Epoxy resin curing agent for corrosion prevention of stripping tower and preparation method of epoxy resin curing agent

Abstract

The invention discloses an epoxy resin curing agent for corrosion prevention of a stripping tower and a preparation method of the epoxy resin curing agent. The epoxy resin curing agent is prepared from 50-80% of sulfonyl chloride substances, 10-50% of polyamine substances and 10-50% of monofunctional glycidyl ether substances. According to the invention, polyamine is subjected to sulfonylation and epoxy addition two-step modification, and the preparation method has the following advantages: 1, stable sulfonyl is introduced, so that the product is not easy to hydrolyze under acidic and alkaline conditions, and the stability of a paint film is high; 2, after epoxy addition, the adhesive force of a product is good, and a paint film is not easy to blister and fall off; the paint film after two-step modification has excellent comprehensive properties such as humidity and heat resistance, acid and alkali resistance and the like, and can be suitable for complex working conditions of corrosion prevention of the stripping tower.

Description

Technical Field

[0001] The invention relates to an epoxy resin curing agent, in particular to an epoxy resin curing agent for stripping tower corrosion protection with high mechanical strength, good adhesion, good moisture and heat resistance and good acid and alkali resistance and a preparation method thereof, belonging to the technical field of polymer materials. Background Art

[0002] Metals will react chemically or electrochemically with the medium on their surface or in the surrounding environment, causing the metal to be damaged and lose its original properties. Metal corrosion is a very serious problem faced by people. The amount of metal materials scrapped due to corrosion each year is equivalent to more than 20% of the metal production in that year.

[0003] Stripping tower is a common equipment in the chemical industry. It is used to recover absorbed solutes and separate absorbents from solutes for regeneration. It is also used to remove light components in liquids. For example, steam is often used as a stripping agent in the oil refining industry to remove light components from oil products. Stripping towers have complex operating conditions and a wide variety of contact media. During use, there are multiple factors that affect fluid stress corrosion, acid-base chemical corrosion, biological corrosion, etc. Therefore, the anti-corrosion of stripping towers is a major issue facing factories.

[0004] Using coatings to protect metals is the simplest and most effective method. Among them, epoxy resin coatings are widely used in anti-corrosion coatings due to their excellent adhesion and excellent chemical resistance. Faced with the high requirements for stripping tower corrosion protection, it is difficult for ordinary epoxy anti-corrosion coatings to achieve long-term high-quality protection, mainly because the performance of epoxy curing agents is limited. Aromatic amine curing agents have excellent heat resistance, acid resistance, and salt spray resistance, but poor adhesion and water resistance. Polyamide curing agents have excellent adhesion, water resistance, and salt spray resistance, but their heat resistance and acid resistance are poor. Therefore, they cannot meet the anti-corrosion requirements of stripping towers.

[0005] The invention performs two-step modification of polyamine by sulfonylation and epoxy addition. First, the sulfonamide group generated after sulfonylation has high bond energy and is difficult to hydrolyze under acidic and alkaline conditions, and the product has good acid and alkali resistance. Then, epoxy addition modification is performed to give the product excellent adhesion and water resistance. After appropriate raw material selection, excellent comprehensive properties such as hardness, flexibility, adhesion, hot water resistance, acid resistance, alkali resistance, etc. can be obtained, and the product is suitable for stripping tower corrosion protection. Summary of the invention

[0006] Purpose of the invention: The purpose of the present invention is to provide an epoxy resin curing agent with high mechanical strength, good adhesion, moisture and heat resistance, and good acid and alkali resistance to meet the anti-corrosion requirements of the stripping tower; another purpose of the present invention is to provide a method for preparing the epoxy resin curing agent.

[0007] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0008] An epoxy resin curing agent for stripping tower corrosion protection is prepared from the following raw materials in percentage by mass: 50-80% of sulfonyl chloride substances, 10-50% of polyamine substances, and 10-50% of monofunctional glycidyl ether substances. HCl generated in the sulfonylation process is removed by water washing using an equimolar amount of triethylamine as an acid binding agent.

[0009] As a preferred embodiment, the epoxy resin curing agent for stripping tower corrosion protection described above, the sulfonyl chloride substance is one or a mixture of benzenesulfonyl chloride, p-toluenesulfonyl chloride, indane-5-sulfonyl chloride, pyrimidine-2-sulfonyl chloride, 2-phenyl-ethanesulfonyl chloride, 2-phenylmethylsulfonyl chloride, 1-ethylsulfonyl chloride, butanesulfonyl chloride, pentanesulfonyl chloride.

[0010] As a preferred embodiment, in the epoxy resin curing agent for stripping tower corrosion protection described above, the polyamine substance is one or a mixture of several of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, pentamethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, isophoronediamine, 1,3-cyclohexyldimethylamine, meta-xylylenediamine, cyclohexyldiamine, cyclopentamethylenediamine, diaminodicyclohexylmethane, and diaminodiphenylmethane.

[0011] As a preferred embodiment, the above-mentioned epoxy resin curing agent for stripping tower corrosion protection, the monofunctional glycidyl ether substance is one or a mixture of butyl glycidyl ether, C12-C14 alcohol glycidyl ether, C8-C10 alcohol glycidyl ether, butylphenyl glycidyl ether, cardanol glycidyl ether, phenyl glycidyl ether, o-cresol glycidyl ether, nonylphenol glycidyl ether, benzyl glycidyl ether.

[0012] The method for preparing the epoxy resin curing agent for stripping tower corrosion protection of the present invention comprises the following steps:

[0013] (1) Add the measured polyamines and triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.;

[0014] (2) adding the measured sulfonyl chloride substances into the reactor in batches, during which the temperature is controlled at 25-30° C.;

[0015] (3) After the sulfonyl chloride is added, the temperature is maintained at 25-30°C for 2 hours;

[0016] (4) Add measured water, continue stirring for 10 minutes, let stand and separate the layers, and remove the water layer;

[0017] (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor;

[0018] (6) After the water is removed, add the measured monofunctional glycidyl ether in batches, and control the temperature at 60-70°C;

[0019] (7) After the addition of glycidyl ether is completed, the temperature is maintained at 60-70° C. for 2 hours;

[0020] (8) After the heat-insulating reaction is completed, the mixture is cooled to below 40°C, filtered and discharged to obtain the finished product.

[0021] In the above preparation method, the HCl generated in the sulfonylation process is removed by washing with water using an equimolar amount of triethylamine as an acid-binding agent.

[0022] The present invention mainly improves the deficiencies of the prior art through the following solutions:

[0023] 1. The product of the present invention has a novel structure, and the polyamine is modified by two steps of sulfonylation and epoxy addition, showing excellent comprehensive performance.

[0024] 2. Sulfonamide bond energy is stronger than amide. Sulfonamide curing agent is not easy to hydrolyze under acidic or alkaline conditions, and the stability of the paint film is higher than that of amide epoxy curing agent.

[0025] 3. After epoxy addition, the adhesion of the product is improved, and the paint film is not easy to bubble and fall off.

[0026] 4. The present invention can achieve diversity in product molecular structure through raw material selection, thereby designing products suitable for different usage requirements.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0028] The present invention designs a novel epoxy curing agent, which performs two-step modification of polyamines by sulfonylation and epoxy addition, and has the following advantages: 1. The stable sulfonyl group is introduced, and the product is not easy to hydrolyze under acidic and alkaline conditions, and the paint film has high stability; 2. The product has good adhesion after epoxy addition, and the paint film is not easy to bubble and fall off. After the two-step modification, the paint film has excellent comprehensive properties such as moisture resistance, acid and alkali resistance, and can be applied to the complex working conditions of stripping tower corrosion protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The synthetic chemistry flow chart of the present invention is shown in FIG. DETAILED DESCRIPTION

[0030] Example 1

[0031] 1. An epoxy resin curing agent for stripping tower corrosion protection is made of the following raw materials in percentage by mass: 50% benzenesulfonyl chloride, 17% ethylenediamine, and 33% butyl glycidyl ether.

[0032] 2. A method for preparing an epoxy resin curing agent for stripping tower corrosion protection, comprising the following steps:

[0033] (1) Add 60 g of ethylenediamine and 101 g of triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.;

[0034] (2) adding 176 g of benzenesulfonyl chloride to the reactor of step (1) in batches, during which the temperature was controlled at 25-30° C.;

[0035] (3) After the benzenesulfonyl chloride is added, the temperature is maintained at 25-30°C for 2 hours;

[0036] (4) Add 100 g of water, continue stirring for 10 minutes, let stand to separate the layers, and remove the water layer;

[0037] (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor;

[0038] (6) After the water is removed, 116 g of butyl glycidyl ether is added in batches, and the temperature is controlled at 60-70°C;

[0040] (7) After the addition of butyl glycidyl ether is completed, the temperature is maintained at 60-70° C. for 2 hours;

[0041] (8) After the heat-insulating reaction is completed, the mixture is cooled to below 40°C, filtered and discharged to obtain the finished product.

[0042] Example 2

[0043] 1. An epoxy resin curing agent for stripping tower corrosion protection is made of the following raw materials in percentage by mass: 44% benzenesulfonyl chloride, 28% hexamethylenediamine, and 28% butyl glycidyl ether.

[0044] 2. A method for preparing an epoxy resin curing agent for stripping tower corrosion protection, comprising the following steps:

[0045] (1) Add 116 g of hexamethylenediamine and 101 g of triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.;

[0046] (2) adding 176 g of benzenesulfonyl chloride to the reactor of step (1) in batches, during which the temperature was controlled at 25-30° C.;

[0047] (3) After the benzenesulfonyl chloride is added, the temperature is maintained at 25-30°C for 2 hours;

[0048] (4) Add 100 g of water, continue stirring for 10 minutes, let stand to separate the layers, and remove the water layer;

[0049] (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor;

[0050] (6) After the water is removed, 116 g of butyl glycidyl ether is added in batches, and the temperature is controlled at 60-70°C;

[0052] (7) After the addition of butyl glycidyl ether is completed, the temperature is maintained at 60-70° C. for 2 hours;

[0053] (8) After the heat-insulating reaction is completed, the mixture is cooled to below 40°C, filtered and discharged to obtain the finished product.

[0054] Example 3

[0055] 1. An epoxy resin curing agent for stripping tower corrosion protection is made of the following raw materials in percentage by mass: 41% of benzenesulfonyl chloride, 27% of hexamethylenediamine, and 32% of phenyl glycidyl ether.

[0056] 2. A method for preparing an epoxy resin curing agent for stripping tower corrosion protection, comprising the following steps:

[0057] (1) Add 116 g of hexamethylenediamine and 101 g of triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.;

[0058] (2) 176 g of benzenesulfonyl chloride was added to the reactor in batches, and the temperature was controlled at 25-30° C.;

[0059] (3) After the benzenesulfonyl chloride is added, the temperature is maintained at 25-30°C for 2 hours;

[0060] (4) Add 100 g of water, continue stirring for 10 minutes, let stand to separate the layers, and remove the water layer;

[0061] (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor;

[0062] (6) After the water was removed, 136 g of phenyl glycidyl ether was added in batches, and the temperature was controlled at 60-70°C;

[0064] (7) After the addition of phenyl glycidyl ether is completed, the temperature is maintained at 60-70° C. for 2 hours;

[0065] (8) After the heat-insulating reaction is completed, the mixture is cooled to below 40°C, filtered and discharged to obtain the finished product.

[0066] Example 4 (Comparative Example 1)

[0067] 1. Example 2 removes the glycidyl ether modification step, that is, only sulfonylation modification is performed. It is made of the following raw materials in percentage by mass: 60% benzenesulfonyl chloride and 40% hexamethylenediamine.

[0068] 2. A method for preparing an epoxy resin curing agent for stripping tower corrosion protection, comprising the following steps:

[0069] (1) Add 116 g of hexamethylenediamine and 101 g of triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.;

[0070] (2) 176 g of benzenesulfonyl chloride was added to the reactor in batches, and the temperature was controlled at 25-30° C.;

[0071] (3) After the benzenesulfonyl chloride is added, the temperature is maintained at 25-30°C for 2 hours;

[0072] (4) Add 100 g of water, continue stirring for 10 minutes, let stand to separate the layers, and remove the water layer;

[0073] (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor;

[0074] (6) After the water is removed, the mixture is cooled to below 40°C, filtered and discharged to obtain the finished product.

[0075] Example 5 (Comparative Example 2)

[0076] 1. Example 2 removes the benzenesulfonyl chloride modification step, that is, only epoxy addition modification is performed. It is made of the following raw materials in percentage by mass: 50% hexamethylenediamine and 50% butyl glycidyl ether.

[0077] 2. A method for preparing an epoxy resin curing agent for stripping tower corrosion protection, comprising the following steps:

[0078] (1) 116 g of hexamethylenediamine was added into a reactor and the temperature was slowly raised to 60-70° C.;

[0079] (2) adding 116 g of butyl glycidyl ether in batches, during which the temperature was controlled at 60-70°C;

[0080] (3) After the addition of butyl glycidyl ether is completed, the temperature is maintained at 60-70° C. for 2 hours;

[0081] (4) After the heat-insulating reaction is completed, the mixture is cooled to below 40°C, filtered and discharged to obtain the finished product.

[0082] Example 6 (Comparative Example 3)

[0083] 1. In Example 2, benzenesulfonyl chloride is changed to benzoyl chloride, which is made from the following raw materials in percentage by mass:

[0084] 38% benzenesulfonyl chloride, 31% hexamethylenediamine, 31% butyl glycidyl ether.

[0085] 2. A method for preparing an epoxy resin curing agent for stripping tower corrosion protection, comprising the following steps:

[0086] (1) Add 116 g of hexamethylenediamine and 101 g of triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.;

[0087] (2) 140 g of benzoyl chloride was added to the above reactor in batches, and the temperature was controlled at 25-30° C.;

[0088] (3) After the benzoyl chloride is added, the temperature is maintained at 25-30°C for 2 hours;

[0089] (4) Add 100 g of water, continue stirring for 10 minutes, let stand to separate the layers, and remove the water layer;

[0090] (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor;

[0091] (6) After the water is removed, 116 g of butyl glycidyl ether is added in batches, and the temperature is controlled at 60-70°C;

[0093] (7) After the addition of butyl glycidyl ether is completed, the temperature is maintained at 60-70° C. for 2 hours;

[0094] (8) After the heat-insulating reaction is completed, the mixture is cooled to below 40°C, filtered and discharged to obtain the finished product.

[0095] Example 7 Performance Test

[0096] Epoxy resin (model 828 epoxy resin produced by Jiangsu Sanmu Chemical Co., Ltd., epoxy equivalent 185) was mixed evenly with the epoxy resin curing agent obtained in Examples 1-6 in proportion (mixing ratio = theoretical active hydrogen equivalent of curing agent / epoxy equivalent of epoxy resin*100%), and evenly coated on the tinplate to form a film with a film thickness of 40 μm. The basic properties of the obtained finished product after curing were measured as shown in the following table.

[0097]

[0098] The hardness test method adopts the pencil scratch method, which is based on the standard GB / T 6739-2006; the flexibility is determined by the mandrel bending method, which is based on the standard GB / T 1731-2020; the adhesion test adopts the pull-off method, which is based on the standard GB / T 5210-1985.

[0099] The above performance test results show that curing agents with different properties can be designed by selecting benzenesulfonyl chloride and polyamine. The comparison between Example 4 and Example 2 shows that epoxy addition modification can improve the flexibility and adhesion of the product; the comparison between Example 5, Example 6 and Example 2 shows that sulfonyl modification significantly improves the acid and alkali resistance of the product. In general, the epoxy resin curing agent product prepared by the two-step modification of sulfonylation and epoxy addition (Examples 1-3) has excellent hardness, flexibility and adhesion, as well as excellent resistance to moisture and heat, acid and alkali, and is suitable for the complex working conditions of the stripping tower anti-corrosion coating. In particular, the comprehensive performance of the raw materials in Example 3 is the best, and very good technical effects have been achieved.

[0100] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An epoxy resin curing agent for stripping tower corrosion protection, characterized in that: The invention is prepared from the following raw materials in the following mass percentages: 50-80% of sulfonyl chloride substances, 10-50% of polyamine substances and 10-50% of monofunctional glycidyl ether substances.

2. The epoxy resin curing agent for stripping tower anticorrosion according to claim 1, characterized in that The sulfonyl chloride substance is one or a mixture of benzenesulfonyl chloride, p-toluenesulfonyl chloride, indane-5-sulfonyl chloride, pyrimidine-2-sulfonyl chloride, 2-phenyl-ethanesulfonyl chloride, 2-phenylmethylsulfonyl chloride, 1-ethylsulfonyl chloride, butanesulfonyl chloride, and pentanesulfonyl chloride.

3. The epoxy resin curing agent for stripping tower anticorrosion according to claim 1, characterized in that The polyamine substance is one or a mixture of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, pentanediamine, hexanediamine, 2-methylpentanediamine, isophoronediamine, 1,3-cyclohexanedimethylamine, meta-xylylenediamine, cyclohexanediamine, cyclopentanediamine, diaminodicyclohexylmethane, and diaminodiphenylmethane.

4. The epoxy resin curing agent for stripping tower anticorrosion according to claim 1, characterized in that: The monofunctional glycidyl ether substance is one or a mixture of butyl glycidyl ether, C12-C14 alcohol glycidyl ether, C8-C10 alcohol glycidyl ether, butylphenyl glycidyl ether, cardanol glycidyl ether, phenyl glycidyl ether, o-cresol glycidyl ether, nonylphenol glycidyl ether and benzyl glycidyl ether.

5. The method for preparing the epoxy resin curing agent for stripping tower corrosion protection according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Add the measured polyamines and triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.; (2) adding the measured sulfonyl chloride substances into the reactor in batches, during which the temperature is controlled at 25-30° C.; (3) After the sulfonyl chloride is added, the temperature is maintained at 25 to 30° C. for 1 to 2 hours; (4) adding measured water, continuing stirring, allowing to stand for stratification, and removing the water layer by separation; (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor; (6) After the water is removed, add the measured monofunctional glycidyl ether in batches, and control the temperature at 60-70°C; (7) After the addition of glycidyl ether is completed, the temperature is maintained at 60-70° C. for 1-2 hours; (8) After the heat-insulating reaction is completed, the mixture is cooled, filtered, and discharged to obtain the finished product.

6. The method for preparing the epoxy resin curing agent for stripping tower anticorrosion according to claim 5, characterized in that: The following steps are involved: (1) Add the measured polyamines and triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.; (2) adding the measured sulfonyl chloride substances into the reactor in batches, during which the temperature is controlled at 25-30° C.; (3) After the sulfonyl chloride is added, the temperature is maintained at 25-30°C for 2 hours; (4) Add measured water, continue stirring for 10 minutes, let stand and separate the layers, and remove the water layer; (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor; (6) After the water is removed, add the measured monofunctional glycidyl ether in batches, and control the temperature at 60-70°C; (7) After the addition of glycidyl ether is completed, the temperature is maintained at 60-70° C. for 2 hours; (8) After the heat-insulating reaction is completed, the mixture is cooled to below 40°C, filtered and discharged to obtain the finished product.

7. A method for preparing an epoxy resin curing agent for stripping tower corrosion protection, characterized in that: The following steps are involved: (1) Add 116 g of hexamethylenediamine and 101 g of triethylamine into a reactor, stir to mix the materials evenly, and maintain the material temperature at 25-30° C.; (2) 176 g of benzenesulfonyl chloride was added to the reactor in batches, and the temperature was controlled at 25-30° C.; (3) After the benzenesulfonyl chloride is added, the temperature is maintained at 25-30°C for 2 hours; (4) Add 100 g of water, continue stirring for 10 minutes, let stand to separate the layers, and remove the water layer; (5) Turn on the vacuum and slowly raise the temperature to 60-70°C to remove a small amount of water in the reactor; (6) After the water was removed, 136 g of phenyl glycidyl ether was added in batches, and the temperature was controlled at 60-70°C; (7) After the addition of phenyl glycidyl ether is completed, the temperature is maintained at 60-70° C. for 2 hours; (8) After the heat-insulating reaction is completed, the mixture is cooled to below 40°C, filtered and discharged to obtain the product.

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