A curing accelerator for epoxy resins, a method of preparation, and coating compositions and applications containing the same

Abstract

The application provides a curing accelerator for epoxy resin, a preparation method, a coating composition containing the curing accelerator and application, the curing accelerator for epoxy resin has a general structure as shown in formula I; the method comprises the following steps: reacting alicyclic anhydride with a structure as shown in formula II and alcohol amine with a tertiary amine group and a structure as shown in formula III according to a certain proportion to obtain the curing accelerator for epoxy resin; the coating composition comprises A component and B component, the A component comprises liquid epoxy resin and epoxy active diluent; the B component comprises alicyclic diamine, the curing accelerator and an auxiliary agent; the application also provides a use of the coating composition for preparing a yellowing-resistant epoxy floor coating, specifically, the A component and the B component are mixed according to a mass ratio of 100:(30-35) and then cured to form.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of epoxy resin curing agent, in particular to a curing accelerator containing carboxyl, tertiary amine and alcohol hydroxyl at the same time and a preparation method thereof, and a coating composition prepared from the accelerator and application thereof. BACKGROUND

[0002] As one of the commonly used thermosetting resin systems, epoxy resin has a wide application in adhesive, coating, composite material and other fields due to the outstanding mechanical strength, bonding force, dielectric property, solvent resistance, heat resistance and low shrinkage of the cured product. Among them, the epoxy-amine system accounts for a high proportion in the entire epoxy resin field due to the convenient operation and flexible curing process.

[0003] In order to improve the curing speed of the epoxy-amine system and shorten the process time, an accelerator is usually added to the epoxy-amine formula system to improve the reaction degree. However, the accelerator for the epoxy-amine system has not been well developed since long-term development. Most of the commonly used epoxy-amine accelerators are phenols, carboxylic acids and tertiary amines, and the promoting effect of a single type of accelerator is limited. At the same time, the commonly used phenols (phenol, bisphenol A, o-cresol, etc.), carboxylic acids (salicylic acid, etc.) are solid at room temperature and need to be dissolved in solvents at high temperature for use, and the cured product produced by the accelerator is prone to red discoloration. The commonly used tertiary amines (DMP-10, DMP-30) have a strong smell and poor yellowing resistance. There is no technology for researching in this direction at home and abroad. SUMMARY

[0004] In order to solve the above problems of the accelerator in the epoxy-amine curing reaction process, the present application provides a novel accelerator containing carboxyl, tertiary amine and alcohol hydroxyl at the same time and a preparation method thereof, as well as a coating composition containing the accelerator and application thereof.

[0005] In order to achieve the purpose of the present application, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, the present application provides a curing accelerator for epoxy resin, which has a general structure as shown in Formula I:

[0007]

[0008] wherein R1 is selected from -H or C1-C3 alkyl, such as -H, methyl, ethyl, propyl, preferably -H and methyl;

[0009] R2 is selected from C1-C5 alkylene, such as -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2, preferably C2-C3 alkylene;

[0010] R3 is selected from C1-C4 alkyl groups, such as -CH3, -CH2CH3, -CH2CH2CH3, -CH2CH2CH2CH3, preferably C1-C3 alkyl groups;

[0011] R4 is selected from C1-C5 alkylene groups, such as -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, preferably C2-C3 alkylene groups.

[0012] In a second aspect, the present invention provides a method for preparing the above-mentioned curing accelerator for epoxy resin, comprising:

[0013] An alicyclic acid anhydride having the structure shown in Formula II is reacted with an alcoholic amine containing a tertiary amine group having the structure shown in Formula III in a certain proportion to obtain the curing accelerator for the epoxy resin.

[0014]

[0015] R1 is selected from -H or C1-C3 alkyl groups, such as -H, methyl, ethyl, propyl, preferably -H and methyl;

[0016] R2 is selected from C1-C5 alkylene groups, such as -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, preferably C2-C3 alkylene groups;

[0017] R3 is selected from C1-C4 alkyl groups, such as -CH3, -CH2CH3, -CH2CH2CH3, -CH2CH2CH2CH3, preferably C1-C3 alkyl groups;

[0018] R4 is selected from C1-C7 alkylene groups, such as -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, preferably C2-C3 alkylene groups.

[0019] In some specific embodiments, the molar ratio of the alicyclic anhydride to the alkanolamine containing the tertiary amine group is 1:(1.0 to 1.1), preferably 1:(1.0 to 1.05).

[0020] In some specific embodiments, under stirring conditions, alicyclic anhydrides are slowly added dropwise to an alcohol amine containing a tertiary amine group. This stirring is preferably carried out at a speed of 200 r / min to 500 r / min, more preferably at 250 r / min to 350 r / min, for example, 280 r / min, 300 r / min, or 320 r / min.

[0021] In some specific embodiments, the above reaction is carried out at 80°C to 120°C, preferably 90°C to 110°C, for example, 95°C, 100°C, or 105°C. Specifically, the reaction time is 2 to 4 hours, preferably 3 to 4 hours.

[0022] In some preferred embodiments, the reaction is carried out under the protection of an inert gas, selected from nitrogen or argon, preferably in a nitrogen atmosphere.

[0023] In a third aspect, the present invention provides a coating composition for a yellowing-resistant floor coating, the coating composition comprising component A and component B, wherein component A comprises a liquid epoxy resin and an epoxy reactive diluent; and component B comprises an alicyclic diamine, a curing accelerator, and additives, wherein the additives include a dispersant and a defoamer.

[0024] The curing accelerator is the epoxy resin curing accelerator described above or the epoxy resin curing accelerator prepared by the above method.

[0025] In some specific embodiments, based on the mass fractions of each component in component A (total mass fractions are 100), component A includes:

[0026] 85-100 parts of liquid epoxy resin, preferably 90-95 parts;

[0027] 0-15 parts of epoxy reactive diluent, preferably 5-10 parts;

[0028] Based on the mass fractions of each component in component B (total mass fractions are 100), component B includes:

[0029] 60-80 parts of alicyclic diamine, preferably 64-79 parts;

[0030] 5-35 parts of benzyl alcohol, preferably 9-28 parts;

[0031] 5 to 15 parts of epoxy resin curing accelerator, preferably 8 to 12 parts;

[0032] The dispersant is used in an amount of 0.1 to 1 part, preferably 0.2 to 0.6 parts;

[0033] The defoamer is 0.2 to 2 parts, preferably 0.4 to 0.7 parts.

[0034] In some specific embodiments, the preparation method of component A is as follows: mixing liquid epoxy resin and epoxy reactive diluent to obtain component A;

[0035] The preparation method of component B is as follows: alicyclic diamine, benzyl alcohol, and epoxy resin are mixed with curing accelerator, dispersant and defoamer to obtain component B.

[0036] In some specific embodiments, the liquid epoxy resin is selected from bisphenol A type epoxy resin, preferably type 128 epoxy resin.

[0037] The epoxy reactive diluent is selected from phenyl glycidyl ether, toluene-based glycidyl ether, benzyl glycidyl ether, and C. 12 -C 14 One or more of glycidyl ether or butyl glycidyl ether;

[0038] The alicyclic diamine is selected from one or more of diaminodicyclohexylmethane, isophorone diamine, 1,3-cyclohexanedimethylamine, or 1,2-cyclohexanediamine; in some preferred embodiments, it is diaminodicyclohexylmethane and / or isophorone diamine;

[0039] The dispersant is selected from one or more of fatty acid derivative dispersants, aliphatic amide dispersants, and ester dispersants, preferably fatty acid dispersants, such as Tego Dispers 610 and / or Dispers 630.

[0040] The defoamer is selected from one or more of polyether defoamers, silicone defoamers, and alcohol defoamers; preferably silicone defoamers, such as BYK066N and / or BYKA530.

[0041] In a fourth aspect, the present invention also provides a method for preparing a yellowing-resistant epoxy floor coating from the above-mentioned coating composition, wherein component A and component B are mixed in a mass ratio of 100:(30-35) and then cured to form the coating.

[0042] In some specific implementations, component A and component B are mixed in a mass ratio of 100:(31-33), for example, 100:32.

[0043] The above technical solution achieves the following technical effects:

[0044] Compared to traditional carboxylic acid (salicylic acid) and phenolic accelerators (phenol, bisphenol A, etc.), the epoxy resin curing accelerator provided by this invention contains carboxylic acid groups, tertiary amine groups and hydroxyl groups, which have higher accelerating effect and yellowing resistance. At the same time, the accelerator provided by this invention is a colorless liquid at room temperature, which makes it more convenient to use and easier to mix into the formulation system.

[0045] The yellowing-resistant epoxy floor coating provided by this invention has a faster curing speed, lower odor, and superior yellowing resistance. Attached Figure Description

[0046] Figure 1 Infrared spectrum of the epoxy resin curing accelerator obtained in the embodiments of the present invention. Detailed Implementation

[0047] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0048] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0049] The following implementation methods were tested using the following methods:

[0050] (1) Curing agent color: Colorimetric tests were performed using a Shimadzu UV-1201V spectrophotometer;

[0051] (2) Hardener viscosity: Tested using Brookfield DV2T viscometer under the following conditions: 25°C, rotor No. 28.

[0052] (3) Operation time: The time for 100g of AB mixture to form threads at 25℃;

[0053] (4) Surface drying time: the time it takes for a 3mm thick paint film to become non-sticky at 25℃;

[0054] (5) Hardness of cured product: The hardness data obtained by using a Shore D hardness tester after 10g of AB mixture reacted in a disposable plastic cup at 25℃ for 24h.

[0055] (6) Yellowing resistance test: After the 3mm thick paint film has been cured for 7 days, the color of the paint film is observed after being irradiated under a 60W ultraviolet lamp for 1 hour.

[0056] Raw material source:

[0057]

[0058] Example 1

[0059] Add 119g of N-methyldiethanolamine to a 500ml three-necked flask, purge the flask with nitrogen and start mechanical stirring. Heat the material to 90℃ using an oil bath while stirring at 250r / min. Then weigh 168g of methylhexahydrophthalic anhydride and slowly add it dropwise to the three-necked flask. After reacting for 3 hours, the epoxy resin curing accelerator AC-1 containing carboxylic acid groups, tertiary amine groups and alcohol hydroxyl groups is obtained as shown in the following formula.

[0060]

[0061] The accelerator AC-1 obtained by the above method was subjected to infrared analysis, and the analysis results are attached. Figure 1 As shown; it can be seen from this spectrum that 1820cm -1 The absorption peaks of acid anhydrides C=O and 1300–1200 cm⁻¹ are located at the following locations. -1 The disappearance of the COC stretching vibration absorption peak at 3300-2500 cm⁻¹, and the disappearance of the absorption peak at 3300-2500 cm⁻¹. -1 The appearance of the absorption peak of the -OH stretching vibration of the carboxylic acid association indicates that N-methyldiethanolamine reacts with methylhexahydrophthalic anhydride in the system, and that the reaction of methylhexahydrophthalic anhydride is complete.

[0062] Example 2

[0063] Add 139.65g of N-ethyldiethanolamine to a 500ml three-necked flask, purge the flask with nitrogen and start mechanical stirring. Heat the material to 110℃ using an oil bath while stirring at 350r / min. Then weigh 154g of 1,2-cyclohexanedicarboxylic anhydride and slowly add it dropwise to the three-necked flask. After reacting for 4 hours, the epoxy resin curing accelerator AC-2 containing carboxylic acid groups, tertiary amine groups and alcohol hydroxyl groups is obtained as shown in the following formula.

[0064]

[0065] The accelerator AC-2 obtained by the above method was subjected to infrared analysis, and its spectrum was similar to that of Example 1.

[0066] Example 3

[0067] Add 75.7g of N-propyldiethanolamine and 75.7g of 3-(3-hydroxypropylamino)-1-propanol to a 500ml three-necked flask. Purge the flask with nitrogen and start mechanical stirring. Heat the material to 110℃ using an oil bath while stirring at 350r / min. Then weigh 154g of 1,2-cyclohexanedicarboxylic anhydride and slowly add it dropwise to the three-necked flask. After reacting for 4 hours, the epoxy resin curing accelerator AC-3 containing carboxylic acid groups, tertiary amine groups, and alcohol hydroxyl groups is obtained as shown in the following formula.

[0068]

[0069] The accelerator AC-3 obtained by the above method was subjected to infrared analysis, and its spectrum was similar to that of Example 1.

[0070] Example 4

[0071] Add 147g of 3-[(2-hydroxyethyl)methylamino]-1-propanol to a 500ml three-necked flask, purge the flask with nitrogen and start mechanical stirring. Heat the material to 100℃ using an oil bath while stirring at 320r / min. Then weigh 84g of methylhexahydrophthalic anhydride and 77g of 1,2-cyclohexanedicarboxylic anhydride and heat them to 50℃ to melt them into liquid. Slowly add the liquid dropwise to the three-necked flask. After reacting for 3.8h, the epoxy resin curing accelerator AC-4 containing carboxylic acid groups, tertiary amine groups and alcohol hydroxyl groups, as shown in the following formula, can be obtained.

[0072]

[0073] The accelerator AC-4 obtained by the above method was subjected to infrared analysis, and its spectrum was similar to that of Example 1.

[0074] Example 5

[0075] In a 500ml three-necked flask, 59.5g of N-methyldiethanolamine and 66.5g of N-ethyldiethanolamine were placed. Nitrogen gas was introduced into the flask and mechanical stirring was started. The materials were heated to 95℃ using an oil bath while stirring at 305r / min. Then, 84g of methylhexahydrophthalic anhydride and 77g of 1,2-cyclohexanedicarboxylic anhydride were weighed and heated to 50℃ to melt into liquid. The liquid was then slowly added dropwise to the three-necked flask. After reacting for 3.8h, an epoxy resin curing accelerator AC-5 containing carboxylic acid groups, tertiary amine groups, and alcohol hydroxyl groups was obtained as shown in the following formula.

[0076]

[0077] The accelerator AC-5 obtained by the above method was subjected to infrared analysis, and its spectrum was similar to that of Example 1.

[0078] The basic properties of the epoxy resin curing accelerators obtained above were tested compared with those of conventional accelerators salicylic acid, bisphenol A, and DMP-30. The test data are shown in Table 1 below.

[0079] Table 1

[0080]

[0081] As can be seen from the data in Table 1 above, compared with salicylic acid and bisphenol A solid accelerators, the accelerators AC-1 to AC-5 obtained in the embodiments of the present invention are low-viscosity liquids at room temperature, which has better handling convenience. Furthermore, compared with the currently commonly used DMP-30 accelerator, the accelerators obtained in the present invention have lower odor, lower viscosity, and better color.

[0082] The above-mentioned epoxy resin was used to prepare a coating composition according to the following formula ratio, as shown in the table below:

[0083] Component A contains:

[0084] Composition Mass parts NPEL 128 liquid epoxy resin 93 C 12 -C 14 glycidyl ethers 7

[0085] Component B contains:

[0086] Composition Mass parts Diamino dicyclohexyl methane 79 Benzyl alcohol 12 Curing accelerator for epoxy resins 8 Tego Dispers 610 dispersant 0.5 BYK 066 N defoamer 0.5

[0087] By using different types of accelerators, the materials in components A and B are mixed at room temperature according to the above-mentioned proportions. After uniform mixing, component A and component B containing different accelerators are obtained.

[0088] After mixing in a mass ratio of 100:32 and curing, a yellowing-resistant epoxy floor coating is obtained.

[0089] The performance of the B component containing different accelerators and the resulting epoxy floor coating were tested, and the test data are shown in Tables 2 and 3 below:

[0090] Table 2

[0091]

[0092]

[0093] Table 3

[0094]

[0095] As can be seen from the comparative data in Tables 2 and 3, compared with commonly used accelerators (salicylic acid, bisphenol A, DMP-30, etc.), the curing agent prepared by the accelerator containing carboxylic acid groups, tertiary amine groups and alcohol hydroxyl groups provided by the present invention has a shorter operating time and surface drying time, higher hardness and better resistance to yellowing; at the same time, the accelerator provided by the present invention is a colorless and odorless liquid at room temperature, which makes it more convenient to operate and has better resistance to yellowing.

Claims

1. A curing accelerator for epoxy resins, characterized by, The curing accelerator for epoxy resin has a general structure as shown in Formula I: Formula I R1 is selected from -H or C1-C3 alkyl; R2 is selected from C1-C5 alkylene; R3 is selected from C1-C4 alkyl; R4 is selected from C1-C5 alkylene.

2. The curing accelerator for epoxy resins according to claim 1, characterized by In the general structure shown in Formula I, R1 is selected from -H or methyl.

3. The curing accelerator for epoxy resins according to claim 1, characterized by In the general structure shown in Formula I, R2 is selected from C2-C3 alkylene.

4. The curing accelerator for epoxy resins according to claim 1, characterized by In the general structure shown in Formula I, R3 is selected from C1-C3 alkyl.

5. The curing accelerator for epoxy resins according to claim 1, characterized by In the general structure shown in Formula I, R4 is selected from C2-C3 alkylene.

6. A method for producing the curing accelerator for epoxy resins according to claim 1, characterized by, The method comprises: reacting a cycloaliphatic anhydride having a structure shown in Formula II with a tertiary amine group-containing alcohol amine having a structure shown in Formula III at a molar ratio of 1: (1.0-1.1) to obtain the curing accelerator for epoxy resin; Formula II Formula III R1 is selected from -H or C1-C3 alkyl; R2 is selected from C1-C5 alkylene; R3 is selected from C1-C4 alkyl; R4 is selected from C1-C5 alkylene.

7. The method of claim 6, wherein, In the structure shown in Formula II, R1 is selected from -H or methyl.

8. The method of claim 6, wherein, In the structure shown in Formula III, R2 is selected from C2-C3 alkylene.

9. The method of claim 6, wherein, In the structure shown in Formula III, R3 is selected from C1-C3 alkyl.

10. The method of claim 6, wherein, In the structure shown in Formula III, R4 is selected from C2-C3 alkylene.

11. The method of claim 6, wherein, The molar ratio of the cycloaliphatic anhydride to the tertiary amine group-containing alcohol amine is 1: (1.0-1.05).

12. The method of claim 11, wherein, The cycloaliphatic anhydride is slowly added dropwise into the tertiary amine group-containing alcohol amine under stirring.

13. The method of claim 12, wherein, The stirring is performed at a speed of 200 r / min-500 r / min.

14. The method of claim 13, wherein, The stirring is performed at a speed of 250 r / min-350 r / min.

15. The method according to any one of claims 6-14, characterized in that, The reaction is performed at 80℃-120℃; The reaction time is 2-4 h.

16. The method of claim 15, wherein, The reaction is performed at 90℃-110℃.

17. The method of claim 15, wherein, The reaction time is 3-4 h.

18. The method of claim 15, wherein, The reaction is performed under protection of an inert gas selected from nitrogen, argon.

19. The method of claim 18, wherein, The inert gas is nitrogen.

20. A coating composition characterized in that, The coating composition comprises an A component and a B component, the A component comprises a liquid epoxy resin and an epoxy reactive diluent; the B component comprises a cycloaliphatic diamine, a curing accelerator, benzyl alcohol and an auxiliary agent, wherein the auxiliary agent comprises a dispersant and a defoaming agent; The curing accelerator is the curing accelerator for epoxy resin according to claim 1 or the curing accelerator for epoxy resin prepared by the method according to any one of claims 6-19.

21. The coating composition of claim 20, wherein, In the A component, in mass fraction: liquid epoxy resin 85-100 parts; epoxy reactive diluent 5-15 parts; In the B component, in mass fraction: cycloaliphatic diamine 60-80 parts; benzyl alcohol 5-35 parts; curing accelerator for epoxy resin 5-15 parts; dispersant 0.1-1 part; defoaming agent 0.2-2 parts.

22. The coating composition of claim 21, wherein, In the A component, in mass fraction: liquid epoxy resin 90-95 parts; epoxy reactive diluent 5-10 parts; In the B component, in mass fraction: cycloaliphatic diamine 64-79 parts; benzyl alcohol 9-28 parts; curing accelerator for epoxy resin 8-12 parts; 0.2-0.6 parts of dispersing agent; 0.4-0.7 parts of defoaming agent.

23. The coating composition of claim 21, wherein, The preparation method of the A component is mixing liquid epoxy resin and epoxy active diluent to obtain the A component; The preparation method of the B component is mixing alicyclic diamine, benzyl alcohol, epoxy resin with curing accelerator, dispersing agent and defoaming agent to obtain the B component.

24. The coating composition according to any one of claims 21-23, characterized in that, The liquid epoxy resin is selected from bisphenol A type epoxy resin; The epoxy reactive diluents are selected from the group consisting of phenyl glycidyl ether, o-cresyl glycidyl ether, benzyl glycidyl ether, C 12 -C 14 one or more of a glycidyl ether or a butyl glycidyl ether; The alicyclic diamine is selected from one or more of diamino dicyclohexyl methane, isophorone diamine, 1,3-cyclohexane dimethylamine or 1,2-cyclohexane diamine; The dispersing agent is selected from one or more of fatty acid derivatives, aliphatic amides and esters; The defoaming agent is selected from one or more of polyether, silicone and alcohol.

25. The coating composition of claim 24, wherein, The liquid epoxy resin is selected from 128 type epoxy resin.

26. The coating composition of claim 24, wherein, The alicyclic diamine is diamino dicyclohexyl methane and / or isophorone diamine.

27. The coating composition of claim 24, wherein, The dispersing agent is selected from fatty acid derivatives.

28. The coating composition of claim 24, wherein, The defoaming agent is selected from silicone defoaming agent.

29. Use of the coating composition according to any one of claims 20 to 28 for the preparation of a yellowing-resistant epoxy floor finish, characterized in that, The A component and the B component are mixed in a mass ratio of 100: (30-35) to form the yellowing-resistant epoxy floor coating after curing.

30. Use according to claim 29, characterized in that, The A component and the B component are mixed in a mass ratio of 100: (31-33).

Images