2, and 3 were mixed with commercially available epoxy anticorrosive coating material A to make panels, and the performance indicators were tested after curing. The test results are as follows:

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. An epoxy resin amine curing agent capable of underwater curing, characterized in that: The invention comprises the following components: alicyclic amine, phenolic substances, polyformaldehyde and benzyl alcohol, wherein the alicyclic amine is one or more of isophorone diamine (IPDA), meta-phenylenediamine (MXDA), 1,3-cyclohexanedimethylamine (1,3Bac), 4,4-diaminodicyclohexylmethane (PACM) and 1,2-cyclohexanediamine (DCH-99); the phenolic substances are one or more of phenol, cardanol, p-tert-butylphenol, nonylphenol and dodecylphenol; and the alicyclic amine, phenolic substances, polyformaldehyde and benzyl alcohol have a molar ratio of 1:1:1-1.1:0.8-1 according to the mass.

2. The underwater curable epoxy resin amine curing agent according to claim 1, characterized in that: The alicyclic amine includes: 80-110 g of m-phenylenediamine and 60-100 g of 4,4-diaminodicyclohexylmethane; and the phenolic substance includes: 94 g of phenol.

3. The underwater curable epoxy resin amine curing agent according to claim 1, characterized in that: The preparation method thereof comprises the following steps: S1: preparing phenalkamine A, adding an alicyclic amine, phenolic substances and benzyl alcohol into a reaction kettle, stirring evenly and heating to 70°C, stopping heating, slowly adding paraformaldehyde, controlling the temperature not to exceed 90°C, maintaining the temperature at 80°C for 4-5 hours after the addition, and then dehydrating under vacuum and negative pressure until transparent and clear to obtain phenalkamine A; S2: preparing phenalkamine B, adding another alicyclic amine, phenolic substances and benzyl alcohol into a reaction kettle, stirring evenly and heating to 80°C, stopping heating, slowly adding paraformaldehyde, controlling the temperature not to exceed 90°C, and maintaining the temperature at 85°C for 4-5 hours after the addition, and then dehydrating under vacuum and negative pressure until transparent and clear to obtain phenalkamine B; S3: Mixing: Mix the phenalkamine A and phenalkamine B obtained in S1 and S2, stir evenly, and obtain a product.

4. The underwater curable epoxy resin amine curing agent according to claim 3, characterized in that: In S1, the alicyclic amine is meta-xylylenediamine (MXDA), and the phenolic substance is phenol; in S2, the alicyclic amine is 4,4-diaminodicyclohexylmethane, and the phenolic substance is phenol.

5. The underwater curable epoxy resin amine curing agent according to claim 3, characterized in that: Its amine value is 280-320 mgKOH / g, and its active hydrogen equivalent is 130-150 g / mol.

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