Method for synthesizing waterborne branched alkyd resin from fatty acid methyl ester

Abstract

The invention discloses a method for synthesizing waterborne branched alkyd resin from fatty acid methyl ester. The method comprises the following steps: (1) carrying out gradual branched synthesis on trimellitic anhydride serving as a molecular center and glycerol under the action of a catalyst; (2) carrying out ring-opening reaction on the obtained product, phthalic anhydride and maleic anhydride; (3) performing transesterification on unsaturated fatty acid methyl ester, pentaerythritol and a catalyst to obtain an intermediate substance with a fatty acid chain as a terminal group; and (4) adding the intermediate substance into the material in the step (2), heating, carrying out large reflux esterification reaction, cooling, and extracting the water-carrying agent xylene to obtain the branched alkyd resin molecule with the fatty acid chain as the end group. And (5) subjecting the material, acrylic acid, styrene, methyl methacrylate, propylene glycol monomethyl ether and tert-butyl peroxybenzoate to molecular water-based treatment of the branched alkyd resin, and carrying out filtering and packaging so as to obtain the qualified water-based branched alkyd resin. The water-based branched alkyd resin synthesized by the invention has the advantages of high gloss, high drying speed, high hardness, good adhesive force and excellent storage stability.

Description

Technical Field

[0001] The invention relates to the technical field of coating resin synthesis methods, and in particular to a method for synthesizing waterborne branched alkyd resin by utilizing fatty acid methyl ester. Technical Background

[0002] At present, the water-based alkyd resins on the domestic market are mainly water-based acrylic acid modified alkyd resins, which are modified by monomers such as styrene and acrylic acid, and acrylic acid provides hydrophilic groups, and is neutralized with neutralizers such as dimethylethanolamine to achieve water-based properties. The modified water-based alkyd resin has excellent dryness, and the surface dryness can reach within 30min / 25℃. However, the water-based alkyd resin modified by monomers such as styrene and acrylic acid, the monomer dosage accounts for about 28-35% of the solid resin, so the oiliness of the alkyd resin after modification will be greatly reduced, thereby affecting the gloss of the paint (the same paint making formula, the same amount of solid resin, the longer the oiliness, the greater the gloss). Therefore, it is necessary to develop a preparation method for a water-based branched alkyd resin, so that the prepared branched alkyd resin has a three-dimensional structure, a regular molecular structure, high solubility, high solid content and low viscosity. Its molecular end group is mainly grafted with unsaturated fatty acid methyl ester, so the oiliness is long and the gloss is high. After being modified by monomers such as styrene and acrylic acid, it also has excellent dryness, hardness and adhesion. Summary of the invention

[0003] The invention aims to provide a method for synthesizing a water-based branched alkyd resin from fatty acid methyl ester, so that the synthesized water-based branched alkyd resin has the characteristics of high gloss, fast drying, high hardness, good adhesion and excellent storage stability.

[0004] To achieve the above purpose, the method for synthesizing water-based branched alkyd resin from fatty acid methyl ester of the present invention has the following operating steps:

[0005] The first step is to carry out stepwise branching synthesis with trimellitic anhydride as the molecular center, and prepare materials according to the following mass fraction ratio: 1.0-2.2 parts of trimellitic anhydride, 1.8-2.5 parts of 95% mass ratio concentration of glycerol, and 0.01-0.02 parts of catalyst organotin; firstly, the prepared materials trimellitic anhydride, 95% mass ratio concentration of glycerol and catalyst organotin are added into a reaction kettle with a thermometer, a condenser and a water separator, and heated by stirring, and the temperature is raised to 178-196° C. to react for 1.5-2 hours, and the trimellitic anhydride reacts with excess glycerol, and the primary hydroxyl group of glycerol reacts with the carboxyl group and the anhydride group of trimellitic anhydride first, and the water generated by the esterification reaction is removed, and the temperature is lowered until the acid value reaches 0.2-1 mgKOH / g, and when it is close to room temperature, it is further cooled to 10-15° C. with chilled water, and then filtered, and washed with water to remove excess glycerol, to obtain a reaction product;

[0006] Step 2: Continue to carry out a ring-opening reaction with the product obtained in step 1 and phthalic anhydride and maleic anhydride, prepare materials according to the following mass fraction ratio: phthalic anhydride 5.0-6.5 parts, maleic anhydride 0.65-0.85 parts and the mass of all the reaction products obtained in step 1; add all the above materials into a reaction kettle equipped with a thermometer, a condenser and a water separator, stir and heat, heat to 140-145° C. and keep warm for 3-4 hours, phthalic anhydride and maleic anhydride carry out a ring-opening reaction, and no cooling is required after the reaction is completed;

[0007] Step 3: Synthesis of fatty acid chains with terminal groups; prepare materials according to the following mass fraction ratio: 37-49 parts of unsaturated fatty acid methyl ester, 65-75 parts of pentaerythritol and 0.01-0.02 parts of catalyst lithium hydroxide; add all the above materials into a reaction kettle with a thermometer, a condenser and a water separator, stir and heat, and carry out ester exchange reaction after heating to 240-256°C. When the material changes from hot transparent to translucent, the tolerance is measured after 60-75 minutes, and the material: 95% ethanol = 1:4 to make it transparent, cool down, and obtain an intermediate substance with fatty acid chains as terminal groups;

[0008] Step 4: Synthesis of branched alkyd resin with fatty acid chain as terminal group: add the intermediate substance synthesized in the third step to the material in the second step, mix evenly, heat and stir to raise the temperature, and carry out reflux esterification reaction at 220-230°C. When the reaction reaches an acid value of ≤6mgKOH / g, cool to 130°C-140°C for insulation, and vacuum extract the water-containing xylene to obtain a branched alkyd resin molecule with fatty acid chain as terminal group;

[0009] Step 5: Make the branched alkyd resin molecule water-based. Prepare the following materials according to the following mass fraction ratio: 2.5-3.5 parts of acrylic acid, 14-18 parts of styrene, 4.0-5.5 parts of methyl methacrylate, 8-9 parts of propylene glycol methyl ether and 1-1.5 parts of tert-butyl perbenzoate; add the above materials to the drop stirring tank according to the proportion and stir evenly; keep the branched alkyd resin temperature in the reactor at 140±2℃, add the mixed monomers in the drop stirring tank evenly at 4.8 -5.5 hours of dripping is slowly added into the reactor, and the temperature is kept for 0.5-1 hour after the addition is completed. After the insulation is completed, 0.03-0.05 parts of initiator tert-butyl perbenzoate is added at one time, and the temperature is kept for another 2-3 hours, and then the temperature is lowered to below 80°C, 7.5-8.5 parts of propylene glycol methyl ether, 16-18 parts of propylene glycol butyl ether and 4.5-7.0 parts of dimethylethanolamine are added, and the mixture is stirred evenly, filtered and packaged to obtain a qualified water-based branched alkyd resin.

[0010] The molecular structure and reaction formula of the materials in the pre-synthesized branched alkyd resin in the above steps 1 to 4 are as follows:

[0011]

[0012]

[0013]

[0014]

[0015] The method for synthesizing water-based branched alkyd resin from fatty acid methyl ester has the following technical characteristics and beneficial effects:

[0016] 1. The water-based branched alkyd resin is prepared using fatty acid methyl ester, and the resin has a regular molecular structure, high solid content and low viscosity;

[0017] 2. The end groups are all unsaturated fatty acid chains, which are super long oil. After being modified with monomers such as acrylic acid and styrene and made water-based, they are still long oil and have excellent gloss.

[0018] 3. Use acrylic acid, styrene and methyl methacrylate monomers to modify the branched alkyd resin, introduce hydrophilic groups, and make it water-based. This can effectively improve the drying properties of the branched alkyd resin and ensure that the alkyd resin with a long oil content can also dry quickly. DETAILED DESCRIPTION

[0019] The method for synthesizing waterborne branched alkyd resin from fatty acid methyl ester of the present invention is further described in detail below in conjunction with specific embodiments.

[0020] Example 1

[0021] (1) Stepwise branching synthesis with trimellitic anhydride as the molecular center: prepare the materials according to the following mass fraction ratio: 1.6 parts of trimellitic anhydride, 2.4 parts of 95% mass ratio glycerol, and 0.02 parts of catalyst organotin; first, add the prepared materials trimellitic anhydride, 95% glycerol and catalyst organotin into a reaction kettle equipped with a thermometer, a condenser and a water separator, stir and heat, raise the temperature to 178-196° C. and react for 1.5-2 hours, trimellitic anhydride reacts with excess glycerol, and the primary hydroxyl group of glycerol reacts with the carboxyl group and anhydride group of trimellitic anhydride first, and the water generated by the esterification reaction is removed, and the temperature is lowered until the acid value reaches 0.2-1 mgKOH / g, and when it is close to room temperature, continue to cool to 10-15° C. with chilled water, filter, and wash with water to remove excess glycerol to obtain a reaction product.

[0022] (2) The product obtained in step (1) is further subjected to a ring-opening reaction with phthalic anhydride and maleic anhydride. The materials are prepared according to the following mass fraction ratio: 6.3 parts of phthalic anhydride, 0.83 parts of maleic anhydride and the mass of the total product obtained in the first step; all of the above materials are added to a reaction kettle equipped with a thermometer, a condenser and a water separator, and the mixture is heated with stirring to 140-145° C. and kept at this temperature for 3-4 hours to allow the phthalic anhydride and maleic anhydride to undergo a ring-opening reaction. After the reaction is completed, there is no need to cool down the temperature.

[0023] (3) For the synthesis of fatty acid chains as end groups, the following materials are prepared according to the following mass fraction ratio: 45.2 parts of unsaturated fatty acid methyl ester, 71.1 parts of pentaerythritol and 0.02 parts of catalyst lithium hydroxide; all of the above materials are added to a reaction kettle equipped with a thermometer, a condenser and a water separator, and stirred and heated to 240-256° C. for ester exchange reaction. When the material changes from heat transparent to translucent, the tolerance is measured 60-75 minutes later. The material: 95% ethanol = 1:4 to make it transparent, and the temperature is lowered to obtain an intermediate substance with fatty acid chains as end groups.

[0024] (4) Synthesis of branched alkyd resin with fatty acid chain as the terminal group. The intermediate substance synthesized in the third step is added to the material in the second step, the mixture is stirred evenly, and the mixture is heated to a temperature of 220-230° C. and subjected to a large reflux esterification reaction until the acid value is ≤6 mgKOH / g. The mixture is cooled to 130° C.-140° C. and kept warm. The xylene with water is extracted by vacuum to obtain a branched alkyd resin molecule with fatty acid chain as the terminal group. The molecule has a regular structure, low viscosity, and extremely long oil content.

[0025] (5) Water-based branched alkyd resin molecules. Prepare the following materials in the following mass fraction ratio: 2.8 parts of acrylic acid, 15.1 parts of styrene, 4.5 parts of methyl methacrylate, 8 parts of propylene glycol methyl ether and 1 part of tert-butyl perbenzoate; add the above materials to the dropping stirring tank in proportion and stir evenly. The temperature of the branched alkyd resin in the reactor is 140±2°C, and the mixed monomers stirred evenly in the dropping stirring tank are slowly added to the reactor at a dropping speed of 4.8-5.5 hours. After the addition is completed, keep warm for 0.5-1 hour. After the insulation is completed, add 0.03 parts of initiator tert-butyl perbenzoate at one time, and keep warm for another 2-3 hours, and then cool to less than 80°C, add 7.5 parts of propylene glycol methyl ether, 16.5 parts of propylene glycol butyl ether and 5 parts of dimethylethanolamine, stir evenly, filter and package, and obtain qualified water-based branched alkyd resin.

[0026] Example 2

[0027] (1) Stepwise branching synthesis with trimellitic anhydride as the molecular center: prepare the materials according to the following mass fraction ratio: 1.3 parts of trimellitic anhydride, 1.9 parts of 95% mass ratio glycerol, and 0.02 parts of catalyst organotin; first, add the prepared materials trimellitic anhydride, 95% glycerol and catalyst organotin into a reaction kettle equipped with a thermometer, a condenser and a water separator, stir and heat, raise the temperature to 178-196° C. and react for 1.5-2 hours, trimellitic anhydride reacts with excess glycerol, and the primary hydroxyl group of glycerol reacts with the carboxyl group and anhydride group of trimellitic anhydride first, and the water generated by the esterification reaction is removed, and the temperature is lowered until the acid value reaches 0.2-1 mgKOH / g, and when it is close to room temperature, continue to cool to 10-15° C. with chilled water, filter, and wash with water to remove excess glycerol to obtain a reaction product.

[0028] (2) The product obtained in step (1) is further subjected to a ring-opening reaction with phthalic anhydride and maleic anhydride. The materials are prepared according to the following mass fraction ratio: 5.2 parts of phthalic anhydride, 0.65 parts of maleic anhydride and the mass of the total product obtained in the first step; all of the above materials are added to a reaction kettle equipped with a thermometer, a condenser and a water separator, and the mixture is heated with stirring to 140-145° C. and kept at this temperature for 3-4 hours to allow the phthalic anhydride and maleic anhydride to undergo a ring-opening reaction. After the reaction is completed, there is no need to cool down the temperature.

[0029] (3) For the synthesis of fatty acid chains as end groups, the following materials are prepared according to the following mass fraction ratio: 38.2 parts of unsaturated fatty acid methyl ester, 58.8 parts of pentaerythritol and 0.02 parts of catalyst lithium hydroxide; all of the above materials are added to a reaction kettle equipped with a thermometer, a condenser and a water separator, and stirred and heated to 240-256° C. for ester exchange reaction. When the material changes from heat transparent to translucent, the tolerance is measured 60-75 minutes later. The material: 95% ethanol = 1:4 to make it transparent, and the temperature is lowered to obtain an intermediate substance with fatty acid chains as end groups.

[0030] (4) Synthesis of branched alkyd resin with fatty acid chain as the terminal group. The intermediate substance synthesized in the third step is added to the material in the second step, the mixture is stirred evenly, and the mixture is heated to a temperature of 220-230° C. and subjected to a large reflux esterification reaction until the acid value is ≤6 mgKOH / g. The mixture is cooled to 130° C.-140° C. and kept warm. The xylene with water is extracted by vacuum to obtain a branched alkyd resin molecule with fatty acid chain as the terminal group. The molecule has a regular structure, low viscosity, and extremely long oil content.

[0031] (5) Water-based branched alkyd resin molecules. Prepare the following materials in the following mass fraction ratio: 3.0 parts of acrylic acid, 15.0 parts of styrene, 4.7 parts of methyl methacrylate, 8 parts of propylene glycol methyl ether and 1 part of tert-butyl perbenzoate; add the above materials to the dropping stirring tank in proportion and stir evenly. The temperature of the branched alkyd resin in the reactor is 140±2°C, and the mixed monomers stirred evenly in the dropping stirring tank are slowly added to the reactor at a dropping speed of 4.8-5.5 hours. After the addition is completed, keep warm for 0.5-1 hour. After the insulation is completed, add 0.03 parts of initiator tert-butyl perbenzoate at one time, keep warm for another 2-3 hours, and then cool to less than 80°C, add 7.5 parts of propylene glycol methyl ether, 16.5 parts of propylene glycol butyl ether and 5.1 parts of dimethylethanolamine, stir evenly, filter and package, and obtain a qualified water-based branched alkyd resin.

[0032] The technical indicators of the water-based branched alkyd resin prepared in the above two embodiments and the existing water-based acrylic acid modified alkyd resin products are compared in the following table (the same blending paint formula is used for paint making, and the dry film thickness is 50um):

[0033]

[0034] As can be seen from the table, both embodiments use unsaturated fatty acid methyl ester to synthesize water-based branched alkyd resin, and the experimental results have consistent repeatability. Compared with the water-based modified alkyd resin circulating on the market, the water-based branched alkyd resin has excellent gloss, and the drying property and hardness are better than those of ordinary water-based alkyd resin. The heat storage also meets the storage requirements of water-based alkyd resin.

Claims

1. A method for synthesizing water-based branched alkyd resin from fatty acid methyl esters, characterized in that: The steps are as follows: The first step is to carry out stepwise branching synthesis with trimellitic anhydride as the molecular center, and prepare materials according to the following mass fraction ratio: 1.0-2.2 parts of trimellitic anhydride, 1.8-2.5 parts of 95% mass ratio concentration of glycerol, and 0.01-0.02 parts of catalyst organotin; firstly, the prepared materials trimellitic anhydride, 95% mass ratio concentration of glycerol and catalyst organotin are added into a reaction kettle with a thermometer, a condenser and a water separator, and heated by stirring, and the temperature is raised to 178-196° C. to react for 1.5-2 hours, and the trimellitic anhydride reacts with excess glycerol, and the primary hydroxyl group of glycerol reacts with the carboxyl group and the anhydride group of trimellitic anhydride first, and the water generated by the esterification reaction is removed, and the temperature is lowered until the acid value reaches 0.2-1 mgKOH / g, and when it is close to room temperature, it is further cooled to 10-15° C. with chilled water, and then filtered, and washed with water to remove excess glycerol, to obtain a reaction product; Step 2: Continue to carry out a ring-opening reaction with the product obtained in step 1 and phthalic anhydride and maleic anhydride, prepare materials according to the following mass fraction ratio: phthalic anhydride 5.0-6.5 parts, maleic anhydride 0.65-0.85 parts and the mass of all the reaction products obtained in step 1; add all the above materials into a reaction kettle equipped with a thermometer, a condenser and a water separator, stir and heat, heat to 140-145° C. and keep warm for 3-4 hours, phthalic anhydride and maleic anhydride carry out a ring-opening reaction, and no cooling is required after the reaction is completed; Step 3: Synthesis of fatty acid chains at the end; Prepare the materials according to the following mass fraction ratio: 37-49 parts of unsaturated fatty acid methyl ester, 65-75 parts of pentaerythritol and 0.01-0.02 parts of catalyst lithium hydroxide; add all the above materials into a reaction kettle equipped with a thermometer, a condenser and a water separator, stir and heat, and carry out ester exchange reaction after heating to 240-256°C. When the material changes from hot transparent to translucent, the tolerance is measured after 60-75 minutes. The material: 95% ethanol = 1:4 to make it transparent, cool down, and obtain an intermediate substance with a fatty acid chain as the terminal group; Step 4: Synthesis of branched alkyd resin with fatty acid chain as terminal group: add the intermediate substance synthesized in the third step to the material in the second step, mix evenly, heat and stir to raise the temperature, and carry out reflux esterification reaction at 220-230°C. When the reaction reaches an acid value of ≤6mgKOH / g, cool to 130°C-140°C for insulation, and vacuum extract the water-containing xylene to obtain a branched alkyd resin molecule with fatty acid chain as terminal group; Step 5: Make the branched alkyd resin molecule water-based. Prepare the following materials according to the following mass fraction ratio: 2.5-3.5 parts of acrylic acid, 14-18 parts of styrene, 4.0-5.5 parts of methyl methacrylate, 8-9 parts of propylene glycol methyl ether and 1-1.5 parts of tert-butyl perbenzoate; add the above materials to the drop stirring tank according to the proportion and stir evenly; keep the branched alkyd resin temperature in the reactor at 140±2℃, add the mixed monomers in the drop stirring tank evenly at 4.8 -5.5 hours of dripping is slowly added into the reactor, and the temperature is kept for 0.5-1 hour after the addition is completed. After the insulation is completed, 0.03-0.05 parts of initiator tert-butyl perbenzoate is added at one time, and the temperature is kept for another 2-3 hours, and then the temperature is lowered to below 80°C, 7.5-8.5 parts of propylene glycol methyl ether, 16-18 parts of propylene glycol butyl ether and 4.5-7.0 parts of dimethylethanolamine are added, and the mixture is stirred evenly, filtered and packaged to obtain a qualified water-based branched alkyd resin.

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