Environment-friendly alkyd resin and preparation method thereof

Abstract

The invention relates to the field of resin, in particular to environment-friendly alkyd resin and a preparation method thereof. The alkyd resin is prepared from the following components in parts by weight: 20 to 35 parts of vegetable oil, 10 to 20 parts of polyhydric alcohol, 15 to 25 parts of polybasic acid, 2 to 5 parts of functional monomer, 0.5 to 3 parts of catalyst, 0.1 to 0.5 part of initiator, 0.1 to 1 part of antioxidant, 3 to 8 parts of cosolvent, 2 to 4 parts of neutralizer and 40 to 60 parts of deionized water. According to the present invention, the renewable bio-based raw material is adopted as the main body, the water-based treatment is combined, the final product uses water as the dispersion medium, and the volatile organic compound content is controlled at the low level, such that the organic solvent poisoning problem during the production, construction and application process of the traditional solvent-based resin is solved, and the green environmental protection requirement is met.

Description

Technical Field

[0001] This invention relates to the field of resins, and more specifically to an environmentally friendly alkyd resin and its preparation method. Background Technology

[0002] Alkyd resins are an important class of modified polyester resins obtained by polycondensation reaction of polyols, polyacids and fatty acids. Due to their advantages such as excellent adhesion, high film fullness, good weather resistance and relatively low cost, they have been widely used in coatings, inks, adhesives and other fields for a long time, and are one of the main film-forming substances in solvent-based coatings.

[0003] However, traditional alkyd resins typically rely on petrochemical raw materials such as phthalic anhydride, benzoic acid, and various petroleum-based fatty acids. Their preparation and use present significant environmental and health challenges. To achieve suitable application viscosity, traditional alkyd resin coatings contain large amounts of volatile organic compounds (VOCs), such as aromatic hydrocarbons, esters, and ketones. Against this backdrop, waterborne alkyd resins have emerged. Using water as the primary dispersion medium, they significantly reduce the use of organic solvents, decreasing organic solvent usage by approximately 400 kg per ton of coating. This results in a substantial reduction in VOC content and offers significant advantages such as safer production and application, and easier equipment cleaning.

[0004] Despite the significant environmental advantages of waterborne alkyd resins, they still have many problems in practical applications and performance: First, the drying speed is slow and the initial hardness is too low: the latent heat of vaporization of water is much higher than that of organic solvents, which leads to a significant extension of the surface drying and hard drying time of the paint film, affecting the construction efficiency; second, the water resistance and storage stability are poor, which is the core defect of waterborne alkyd resins. The ester bonds in the resin backbone are prone to hydrolysis in weakly alkaline or aqueous environments, leading to the breakage of the resin molecular chain.

[0005] Therefore, there is an urgent need for a new alkyd resin and its preparation method that can fundamentally or significantly reduce VOC emissions, while overcoming the shortcomings of existing waterborne alkyd resins in terms of coating performance (such as water resistance, drying speed, hardness), storage stability, or preparation process complexity, and providing an alkyd resin solution that combines excellent environmental protection characteristics and practical performance. Summary of the Invention

[0006] To address the problems existing in the prior art, the purpose of this invention is to provide an environmentally friendly alkyd resin and its preparation method.

[0007] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides an environmentally friendly alkyd resin, comprising the following components by weight: 20-35 parts vegetable oil, 10-20 parts polyol, 15-25 parts polyacid, 2-5 parts functional monomer, 0.5-3 parts catalyst, 0.1-0.5 parts initiator, 0.1-1 part antioxidant, 3-8 parts cosolvent, 2-4 parts neutralizer and 40-60 parts deionized water.

[0008] Preferably, the vegetable oil is one or more of linseed oil, tung oil, soybean oil, and castor oil.

[0009] Preferably, the polyol is one or more of sorbitol, glycerol, and pentaerythritol.

[0010] Preferably, the polybasic acid is a mixture of isophthalic acid, trimellitic anhydride, and bis(4-carboxyphenyl)phenylphosphine oxide.

[0011] Preferably, the polybasic acid is isophthalic acid, trimellitic anhydride, and bis(4-carboxyphenyl)phenylphosphine oxide in a weight ratio of 5-8:2-4:2-4.

[0012] Preferably, the functional monomer is a mixture of allyl borate pinacol ester and dodecafluoroheptyl methacrylate, wherein the weight ratio of allyl borate pinacol ester to dodecafluoroheptyl methacrylate is 1:1.5-2.5.

[0013] Preferably, the catalyst is an organotin catalyst, specifically one or more of dibutyltin dilaurate (DBTDL), dioctyltin dilaurate (DOTDL), and dibutyltin dioctanoate (DBTO).

[0014] Preferably, the initiator is benzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN).

[0015] Preferably, the antioxidant is a hindered phenolic antioxidant, specifically one or more of antioxidant 1010, antioxidant 1076, antioxidant 1098, and antioxidant 1135.

[0016] Preferably, the co-solvent is one or more of propylene glycol methyl ether, dipropylene glycol methyl ether, ethylene glycol methyl ether, and dipropylene glycol butyl ether.

[0017] Preferably, the neutralizing agent is ammonia or dimethylethanolamine.

[0018] Secondly, this invention proposes a method for preparing an environmentally friendly alkyd resin, comprising the following steps: Step 1: Weigh out vegetable oil, polyol and catalyst, mix them, and carry out alcoholysis reaction to obtain a mixed alcohol system; Step 2: Add all the polybasic acids into the mixed alcohol system to start the esterification polycondensation reaction and obtain the alkyd resin prepolymer. Step 3: Add a co-solvent to the alkyd resin prepolymer, dilute the system and cool it down. Mix the functional monomer and initiator evenly beforehand and slowly add them dropwise to the reaction system. After the addition is complete, keep the reaction at the temperature to obtain the alkyd resin composite system. Step 4: After cooling the alkyd resin composite system, add a neutralizing agent, stir evenly, add deionized water and shear stir, cool and filter to obtain environmentally friendly alkyd resin.

[0019] Preferably, in step 1, the alcoholysis reaction is carried out at a temperature of 230-240°C for 1-2 hours.

[0020] Preferably, in step 2, the temperature of the esterification polycondensation reaction is 230-240℃, and heating is stopped after the acid value drops to 15-20 mg KOH / g.

[0021] Preferably, in step 3, the dripping time is 2-3 hours, and after the dripping is completed, the reaction is kept at a constant temperature for 1.5-2.5 hours.

[0022] Preferably, in step 4, the shearing and stirring speed is 800-1200 rpm and the time is 30-40 min.

[0023] The beneficial effects of this invention are as follows: 1. This invention uses renewable bio-based raw materials as the main body, combined with water-based treatment, and the final product uses water as the dispersion medium to control the content of volatile organic compounds at a low level. This solves the problem of organic solvent toxicity in the production, construction and application of traditional solvent-based resins, and meets the requirements of green environmental protection.

[0024] 2. The preparation method of this invention adopts a one-pot, stepwise process that can be completed on traditional alkyd resin synthesis equipment without complex post-processing. The in-situ hybridization step of the functional monomers can be seamlessly integrated with the resin synthesis process, resulting in a simple, highly controllable process suitable for large-scale industrial production. By adjusting the ratio of polybasic acids to functional monomers, the performance of the final product can be easily adjusted to meet the application needs of various fields, from wood coating to industrial corrosion protection.

[0025] 3. This invention selects various environmentally friendly polyols, uses isophthalic acid to construct the resin backbone, and introduces bis(4-carboxyphenyl)phenylphosphine oxide as a reactive phosphorus-containing polyacid, which is chemically bonded to the resin skeleton, giving the resin certain flame retardancy while also enhancing its surface strength. Furthermore, this invention introduces two polymerizable monomers, allyl borate pinacol ester and dodecafluoroheptyl methacrylate, which synergistically work with the polyacid to give the resin coating high adhesion, water resistance, and chemical corrosion resistance, achieving the integration of multiple high-performance properties from a single resin. Detailed Implementation

[0026] The technical solution of the present invention is illustrated below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or defining the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0027] To better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0028] The present invention will be further described below with reference to the following embodiments.

[0029] Example 1 An environmentally friendly alkyd resin, comprising the components listed in Table 1 by weight:

[0030] The preparation method of the above-mentioned environmentally friendly alkyd resin includes the following steps: Step 1: Weigh 25 parts linseed oil, 15 parts glycerin and 1.5 parts DBTDL, add them to a reaction vessel equipped with a stirrer, thermometer and condenser, heat to 235℃ under nitrogen protection, keep the temperature for alcoholysis reaction for 1.5h, take a sample to test the transparency of the alcoholysis liquid (no layering, clear), and obtain a mixed alcohol system. Step 2: Add 20 parts of polybasic acid (10 parts of isophthalic acid, 5 parts of trimellitic anhydride, and 5 parts of bis(4-carboxyphenyl)phenylphosphine oxide) to the mixed alcohol system, maintain the temperature at 235℃ to carry out the esterification polycondensation reaction, take samples every 30 minutes to detect the acid value, and stop heating when the acid value drops to 18 mg KOH / g to obtain alkyd resin prepolymer; Step 3: Add 5 parts of propylene glycol methyl ether to the alkyd resin prepolymer, stir to dilute and cool to 120°C. Dissolve 3 parts of functional monomers (1 part of allyl borate pinacol ester and 2 parts of dodecafluoroheptyl methacrylate) in a premixed mixture with 0.3 parts of BPO. Slowly add the mixture dropwise to the reaction system through a constant pressure dropping funnel over a period of 2.5 hours. After the addition is complete, maintain the temperature at 120°C for 2 hours to obtain the alkyd resin composite system. Step 4: Cool the alkyd resin composite system to 60°C, add 3 parts ammonia water, stir for 15 minutes until the system is uniform, then add 50 parts deionized water, adjust the shear stirring speed to 1000 rpm, continue stirring for 35 minutes, cool to room temperature, and filter with a 200-mesh filter cloth to obtain an environmentally friendly alkyd resin emulsion.

[0031] Example 2 An environmentally friendly alkyd resin, comprising the components listed in Table 2 by weight:

[0032] The preparation method of the above-mentioned environmentally friendly alkyd resin includes the following steps: Step 1: Weigh 15 parts soybean oil, 15 parts castor oil, 6 parts sorbitol, 6 parts pentaerythritol and 0.8 parts DOTDL, add them to the reaction vessel, heat to 232℃ under nitrogen protection, and perform alcoholysis reaction for 1.2h. The alcoholysis solution is found to be free of stratification, and a mixed alcohol system is obtained. Step 2: Add 22 parts of polybasic acid (12.83 parts of isophthalic acid, 3.67 parts of trimellitic anhydride, and 5.5 parts of bis(4-carboxyphenyl)phenylphosphine oxide), and carry out esterification polycondensation reaction at 232℃. Stop heating when the acid value drops to 16 mg KOH / g to obtain alkyd resin prepolymer. Step 3: Add 6 parts of dipropylene glycol methyl ether to dilute and cool to 115℃. Mix and dissolve 4 parts of functional monomer (1.6 parts of allyl borate pinacol ester and 2.4 parts of dodecafluoroheptyl methacrylate) with 0.2 parts of AIBN. Add the monomer dropwise over 2 hours. After the addition is complete, keep the mixture at 115℃ for 1.5 hours to obtain the alkyd resin composite system. Step 4: Cool to 55℃, add 2.5 parts of dimethylethanolamine and stir evenly, add 45 parts of deionized water, shear and stir at 800 rpm for 40 minutes, cool and filter to obtain environmentally friendly alkyd resin emulsion.

[0033] Example 3 An environmentally friendly alkyd resin, comprising the components listed in Table 3 by weight:

[0034] The preparation method of the above-mentioned environmentally friendly alkyd resin includes the following steps: Step 1: Weigh 22 parts tung oil, 12 parts glycerol, 6 parts sorbitol and 2 parts DBTO, protect the reaction vessel with nitrogen, heat to 238℃, and carry out alcoholysis reaction for 1.8h to obtain a mixed alcohol system; Step 2: Add 18 parts of polybasic acid (6.92 parts of isophthalic acid, 5.54 parts of trimellitic anhydride, and 5.54 parts of bis(4-carboxyphenyl)phenylphosphine oxide), and perform esterification and polycondensation reaction at 238℃ until the acid value reaches 17 mg KOH / g, then stop heating; Step 3: Add 4 parts of ethylene glycol methyl ether to dilute and cool to 125℃. Mix 2.5 parts of functional monomer (0.71 parts of allyl borate pinacol ester and 1.79 parts of dodecafluoroheptyl methacrylate) with 0.4 parts of BPO. Add the monomer dropwise over 3 hours. After the addition is complete, keep the mixture at 125℃ for 2.5 hours. Step 4: Cool to 65℃, add 3.5 parts ammonia water and stir, add 55 parts deionized water, shear and stir at 1200 rpm for 30 minutes, cool and filter to obtain the product.

[0035] Example 4 An environmentally friendly alkyd resin, comprising the components listed in Table 4 by weight:

[0036] The preparation method of the above-mentioned environmentally friendly alkyd resin includes the following steps: Step 1: Weigh 19.8 parts of flaxseed oil, 13.2 parts of soybean oil, 14 parts of pentaerythritol and 1 part of composite catalyst (0.5 parts of dibutyltin dilaurate + 0.5 parts of dioctyltin dilaurate), add them to the reaction vessel, heat to 235℃ under nitrogen protection, and maintain the temperature for 1.5 h for alcoholysis reaction. The alcoholysis solution is clear and without layering, and a mixed alcohol system is obtained. Step 2: Add 24 parts of polybasic acid (13.72 parts of isophthalic acid, 5.14 parts of trimellitic anhydride, and 5.14 parts of bis(4-carboxyphenyl)phenylphosphine oxide) to the mixed alcohol system, maintain the esterification polycondensation reaction at 235℃, and check the acid value periodically. Stop heating when the acid value drops to 19 mg KOH / g to obtain alkyd resin prepolymer; Step 3: Add 7 parts of dipropylene glycol butyl ether, stir to dilute and cool to 120℃. Dissolve 4.5 parts of functional monomer (1.5 parts of allyl borate pinacol ester and 3 parts of dodecafluoroheptyl methacrylate) in a premixed mixture with 0.3 parts of AIBN. Add the mixture slowly through a constant pressure dropping funnel over a period of 2.5 hours. After the addition is complete, maintain the temperature at 120℃ for 2 hours to obtain the alkyd resin composite system. Step 4: Cool the system to 60°C, add 2 parts of dimethylethanolamine, stir for 20 minutes until homogeneous, add 48 parts of deionized water, adjust the shear stirring speed to 1000 rpm, continue stirring for 35 minutes, cool to room temperature, and filter with a 200-mesh filter cloth to obtain an environmentally friendly alkyd resin emulsion.

[0037] Comparative Example 1 An environmentally friendly alkyd resin, by weight, comprises the components shown in Table 5:

[0038] The preparation method of the above-mentioned environmentally friendly alkyd resin is completely consistent with that of Example 1 (only the functional monomer is not added in step 3, and the other process parameters remain unchanged).

[0039] Comparative Example 2 An environmentally friendly alkyd resin, comprising the components shown in Table 6 by weight:

[0040] The preparation method of the above-mentioned environmentally friendly alkyd resin is completely consistent with that of Example 1 (only the polybasic acid component is adjusted, and the other process parameters remain unchanged).

[0041] Comparative Example 3 An environmentally friendly alkyd resin, comprising the components listed in Table 7 by weight:

[0042] The preparation method of the above-mentioned environmentally friendly alkyd resin is completely consistent with that of Example 1 (the polyacid composition is adjusted, there is no functional monomer drop-addition step, and the other process parameters remain unchanged).

[0043] Experimental performance testing: The performance of the aqueous alkyd resins prepared in Examples 1-4 and Comparative Examples 1-3 was tested. The performance indicators and test methods are shown in Table 8.

[0044] The test results are shown in Table 9:

[0045] As can be seen from the data of Example 1 and Comparative Example 1 in Table 9, the water resistance, adhesion, and surface hardness of Example 1 are significantly better than those of Comparative Example 1. As can be seen from the data of Example 1 and Comparative Example 2, the surface hardness and storage stability of Example 1 are significantly better than those of Comparative Example 2. As can be seen from the data of Comparative Example 3, the introduction of polybasic acid without bis(4-carboxyphenyl)phenylphosphine oxide and functional monomers does not simply result in the performance improvement of the two, thus further confirming the synergistic effect of the two in functional complementarity.

[0046] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0047] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An environmentally friendly alkyd resin, characterized by, in parts by weight, Includes the following ingredients: 20-35 parts vegetable oil, 10-20 parts polyol, 15-25 parts polyacid, 2-5 parts functional monomer, 0.5-3 parts catalyst, 0.1-0.5 parts initiator, 0.1-1 part antioxidant, 3-8 parts solubilizer, 2-4 parts neutralizer and 40-60 parts deionized water; The polybasic acid is a mixture of isophthalic acid, trimellitic anhydride, and bis(4-carboxyphenyl)phenylphosphine oxide; the functional monomer is a mixture of allyl borate pinacol ester and dodecafluoroheptyl methacrylate.

2. The environmentally friendly alkyd resin according to claim 1, characterized in that, calculated by weight parts, The vegetable oil is one or more of linseed oil, tung oil, soybean oil, and castor oil.

3. The environmentally friendly alkyd resin according to claim 1, characterized in that, calculated by weight parts, The polyol is one or more of sorbitol, glycerol, and pentaerythritol.

4. The environmentally friendly alkyd resin according to claim 1, characterized in that, calculated by weight parts, The polybasic acid is isophthalic acid, trimellitic anhydride, and bis(4-carboxyphenyl)phenylphosphine oxide in a weight ratio of 5-8:2-4:2-4.

5. The environmentally friendly alkyd resin according to claim 1, characterized in that, calculated by weight parts, The weight ratio of allyl borate pinacol ester and dodecafluoroheptyl methacrylate is 1:1.5-2.

5.

6. The environmentally friendly alkyd resin according to claim 1, characterized in that, calculated by weight parts, The catalyst is one or more of dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dioctanoate.

7. The environmentally friendly alkyd resin according to claim 1, characterized in that, calculated by weight parts, The initiator is benzoyl peroxide or azobisisobutyronitrile.

8. The environmentally friendly alkyd resin according to claim 1, characterized in that, calculated by weight parts, The antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 1098, and antioxidant 1135.

9. The environmentally friendly alkyd resin according to claim 1, characterized in that, calculated by weight parts, The cosolvent is one or more of propylene glycol methyl ether, dipropylene glycol methyl ether, ethylene glycol methyl ether, and dipropylene glycol butyl ether; the neutralizing agent is ammonia or dimethylethanolamine.

10. A method for preparing the environmentally friendly alkyd resin according to claim 1, characterized in that, Includes the following steps: Step 1: Weigh out vegetable oil, polyol and catalyst, mix them, and carry out alcoholysis reaction to obtain a mixed alcohol system; Step 2: Add all the polybasic acids into the mixed alcohol system to start the esterification polycondensation reaction and obtain the alkyd resin prepolymer. Step 3: Add a co-solvent to the alkyd resin prepolymer, dilute the system and cool it down. Mix the functional monomer and initiator evenly beforehand and slowly add them dropwise to the reaction system. After the addition is complete, keep the reaction at the temperature to obtain the alkyd resin composite system. Step 4: After cooling the alkyd resin composite system, add a neutralizing agent, stir evenly, add deionized water and shear stir, cool and filter to obtain environmentally friendly alkyd resin.

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