Cardanol mercaptomaleic acid and preparation method thereof, cardanol-based toughened vinyl photocurable resin and preparation method and application thereof

Abstract

The present invention belongs to the technical field of polymer materials and specifically relates to a cardanol mercaptomaleic acid and its preparation method, a cardanol-based toughened vinyl photocurable resin, and its preparation method and application. The present invention first synthesizes a difunctional cardanol mercaptomaleic acid as a chain extender, then reacts an epoxy resin and an olefinically unsaturated monocarboxylic acid to perform semi-end-capping, then uses the cardanol mercaptomaleic acid for chain extension, and finally adds a reactive diluent for dilution to obtain a cardanol-based toughened vinyl photocurable resin. The present invention introduces a long carbon chain cardanol mercaptomaleic acid into an epoxy resin containing a large number of benzene ring structures, which can effectively improve the tensile strength and toughness of the cured film. The glass transition temperature of the cured film can be regularly adjusted, the storage stability is good, the crosslinking density is high, and the curing method is efficient, convenient, and environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular relates to a cardanol mercaptomaleic acid and a preparation method thereof, a cardanol-based toughened vinyl photocurable resin and a preparation method and application thereof. Background Art

[0002] Epoxy resins are formed by the reaction of epoxy groups with compounds containing multifunctional groups. By forming a three-dimensional network structure, they impart high strength, high modulus, and excellent heat resistance to the material. As an important polymer material, epoxy resins are widely used in various industrial fields due to their excellent mechanical properties, chemical resistance, good electrical insulation, and adhesion. However, the performance of traditional epoxy resins in certain applications, such as those requiring high toughness, rapid curing, or special environments (such as antibacterial and corrosion resistance), still needs to be improved.

[0003] Vinyl ester resins are typically produced by the ring-opening addition reaction of epoxy resins and monounsaturated carboxylic acids, followed by dissolution in an unsaturated reactive monomer. Structurally, because the double bonds involved in free radical curing are located at the ends of the molecular chain, they exhibit high curing activity and are easily moldable. Furthermore, the commonly used epoxy resins have a bisphenol A structure, with a large number of rigid benzene rings in the main chain, resulting in high tensile strength in the cured films.

[0004] Currently, the chain extenders commonly used for vinyl ester resins are mostly difunctional, and the final resin obtained has a linear structure. This type of resin has low curing activity, easily sticky surface, and poor mechanical properties, so it needs to be modified. Summary of the Invention

[0005] According to a first aspect of the present invention, there is provided a cardanol mercaptomaleic acid having the structural formula:

[0006]

[0007] According to a second aspect of the present invention, there is provided a method for preparing the above-mentioned cardanol mercaptomaleic acid, comprising the following steps:

[0008] Cardanol is subjected to a photo-click reaction with mercaptoethanol to obtain cardanol mercapto alcohol; and cardanol mercapto alcohol is subjected to an esterification reaction with maleic anhydride to obtain cardanol mercaptomaleic acid.

[0009] The present invention utilizes cardanol, which contains a benzene ring, a phenol structure, and long side chain aliphatic groups. The phenol structure can complex with metal ions, thereby exerting an antibacterial effect. Its side chain double bonds can be modified through a photoclick reaction, introducing new functional groups (hydroxyl groups), which can then be further esterified to obtain a carboxylic acid structure. The carboxylic acid structure can participate in the ring opening of the epoxy, thus allowing chain extension modification of epoxy resins. Furthermore, the long side chain aliphatic groups of cardanol can increase the toughness of vinyl resins.

[0010] In some embodiments, the preparation method of cardanol mercaptomaleic acid comprises the following steps:

[0011] In parts by mass, 140-160 parts of cardanol, 80-90 parts of mercaptoethanol, and 5-10 parts of photoinitiator are reacted under ultraviolet light for 3-7 hours to obtain cardanol mercapto alcohol; then 50-70 parts of cardanol mercapto alcohol and 80-90 parts of maleic anhydride are reacted at 50-120°C for 18-30 hours to obtain cardanol mercaptomaleic acid.

[0012] In some embodiments, the photoinitiator is ITX photoinitiator (2-isopropylthioxanthone), 1173 photoinitiator (2-hydroxy-2-methyl-1-phenyl-1-propanone), or TPO photoinitiator (diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide).

[0013] According to a third aspect of the present invention, there is provided a cardanol-based toughened vinyl photocurable resin, the raw material composition of which comprises, in parts by mass: 120-160 parts of epoxy resin, 0.9-1.4 parts of catalyst, 0.03-0.06 parts of polymerization inhibitor, 45-63 parts of monounsaturated carboxylic acid containing olefinic bond, 2-56 parts of cardanol mercaptomaleic acid, and 55-75 parts of reactive diluent.

[0014] In some embodiments, the epoxy resin is at least one of bisphenol A epoxy resin, bisphenol AD ​​epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin.

[0015] In some embodiments, the catalyst is at least one of benzyltriethylammonium chloride, dibutyltin dilaurate, triethylamine, and triphenylphosphine.

[0016] In some embodiments, the polymerization inhibitor is at least one of hydroquinone, p-tert-butylcatechol, and catechol.

[0017] In some embodiments, the ethylenically unsaturated monocarboxylic acid is at least one of acrylic acid, methacrylic acid, crotonic acid, and phenylacrylic acid.

[0018] In some embodiments, the reactive diluent is at least one of styrene, α-methylstyrene, methyl acrylate, isobornyl acrylate, tripropylene glycol diacrylate, and trimethylolpropane triacrylate.

[0019] According to a fourth aspect of the present invention, there is provided a method for preparing the above-mentioned cardanol-based toughened vinyl photocurable resin, comprising the following steps:

[0020] The epoxy resin is reacted with a monounsaturated carboxylic acid containing an olefinic bond under the action of a catalyst and a polymerization inhibitor, and then the remaining epoxy groups are completely reacted with cardanol mercaptomaleic acid. Finally, an active diluent is added and mixed evenly to obtain the product.

[0021] The present invention utilizes the cardanol mercaptomaleic acid obtained by modifying cardanol with mercaptoethanol and maleic anhydride to carry out chain extension modification on epoxy resin to obtain a modified vinyl ester resin, which is then cured by double-bond free radicals to obtain a cardanol-based toughened vinyl light-cured resin. Specifically, a difunctional cardanol mercaptomaleic acid is first synthesized as a chain extender, and then the epoxy resin and the monobasic unsaturated carboxylic acid containing an olefinic bond are reacted to perform half-end blocking, and then the cardanol mercaptomaleic acid is used for chain extension, and finally a reactive diluent is added to dilute the cardanol-based toughened vinyl light-cured resin. The present invention introduces the cardanol mercaptomaleic acid containing a long carbon chain into the epoxy resin containing a large number of benzene ring structures, which can effectively improve the tensile strength and toughness of the cured film, the glass transition temperature of the cured film can be regularly adjusted, the storage stability is good, the cross-linking density is high, and the curing method is efficient, convenient, and green.

[0022] In some embodiments, the preparation method of the cardanol-based toughened vinyl photocurable resin comprises the following steps:

[0023] The epoxy resin, catalyst, polymerization inhibitor, and olefinic monounsaturated carboxylic acid are reacted at 85-110° C. for 2-5 hours until the acid value is less than 30 mg KOH / g. Then, cardanol mercaptomaleic acid is added and the reaction is continued at 85-110° C. for 2-5 hours until the acid value is less than 30 mg KOH / g. The reaction is then cooled to below 80° C., and a reactive diluent is added and mixed uniformly to obtain the product.

[0024] According to a fifth aspect of the present invention, there is provided a use of the above-mentioned cardanol-based toughened vinyl photocurable resin in the preparation of 3D printing materials, UV coatings, adhesives, packaging materials or anti-corrosion coatings.

[0025] The beneficial effects of the present invention include:

[0026] (1) The present invention introduces a cardanol-based toughening agent cardanol mercapto maleic acid containing a long carbon chain into a petroleum-based epoxy resin, and combines the petroleum-based epoxy resin with high hardness and poor toughness with the cardanol mercapto maleic acid with good toughness and low hardness through the ring-opening reaction of epoxy and carboxylic acid. The cardanol mercapto maleic acid has a difunctional structure, which can increase the cross-linking density of the resin, thereby allowing the resin to maintain a high hardness while increasing toughness. With the different amounts of cardanol mercapto maleic acid used, the glass transition temperature of the obtained cured film shows regular changes, thereby the glass transition temperature of the cured film can be regularly regulated. The cardanol-based toughened vinyl photocurable resin prepared by the present invention has a uniform appearance without stratification and a low viscosity, and is suitable for preparing 3D printing materials, UV coatings, adhesives, packaging materials or anti-corrosion coatings.

[0027] (2) The present invention combines cardanol with a vinyl resin and utilizes light-curing technology to achieve rapid curing, thereby producing a novel resin material having excellent toughness, antibacterial properties, corrosion resistance, and rapid curing capability. The cardanol-based toughened vinyl light-curing resin of the present invention not only effectively improves the mechanical properties, antibacterial properties, and corrosion resistance of the cured film, but also fully utilizes the advantages of light-curing technology such as rapidity, energy saving, and controllability, providing the industry with a high-performance, environmentally friendly new material solution. At the same time, the introduction of cardanol also helps to reduce the cost of the resin and improve its competitiveness in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the reaction scheme of step (1) of Example 1 of the present invention.

[0029] Figure 2 This is the reaction scheme of step (2) of Example 1 of the present invention.

[0030] Figure 3 This is the reaction scheme of step (3) of Example 1 of the present invention.

[0031] Figure 4 It is the Fourier transform infrared spectrum of cardanol, cardanol mercapto alcohol and cardanol mercaptomaleic acid in Example 1 of the present invention.

[0032] Figure 5 It is a Fourier transform infrared spectrum of the epoxy resin and cardanol-based toughened vinyl photocurable resin of Example 1 of the present invention.

[0033] Figure 6 1 and 2 are electrochemical impedance spectroscopy diagrams of the resin coatings of Comparative Example 1, Example 1, Example 3, and Example 5. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto. The materials involved in the following examples can all be obtained from commercial channels.

[0035] Example 1

[0036] The preparation method of the cardanol-based toughened vinyl light-curing resin of this embodiment comprises the following steps:

[0037] (1) Add 150.0g of cardanol, 85.9g of mercaptoethanol, and 7.1g of 1173 photoinitiator to a 500mL round-bottom flask, stir magnetically, and irradiate under 365nm ultraviolet light for about 5h. The reaction endpoint is reached when the double bond peak disappears completely by infrared observation. Then add 300g of dichloromethane to the round-bottom flask to dissolve it, transfer the solution to a separatory funnel, and wash with deionized water until the water layer is no longer turbid. Finally, the organic phase is evaporated at 45°C to remove the solvent to obtain light yellow transparent cardanol mercapto alcohol. The reaction scheme of this step is as follows: Figure 1 shown.

[0038] (2) Add 60.0g of the cardanol mercapto alcohol obtained in step (1) and 82.4g of maleic anhydride into a 500mL three-necked flask, stir magnetically, and heat to 80°C in a nitrogen environment for 24h. The reaction product is tested by infrared and the carboxyl peak appears, indicating that the reaction has reached the end point. Ethyl acetate is added to the obtained reaction product to dissolve it, and it is washed with deionized water. Then, the ethyl acetate is removed by rotary evaporation at 50°C to obtain dark yellow transparent cardanol mercaptomaleic acid. The reaction route of this step is as follows: Figure 2 shown.

[0039] (3) In a 500 mL round-bottom flask, 145.28 g of bisphenol A epoxy resin E-44 (molecular weight 454), 59.38 g of acrylic acid, 0.0418 g of inhibitor hydroquinone, and 1.0462 g of catalyst benzyltriethylammonium chloride were added, and the temperature was raised to 90° C. to react for about 3.5 hours until the acid value was less than 30 mgKOH / g. Then 4.58 g of cardanol mercaptomaleic acid prepared in step (2) was added, and the mixture was reacted at 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. Then the mixture was cooled to below 80° C., 62.77 g of styrene was added, and the mixture was mixed evenly to obtain a light yellow transparent cardanol-based toughened vinyl photocurable resin. The reaction scheme of this step is as follows: Figure 3 shown.

[0040] The Fourier transform infrared spectra of cardanol, cardanol mercapto alcohol and cardanol mercaptomaleic acid in this embodiment are as follows: Figure 4 As shown, the Fourier transform infrared spectra of epoxy resin and cardanol-based toughened vinyl photocurable resin are as follows Figure 5 shown.

[0041] from Figure 4 By comparison, it can be seen that the raw material is cardanol (denoted as CA), the product of step (1) is cardanol mercapto alcohol (denoted as CAM), and the product of step (2) is cardanol mercaptomaleic acid (denoted as CAMM). Specifically:

[0042] In the FTIR spectrum of CA, 3010 cm -1 Corresponding to the CH characteristic stretching vibration of C=CH on the side chain; 2928cm -1 and 2855cm -1 Corresponding to the asymmetric stretching of methylene and methyl groups in long aliphatic chains; and 3600cm -1 to 3300cm -1 The long peak is the OH stretching vibration on the benzene ring, that is, the characteristic peak of phenol-OH. When CA reacts with mercaptoethanol through photo-click reaction, 3010cm -1 The peak of 1050cm-1 disappeared, indicating that mercaptoethanol had completely reacted with the double bond of the cardanol side chain. -1 The peak at 1724 cm corresponds to the alcoholic hydroxyl group, indicating that CAM has been successfully synthesized. -1 A new signal peak appears, which is the carbonyl stretching vibration of the ester group, 1220 cm -1 and 1404cm -1 The two new peaks at 400 nm are the stretching vibrations of the ester bond CO, indicating that maleic anhydride and CAM are successfully grafted together. Therefore, the FT-IR results show that the product of step (2) is CAMM.

[0043] from Figure 5 By comparison, it can be seen that the raw material is epoxy resin (denoted as E44) and the product is cardanol-based toughened vinyl light-curing resin (denoted as VER).

[0044] Seen in E44 at 915cm -1 The characteristic peak appearing near is the epoxy vibration peak, 1607cm -1 is the stretching vibration of C=C on the benzene ring, 831cm -1 It is the absorption peak of the opposite substitution vibration on the benzene ring. When E44 undergoes a series of ring-opening and end-capping reactions, 915cm -1 The characteristic peak of epoxy disappears, indicating that the epoxy group reacts with the carboxylic acid to complete the ring opening. -1 The peaks are the stretching vibrations of C=O on the unsaturated monocarboxylic acid ester bond. Therefore, the FT-IR results show that the product is a cardanol-based toughened vinyl photocurable resin.

[0045] Example 2

[0046] The preparation method of the cardanol-based toughened vinyl light-curing resin of this embodiment comprises the following steps:

[0047] (1) 150.0 g of cardanol, 85.9 g of mercaptoethanol, and 7.1 g of 1173 photoinitiator were added to a 500 mL round-bottom flask, magnetically stirred, and irradiated under 365 nm ultraviolet light for about 5 h. The reaction endpoint was reached when the double bond peak disappeared completely by infrared observation. 300 g of dichloromethane was then added to the round-bottom flask to dissolve the solution. The solution was transferred to a separatory funnel and washed with deionized water until the water layer was no longer turbid. Finally, the organic phase was rotary evaporated at 45 ° C to remove the solvent to obtain light yellow transparent cardanol mercapto alcohol.

[0048] (2) In a 500 mL three-necked flask, 60.0 g of the cardanol mercapto alcohol obtained in step (1) and 82.4 g of maleic anhydride were added. The mixture was stirred magnetically and heated to 80° C. in a nitrogen atmosphere for 24 h. The reaction product was tested by infrared spectroscopy. The reaction endpoint was reached when a carboxyl peak appeared. Ethyl acetate was added to the obtained reaction product to dissolve it, and the product was washed with deionized water. The ethyl acetate was then removed by rotary evaporation at 50° C. to obtain dark yellow, transparent cardanol mercaptomaleic acid.

[0049] (3) In a 500 mL round-bottom flask, 145.28 g of bisphenol A epoxy resin E-44 (molecular weight 454), 56.49 g of acrylic acid, 0.0436 g of hydroquinone (a polymerization inhibitor), and 1.0890 g of benzyltriethylammonium chloride (a catalyst) were added and heated to 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. 16.0247 g of cardanol mercaptomaleic acid obtained in step (2) was then added and reacted at 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. The mixture was then cooled to below 80° C., 65.34 g of styrene was added, and the mixture was mixed uniformly to obtain a light yellow, transparent cardanol-based toughened vinyl photocurable resin.

[0050] The cardanol mercapto alcohol, cardanol mercaptomaleic acid, and cardanol-based toughened vinyl photocurable resin obtained in this example were subjected to Fourier transform infrared spectroscopy detection. The characteristic peaks of the detection results were basically consistent with those in Example 1, and are not described here for the sake of space.

[0051] Example 3

[0052] The preparation method of the cardanol-based toughened vinyl light-curing resin of this embodiment comprises the following steps:

[0053] (1) 150.0 g of cardanol, 85.9 g of mercaptoethanol, and 7.1 g of 1173 photoinitiator were added to a 500 mL round-bottom flask, magnetically stirred, and irradiated under 365 nm ultraviolet light for about 5 h. The reaction endpoint was reached when the double bond peak disappeared completely by infrared observation. 300 g of dichloromethane was then added to the round-bottom flask to dissolve the solution. The solution was transferred to a separatory funnel and washed with deionized water until the water layer was no longer turbid. Finally, the organic phase was rotary evaporated at 45 ° C to remove the solvent to obtain light yellow transparent cardanol mercapto alcohol.

[0054] (2) In a 500 mL three-necked flask, 60.0 g of the cardanol mercapto alcohol obtained in step (1) and 82.4 g of maleic anhydride were added. The mixture was stirred magnetically and heated to 80° C. in a nitrogen atmosphere for 24 h. The reaction product was tested by infrared spectroscopy. The reaction endpoint was reached when a carboxyl peak appeared. Ethyl acetate was added to the obtained reaction product to dissolve it, and the product was washed with deionized water. The ethyl acetate was then removed by rotary evaporation at 50° C. to obtain dark yellow, transparent cardanol mercaptomaleic acid.

[0055] (3) In a 500 mL round-bottom flask, 145.28 g of bisphenol A epoxy resin E-44 (molecular weight 454), 53.62 g of acrylic acid, 0.0436 g of hydroquinone (a polymerization inhibitor), and 1.0890 g of benzyltriethylammonium chloride (a catalyst) were added and heated to 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. 27.4709 g of cardanol mercaptomaleic acid obtained in step (2) was then added and reacted at 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. The mixture was then cooled to below 80° C., 65.3406 g of styrene was added, and the mixture was mixed uniformly to obtain a light yellow, transparent cardanol-based toughened vinyl photocurable resin.

[0056] The cardanol mercapto alcohol, cardanol mercaptomaleic acid, and cardanol-based toughened vinyl photocurable resin obtained in this example were subjected to Fourier transform infrared spectroscopy detection. The characteristic peaks of the detection results were basically consistent with those in Example 1, and are not described here for the sake of space.

[0057] Example 4

[0058] The preparation method of the cardanol-based toughened vinyl light-curing resin of this embodiment comprises the following steps:

[0059] (1) 150.0 g of cardanol, 85.9 g of mercaptoethanol, and 7.1 g of 1173 photoinitiator were added to a 500 mL round-bottom flask, magnetically stirred, and irradiated under 365 nm ultraviolet light for about 5 h. The reaction endpoint was reached when the double bond peak disappeared completely by infrared observation. 300 g of dichloromethane was then added to the round-bottom flask to dissolve the solution. The solution was transferred to a separatory funnel and washed with deionized water until the water layer was no longer turbid. Finally, the organic phase was rotary evaporated at 45 ° C to remove the solvent to obtain light yellow transparent cardanol mercapto alcohol.

[0060] (2) In a 500 mL three-necked flask, 60.0 g of the cardanol mercapto alcohol obtained in step (1) and 82.4 g of maleic anhydride were added. The mixture was stirred magnetically and heated to 80° C. in a nitrogen atmosphere for 24 h. The reaction product was tested by infrared spectroscopy. The reaction endpoint was reached when a carboxyl peak appeared. Ethyl acetate was added to the obtained reaction product to dissolve it, and the product was washed with deionized water. The ethyl acetate was then removed by rotary evaporation at 50° C. to obtain dark yellow, transparent cardanol mercaptomaleic acid.

[0061] (3) In a 500 mL round-bottom flask, 145.28 g of bisphenol A epoxy resin E-44 (molecular weight 454), 50.73 g of acrylic acid, 0.0470 g of hydroquinone (a polymerization inhibitor), and 1.1746 g of benzyltriethylammonium chloride (a catalyst) were added and heated to 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. 38.92 g of cardanol mercaptomaleic acid obtained in step (2) was then added and reacted at 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. The mixture was then cooled to below 80° C., 70.48 g of styrene was added, and the mixture was mixed uniformly to obtain a light yellow, transparent cardanol-based toughened vinyl photocurable resin.

[0062] The cardanol mercapto alcohol, cardanol mercaptomaleic acid, and cardanol-based toughened vinyl photocurable resin obtained in this example were subjected to Fourier transform infrared spectroscopy detection. The characteristic peaks of the detection results were basically consistent with those in Example 1, and are not described here for the sake of space.

[0063] Example 5

[0064] The preparation method of the cardanol-based toughened vinyl light-curing resin of this embodiment comprises the following steps:

[0065] (1) 150.0 g of cardanol, 85.9 g of mercaptoethanol, and 7.1 g of 1173 photoinitiator were added to a 500 mL round-bottom flask, magnetically stirred, and irradiated under 365 nm ultraviolet light for about 5 h. The reaction endpoint was reached when the double bond peak disappeared completely by infrared observation. 300 g of dichloromethane was then added to the round-bottom flask to dissolve the solution. The solution was transferred to a separatory funnel and washed with deionized water until the water layer was no longer turbid. Finally, the organic phase was rotary evaporated at 45 ° C to remove the solvent to obtain light yellow transparent cardanol mercapto alcohol.

[0066] (2) In a 500 mL three-necked flask, 60.0 g of the cardanol mercapto alcohol obtained in step (1) and 82.4 g of maleic anhydride were added. The mixture was stirred magnetically and heated to 80° C. in a nitrogen atmosphere for 24 h. The reaction product was tested by infrared spectroscopy. The reaction endpoint was reached when a carboxyl peak appeared. Ethyl acetate was added to the obtained reaction product to dissolve it, and the product was washed with deionized water. The ethyl acetate was then removed by rotary evaporation at 50° C. to obtain dark yellow, transparent cardanol mercaptomaleic acid.

[0067] (3) In a 500 mL round-bottom flask, 145.28 g of bisphenol A epoxy resin E-44 (molecular weight 454), 46.70 g of acrylic acid, 0.0494 g of hydroquinone (a polymerization inhibitor), and 1.2346 g of benzyltriethylammonium chloride (a catalyst) were added and heated to 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. 54.9417 g of cardanol mercaptomaleic acid obtained in step (2) was then added and reacted at 90° C. for about 3.5 hours until the acid value was less than 30 mgKOH / g. The mixture was then cooled to below 80° C., 74.08 g of styrene was added, and the mixture was mixed uniformly to obtain a light yellow, transparent cardanol-based toughened vinyl photocurable resin.

[0068] The cardanol mercapto alcohol, cardanol mercaptomaleic acid, and cardanol-based toughened vinyl photocurable resin obtained in this example were subjected to Fourier transform infrared spectroscopy detection. The characteristic peaks of the detection results were basically consistent with those in Example 1, and are not described here for the sake of space.

[0069] Comparative Example 1

[0070] The preparation method of the modified vinyl ester resin of this comparative example comprises the following steps:

[0071] In a 500 mL round-bottom flask, place 145.28 g of bisphenol A epoxy resin E-44 (molecular weight 454), 53.62 g of acrylic acid, 0.0398 g of hydroquinone (polymerization inhibitor), and 0.9945 g of benzyltriethylammonium chloride (catalyst). Heat to 90°C and allow to react until the acid value reaches less than 30 mgKOH / g. Then, cool to below 80°C, add 59.67 g of styrene, and mix thoroughly to obtain a modified vinyl ester resin.

[0072] In order to detect the comprehensive mechanical properties, thermal stability, antibacterial properties and corrosion resistance of the cardanol-based toughened vinyl photocurable resin prepared in the present invention, the cardanol-based toughened vinyl photocurable resin prepared in Examples 1-5 and the modified vinyl ester resin prepared in Comparative Example 1 were made into cured films, and then the obtained cured films were subjected to plastic tensile properties test, dynamic thermomechanical properties test, thermogravimetric test, antibacterial test and electrochemical test.

[0073] 1. Preparation of cured film

[0074] The cardanol-based toughened vinyl photocurable resin prepared in Examples 1-5 and the modified vinyl ester resin prepared in Comparative Example 1 were respectively mixed with 1173 photoinitiator in an amount of 5wt% of the total mass of the resin and irradiated with ultraviolet light for 3 minutes to obtain the product.

[0075] 2. Conduct plastic tensile properties test, dynamic thermomechanical properties test, thermogravimetric test, antibacterial test and electrochemical test on the prepared cured film

[0076] (1) Plastic tensile test: The tensile test was performed using a Shimadzu AGS-X 1 kN universal tester. The dumbbell-shaped sample specifications were based on GB / T 1040.2-2006, and the crosshead speed was 1 mm min. -1 Young's modulus is the ratio of tensile strength to elongation at break. For accuracy, three measurements were performed on each sample and the average value was taken.

[0077] (2) Dynamic thermomechanical properties test: The test was performed using a Netzsch DMA 242E dynamic thermomechanical instrument, with the tensile mode selected and the oscillation frequency set to 1 Hz. During the test, the sample was first cooled to -80°C with liquid nitrogen and kept at -50°C for 3 minutes, then heated at 5°C / min. -1 The sample was heated to 180°C at a rate of 100°F (32 mm x 5 mm x 3 mm). The sample dimensions were 32 mm x 5 mm x 3 mm (length x width x thickness). The glass transition temperature (Tg) of the cured film corresponds to the peak temperature on the tanδ vs. temperature curve. For accuracy, three measurements were taken for each sample and the average value was calculated.

[0078] (3) Thermogravimetric testing method: Thermogravimetric analysis was performed using a Netzsch STA 449C thermal analyzer. The temperature range required for the thermogravimetric testing of the sample was set to 35-650°C, and the heating rate was 10°C min -1 During the test, the nitrogen environment was maintained and the nitrogen introduction rate was 60 mL min -1 For the sake of accuracy, three measurements were performed on each sample and the average value was taken.

[0079] (4) Antibacterial test method: 1 g of the resin before curing and 1 g of the cured film after curing were added to 9 mL of liquid culture medium (consisting of 0.1 g of peptone, 0.05 g of beef extract, 0.05 g of sodium chloride, and 10 mL of distilled water), and 1 mL of bacterial solution (10 7 CUF / mL), then the resulting suspension was sealed in a test tube and placed in a constant temperature incubator for shaking culture for 24 hours. A suspension without resin or cured film sample (containing 9 mL of liquid culture medium and 1 mL of bacterial solution) was used as a blank control. The OD value of the suspension at 600 nm was measured using a UV-5500PC ultraviolet spectrophotometer. The survival rate of the strain was calculated according to the following formula: Survival rate (%) = OD x / OD0, where OD x is the OD value of the sample containing resin or cured film; OD0 is the OD value of the blank control. For the sake of accuracy, each sample was measured three times and the average value was taken.

[0080] (5) Electrochemical test method: The corrosion resistance of the metal sheet coated with the resin coating after being immersed in a 3.5 wt% NaCl aqueous solution was evaluated using the EIS technique in a CHI660E electrochemical workstation. 2 The sample was used as the working electrode and the saturated Ag / AgCl electrode was used as the reference electrode with an area of ​​2.5 cm 2 A three-electrode system was established using a platinum plate as the counter electrode. Before the experiment, the working electrode was immersed in a corrosive medium for 1 hour to ensure a stable open-circuit potential (OCP) value. EIS measurements were performed with the open-circuit potential stable, within a frequency range of 100 kHz to 0.01 Hz and a 20 mV sinusoidal amplitude. For accuracy, at least three specimens were prepared for each sample.

[0081] 3. Test results

[0082] (1) Comprehensive mechanical properties test results

[0083] The comprehensive mechanical properties test results of the cured film are shown in Table 1.

[0084] Table 1 Comprehensive mechanical properties test results of cured films

[0085] Tensile strength (MPa) Elongation at break (%) Tg(℃) Example 1 76.73 10.74 95.9 Example 2 77.79 11.57 89.4 Example 3 76.53 15.25 87.2 Example 4 76.70 9.32 82.8 Example 5 61.60 7.59 81.6 Comparative Example 1 57.44 5.23 96.5

[0086] As can be seen from Table 1, the cured film prepared by the cardanol-based toughening vinyl light-curing resin of Examples 1-5 of the present invention has a certain improvement in tensile properties relative to the cured film prepared by the vinyl ester resin modified by not adding cardanol mercaptomaleic acid of Comparative Example 1, and its tensile properties have a certain improvement, and glass transition temperature has declined. The tensile strength and elongation at break of the cured film prepared by the resin of Examples 1-5 of the present invention have a certain decline after reaching the peak value, and the addition amount of cardanol mercaptomaleic acid corresponding to the peak value is about 11% of the mass of E-44. The reason may be that the entanglement of long carbon chain and polymer chain and the rigid ring structure of cardanol mercaptomaleic acid improve the mechanical properties of the cured film, but when continuing to add cardanol mercaptomaleic acid, the long carbon chain introduced is too much, and the mechanical properties of the cured film can be caused to decline to a certain degree. Along with the difference in the amount of cardanol mercaptomaleic acid, the glass transition temperature of the obtained cured film presents regularity changes, and thus the glass transition temperature of the cured film can be regularly regulated and controlled.

[0087] (2) Thermal stability test results

[0088] The thermal stability test results of the cured films are shown in Table 2.

[0089] Table 2 Thermal stability test results of cured films

[0090] <![CDATA[T 10％ (℃)]]> <![CDATA[T 50％ (℃)]]> Residual carbon rate (%) Example 1 343.07 422.57 6.482 Example 2 303.50 413.50 6.143 Example 3 303.11 419.74 4.539 Example 4 306.22 416.72 6.805 Example 5 300.68 413.68 5.542 Comparative Example 1 383.97 428.47 8.855

[0091] As can be seen from Table 2, with the addition of cardanol mercaptomaleic acid, although a long bio-based carbon chain was introduced, the thermal stability of the resin did not decrease significantly due to the increase in cross-linking density, and the T 10％ All of them are higher than 300℃, indicating that the resin has good thermal stability.

[0092] (3) Antibacterial performance test results

[0093] The antibacterial performance test results of the resin before and after light curing are shown in Table 3.

[0094] Table 3 Antibacterial performance test results of resin before and after light curing

[0095]

[0096] As can be seen from Table 3, the cardanol-based toughened vinyl light-cured resin of the present invention can significantly reduce the survival rate of Escherichia coli and the survival rate of Staphylococcus aureus before and after solidification, relative to the vinyl ester resin modified by the addition of cardanol mercaptomaleic acid. Moreover, as the addition amount of cardanol mercaptomaleic acid increases, the survival rate of Escherichia coli and the survival rate of Staphylococcus aureus are further reduced. The reason may be that, as cardanol mercaptomaleic acid is added, the hydrogen atoms in its phenolic hydroxyl group can form hydrogen bonds with the phosphate group, carbonyl group, etc. on the microbial cell membrane. The interaction of this hydrogen bond can limit the free movement of cell membrane molecules, resulting in the colloidization of the cell membrane. This colloidization phenomenon can further affect the permeability and stability of the cell membrane, thereby enhancing the antibacterial effect of the phenolic hydroxyl group.

[0097] The difference in antimicrobial performance before and after curing of cardanol-toughened vinyl photocurable resins may be due to the fact that during the curing process, the phenolic hydroxyl groups of cardanol mercaptomaleic acid, acting as a curing agent, undergo an addition reaction with the oxygen atoms of the epoxy groups in the resin, forming new chemical bonds and promoting the crosslinking and curing of the epoxy resin. Since fewer phenolic hydroxyl groups in cardanol mercaptomaleic acid are available to form hydrogen bonds with phosphate and carbonyl groups on microbial cell membranes after curing, the antimicrobial performance of the cured resin decreases to a certain extent.

[0098] (4) Electrochemical test results

[0099] The electrochemical impedance spectroscopy of the resin coatings of Comparative Example 1, Example 1, Example 3 and Example 5 is shown in FIG. Figure 6 shown.

[0100] from Figure 6 It can be seen that at the initial stage of immersion, the Bode impedance curves of the resin coatings of Comparative Example 1, Example 1, Example 3, and Example 5 all show diagonal lines in a wide frequency range, and the |Z| 0.01Hz The value difference is small, both close to 10 11 Ω·cm 2 , showing excellent anti-corrosion performance. The Bode impedance curve of the resin coating of Comparative Example 1 shows that the resin coating of Comparative Example 1 shows a lower |Z| 0.01Hz Value, with the extension of immersion time, the resin coating of Comparative Example 1 within 60 days of immersion |Z| 0.01Hz The value quickly increased from 6.89×10 10 Ω·cm 2 Down to 7.24×10 7 Ω·cm 2 , which is nearly 3 orders of magnitude lower than the value at the initial immersion, and still does not reach a stable state during a longer immersion time, |Z| 0.01HzThe value is still decreasing, which means that the corrosion resistance of the resin coating of Comparative Example 1 has been decreasing. After 120 days of immersion, the |Z| 0.01Hz The value is 3.09×10 5 Ω·cm 2 .

[0101] From the Bode impedance curves of the resin coatings of Examples 1, 3, and 5, it can be seen that the resin coatings of Examples 1, 3, and 5 to which cardanol mercaptomaleic acid is added have |Z| 0.01Hz The value changes tend to be stable. After immersion for 180 days, the |Z| of the resin coatings of Example 1, Example 3, and Example 5 0.01Hz The values ​​were as high as 5.92×10 8 Ω·cm 2 , 6.42×10 9 Ω·cm 2 , 3.34×10 9 Ω·cm 2 , which only decreased by about 2 orders of magnitude compared to the |Z| of the resin coating of Comparative Example 1 after 120 days. 0.01Hz The value is about 5 orders of magnitude higher, indicating that the addition of cardanol mercaptomaleic acid improves the corrosion resistance of the resin coating.

[0102] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. Cardanol mercaptomaleic acid, characterized in that Its structural formula is:

2. The method for preparing the cardanol mercaptomaleic acid according to claim 1, wherein The steps include: Cardanol is subjected to a photo-click reaction with mercaptoethanol to obtain cardanol mercapto alcohol; and cardanol mercapto alcohol is subjected to an esterification reaction with maleic anhydride to obtain cardanol mercaptomaleic acid.

3. The method for preparing cardanol mercaptomaleic acid according to claim 2, wherein The steps include: In parts by mass, 140-160 parts of cardanol, 80-90 parts of mercaptoethanol, and 5-10 parts of photoinitiator are reacted under ultraviolet light for 3-7 hours to obtain cardanol mercapto alcohol; then 50-70 parts of cardanol mercapto alcohol and 80-90 parts of maleic anhydride are reacted at 50-120°C for 18-30 hours to obtain cardanol mercaptomaleic acid.

4. The method for preparing cardanol mercaptomaleic acid according to claim 3, wherein The photoinitiator is an ITX photoinitiator, an 1173 photoinitiator or a TPO photoinitiator.

5. Cardanol-based toughened vinyl light-curing resin, characterized in that: The raw material composition includes, by mass, 120-160 parts of epoxy resin, 0.9-1.4 parts of catalyst, 0.03-0.06 parts of polymerization inhibitor, 45-63 parts of monounsaturated carboxylic acid containing olefinic bond, 2-56 parts of cardanol mercaptomaleic acid according to claim 1, and 55-75 parts of active diluent.

6. The cardanol-based toughened vinyl photocurable resin according to claim 5, characterized in that: The epoxy resin is at least one of bisphenol A epoxy resin, bisphenol AD ​​epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin; The catalyst is at least one of benzyltriethylammonium chloride, dibutyltin dilaurate, triethylamine, and triphenylphosphine; The polymerization inhibitor is at least one of hydroquinone, p-tert-butylcatechol and catechol.

7. The cardanol-based toughened vinyl photocurable resin according to claim 5 or 6, characterized in that: The monobasic unsaturated carboxylic acid containing an olefinic bond is at least one of acrylic acid, methacrylic acid, crotonic acid, and phenylacrylic acid; The active diluent is at least one of styrene, α-methylstyrene, methyl acrylate, isobornyl acrylate, tripropylene glycol diacrylate, and trimethylolpropane triacrylate.

8. The method for preparing the cardanol-based toughened vinyl photocurable resin according to any one of claims 5 to 7, characterized in that: The steps include: The epoxy resin is reacted with a monounsaturated carboxylic acid containing an olefinic bond under the action of a catalyst and a polymerization inhibitor, and then the remaining epoxy groups are completely reacted with cardanol mercaptomaleic acid. Finally, an active diluent is added and mixed evenly to obtain the product.

9. The method for preparing the cardanol-based toughened vinyl light-curing resin according to claim 8, wherein: The steps include: The epoxy resin, catalyst, polymerization inhibitor, and olefinic monounsaturated carboxylic acid are reacted at 85-110° C. for 2-5 hours until the acid value is less than 30 mg KOH / g. Then, cardanol mercaptomaleic acid is added and the reaction is continued at 85-110° C. for 2-5 hours until the acid value is less than 30 mg KOH / g. The reaction is then cooled to below 80° C., and a reactive diluent is added and mixed uniformly to obtain the product.

10. Use of the cardanol-based toughened vinyl photocurable resin according to any one of claims 5 to 7 in the preparation of 3D printing materials, UV coatings, adhesives, packaging materials or anti-corrosion coatings.

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