Bio-polyester modified acrylic acid secondary dispersion as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of high polymer materials, and provides a bio-based polyester modified acrylic acid secondary dispersion as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing bio-based dihydric alcohol, glycerol, bio-based dibasic acid without carbon-carbon double bonds, a catalyst and an antioxidant, and carrying out first esterification reaction to obtain an esterified intermediate; adding bio-based binary acid containing carbon-carbon double bonds into the esterification intermediate, and carrying out a second esterification reaction to obtain a bio-based polyester intermediate; dropwise adding the mixed monomer I into the bio-based polyester intermediate to obtain a core layer intermediate; dropwise adding a mixed monomer II into the core-layer intermediate, and carrying out a copolymerization reaction to obtain a core-shell intermediate; and sequentially neutralizing and dispersing the core-shell intermediate. The bio-based polyester modified acrylic acid secondary dispersion disclosed by the invention is high in solid content, low in viscosity, strong in emulsifying ability and high in bio-based content; a prepared paint film is relatively high in flexibility and impact resistance, and the gloss and the conventional performance meet actual requirements.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a bio-based polyester-modified acrylic secondary dispersion, its preparation method, and its application. Background Technology

[0002] Currently, there are several methods for preparing acrylic acid secondary dispersions in the industry: ① Introducing hydroxyl and carboxyl groups through solution polymerization to form a prepolymer, neutralizing the prepolymer into a salt, and dispersing it with water to obtain an acrylic acid secondary dispersion with a core-shell structure. The core layer is polymerized from hydrophobic monomers, and the shell layer is polymerized from hydrophilic monomers. The raw material monomers of this method are all petroleum-based monomers, which have poor environmental performance. ② Modifying cellulose with double-bonded silanes, grafting the modified cellulose with a mixture of petroleum-based and bio-based monomers to obtain a prepolymer, neutralizing and dispersing the prepolymer with amines to obtain an acrylic acid secondary dispersion. ③ Adding bio-based acrylate monomers to the shell polymer component, and obtaining an acrylic acid emulsion with a soft core and hard shell structure through polymerization. ④ CN116284594 discloses obtaining a bio-based unsaturated oil alcoholysis product through the alcoholysis reaction of unsaturated oils and bio-based glycerol, followed by esterification, condensation, and polymerization reactions with alcohol and acid components, and finally grafting with acrylate monomers to obtain a bio-based alkyd dispersion. The dispersions obtained by this method have high solvent content and poor environmental performance, making them suitable only for single-component waterborne coatings with double bond oxidative crosslinking. Furthermore, they exhibit low fullness and poor resistance to physical / chemical substances, making them unsuitable for two-component polyurethane coatings or amino baking varnishes. ⑤ CN118652382 discloses a method for synthesizing core-shell structured acrylic emulsions from bio-based acrylic monomers via emulsion polymerization. This method is an external emulsification method, resulting in poor mechanical stability. The emulsion contains a large amount of emulsifier, leaving emulsion residue after film formation, severely affecting film durability. Additionally, the resulting acrylic emulsion has an excessively large molecular weight, leading to low gloss and poor fullness in waterborne coatings, making it unsuitable for high-end waterborne coatings.

[0003] In summary, existing technologies for preparing acrylic dispersions present several problems: The preparation of bio-based polyesters by mixing petroleum-based and bio-based monomers involves complex processes such as esterification, transesterification, grafting, and precipitation filtration, resulting in low bio-based content in the polyester; increasing the bio-based content using long-chain bio-based acrylate monomers requires the addition of modified cellulose, leading to low gloss and limited improvement in bio-based content; high-bio-based acrylic emulsions obtained through core-shell emulsion polymerization can achieve a bio-based content of 33.81%, but the gloss and fullness of the coating film are low, and its stability is inferior to that of secondary acrylic dispersions; using bio-based acrylate monomers alone cannot achieve a high bio-based content in secondary acrylic dispersions, while using bio-based polyesters alone cannot meet the performance requirements of the coating film.

[0004] Therefore, there is an urgent need to develop a bio-based polyester-modified acrylic secondary dispersion that can increase the bio-based content while meeting the performance requirements of high performance and high quality of the coating film. Summary of the Invention

[0005] The purpose of this invention is to provide a bio-based polyester-modified acrylic secondary dispersion, its preparation method, and its application, addressing the shortcomings of existing technologies.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing a bio-based polyester-modified acrylic secondary dispersion, comprising the following steps:

[0008] 1) A mixture of bio-based diol, glycerol, bio-based dicarboxylic acid without carbon-carbon double bonds, catalyst, and antioxidant is carried out in the first esterification reaction to obtain an esterification intermediate.

[0009] 2) Add a bio-based dicarboxylic acid containing a carbon-carbon double bond to the esterification intermediate to carry out a second esterification reaction, and obtain a bio-based polyester intermediate;

[0010] 3) Add mixed monomer I dropwise into the bio-based polyester intermediate to obtain the core layer intermediate;

[0011] 4) Add mixed monomer II dropwise to the core layer intermediate to carry out a copolymerization reaction and obtain the core-shell intermediate;

[0012] 5) The core-shell intermediates are neutralized and dispersed sequentially to obtain a bio-based polyester-modified acrylic secondary dispersion.

[0013] Preferably, the bio-based diol comprises one or more of 1,5-pentanediol, bio-based ethylene glycol, and bio-based 1,3-propanediol;

[0014] The bio-based dicarboxylic acid that does not contain carbon-carbon double bonds includes one or more of 2,5-furandicarboxylic acid, bio-based sebacic acid, and tetrahydrofuran-2,5-dicarboxylic acid.

[0015] The bio-based dicarboxylic acid containing carbon-carbon double bonds includes itaconic acid and / or fumaric acid.

[0016] The catalyst is tetrabutyl titanate, and the antioxidant is triphenyl phosphite.

[0017] Preferably, the temperature of the first esterification reaction is 160–180°C, and the time of the first esterification reaction is 4–6 hours.

[0018] The temperature of the second esterification reaction is 180-195℃, and the second esterification reaction is stopped when the acid value of the reaction system is <30mg·KOH / g.

[0019] Preferably, the mass ratio of the bio-based diol, glycerol, bio-based dicarboxylic acid without carbon-carbon double bonds and bio-based dicarboxylic acid with carbon-carbon double bonds is 235-255:9-11:150-175:120-140.

[0020] The mass ratio of the bio-based dicarboxylic acid containing carbon-carbon double bonds to the catalyst is 120–140:1;

[0021] The mass ratio of the bio-based dicarboxylic acid containing carbon-carbon double bonds to the antioxidant is 120–140:1.

[0022] Preferably, the mixed monomer I comprises a bio-based acrylate monomer and a petroleum-based monomer I, wherein the mass ratio of the bio-based acrylate monomer to the petroleum-based monomer I is 25-65:35-75;

[0023] The mixed monomer II comprises bio-based acrylate monomers and petroleum-based monomer II, with a mass ratio of 25–65:35–75 between the bio-based acrylate monomers and the petroleum-based monomer II.

[0024] Preferably, the petroleum-based monomer I comprises one or more of methyl methacrylate, butyl acrylate, styrene, hydroxyethyl methacrylate, and hydroxypropyl methacrylate;

[0025] The petroleum-based monomer II comprises acrylic acid and petroleum-based monomer III, wherein the petroleum-based monomer III comprises one or more of methyl methacrylate, butyl acrylate, styrene, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0026] Preferably, the mass ratio of the bio-based polyester intermediate, mixed monomer I, and mixed monomer II is 42:40-50:25-35.

[0027] Preferably, the dripping rate in step 3) is 2-5 g / s, and the dripping rate in step 4) is 1-3 g / s;

[0028] The copolymerization reaction is carried out at a temperature of 110–130°C for 1–3 hours.

[0029] The present invention also provides a bio-based polyester-modified acrylic secondary dispersion prepared by the aforementioned preparation method.

[0030] The present invention also provides the application of the aforementioned bio-based polyester-modified acrylic secondary dispersion in coatings.

[0031] The beneficial effects of this invention are:

[0032] 1) This invention introduces double bonds into polyester using bio-based itaconic acid / fumaric acid to prepare a bio-based polyester intermediate with carbon-carbon double bonds. Using the bio-based polyester intermediate as a substrate, it first reacts with a mixture of bio-based acrylate monomers and petroleum-based monomers that do not contain acrylic acid to generate a hydrophobic core layer. Then, it reacts with a mixture of bio-based acrylate monomers and petroleum-based monomers that contain acrylic acid to obtain a hydrophilic shell layer, thereby forming a core-shell structured acrylic secondary dispersion. The bio-based polyester-modified acrylic secondary dispersion of this invention has a high solids content, low viscosity, strong emulsifying ability, and good stability. By introducing bio-based elements through both the bio-based polyester intermediate and the bio-based acrylate monomers, the bio-based content is high (>50%), while reducing the amount of petroleum-based monomers used and lowering carbon emissions.

[0033] 2) The coating film formed by the bio-based polyester modified acrylic secondary dispersion of the present invention has significantly improved impact resistance and flexibility compared with petroleum-based raw materials. The appearance quality and conventional properties such as gloss, fullness, and vividness are basically equivalent to those of petroleum-based raw materials, which can meet the actual use requirements. Detailed Implementation

[0034] This invention provides a method for preparing a bio-based polyester-modified acrylic secondary dispersion, comprising the following steps:

[0035] 1) A mixture of bio-based diol, glycerol, bio-based dicarboxylic acid without carbon-carbon double bonds, catalyst, and antioxidant is carried out in the first esterification reaction to obtain an esterification intermediate.

[0036] 2) Add a bio-based dicarboxylic acid containing a carbon-carbon double bond to the esterification intermediate to carry out a second esterification reaction, and obtain a bio-based polyester intermediate;

[0037] 3) Add mixed monomer I dropwise into the bio-based polyester intermediate to obtain the core layer intermediate;

[0038] 4) Add mixed monomer II dropwise to the core layer intermediate to carry out a copolymerization reaction and obtain the core-shell intermediate;

[0039] 5) The core-shell intermediates are neutralized and dispersed sequentially to obtain a bio-based polyester-modified acrylic secondary dispersion.

[0040] In this invention, the bio-based diol preferably comprises one or more of 1,5-pentanediol, bio-based ethylene glycol, and bio-based 1,3-propanediol;

[0041] The bio-based dicarboxylic acid that does not contain carbon-carbon double bonds preferably includes one or more of 2,5-furandicarboxylic acid, bio-based sebacic acid, and tetrahydrofuran-2,5-dicarboxylic acid.

[0042] The bio-based dicarboxylic acid containing carbon-carbon double bonds preferably includes itaconic acid and / or fumaric acid.

[0043] The catalyst is preferably tetrabutyl titanate, and the antioxidant is preferably triphenyl phosphite.

[0044] In this invention, the temperature of the first esterification reaction is preferably 160-180°C, more preferably 165-175°C, and even more preferably 170°C; the time of the first esterification reaction is preferably 4-6 hours, more preferably 4.5-5.5 hours, and even more preferably 5 hours.

[0045] The temperature of the second esterification reaction is preferably 180-195°C, more preferably 185-190°C; the second esterification reaction is preferably stopped when the acid value of the reaction system is <30 mg·KOH / g, more preferably <28 mg·KOH / g, and even more preferably <25 mg·KOH / g.

[0046] In this invention, step 1) the first esterification reaction is preferably carried out under nitrogen protection, and step 2) the second esterification reaction is preferably carried out under nitrogen protection.

[0047] In this invention, after the first esterification reaction is completed in step 1), it is preferable to raise the temperature and reduce the acid value of the reaction system to <15 mg·KOH / g to obtain the esterification intermediate, and more preferably to reduce the acid value to <12 mg·KOH / g.

[0048] The preferred temperature for the heating is 195–205°C, and more preferably 200°C.

[0049] In this invention, after the second esterification reaction in step 2) is completed, it is preferable to add an organic solvent for dilution to obtain a polyester intermediate;

[0050] The organic solvent preferably includes one or more of ethylene glycol butyl ether, propylene glycol butyl ether, diethylene glycol butyl ether, No. 100 solvent oil, n-butyl acetate, and diethylene glycol methyl ether. The mass ratio of the bio-based diacid containing carbon-carbon double bonds to the organic solvent is preferably 120-140:200, more preferably 123-135:200, and even more preferably 132.5:200.

[0051] In this invention, the preferred mass ratio of the bio-based diol, glycerol, bio-based dicarboxylic acid without carbon-carbon double bonds, and bio-based dicarboxylic acid containing carbon-carbon double bonds is 235–255: 9–11: 150–175: 120–140, more preferably 240–250: 9.5–10.5: 155–170: 123–135, and even more preferably 244: 10–10.3: 158–165: 132.5;

[0052] The mass ratio of the bio-based dicarboxylic acid containing carbon-carbon double bonds to the catalyst is preferably 120-140:1, more preferably 123-135:1, and even more preferably 132.5:1;

[0053] The mass ratio of the bio-based dicarboxylic acid containing carbon-carbon double bonds to the antioxidant is preferably 120-140:1, more preferably 123-135:1, and even more preferably 132.5:1.

[0054] In this invention, the mixed monomer I preferably comprises a bio-based acrylate monomer and a petroleum-based monomer I, and the mass ratio of the bio-based acrylate monomer to the petroleum-based monomer I is preferably 25-65:35-75, more preferably 35-55:45-65, and even more preferably 40-50:50-60.

[0055] The mixed monomer II preferably comprises bio-based acrylate monomers and petroleum-based monomer II, and the mass ratio of bio-based acrylate monomers to petroleum-based monomer II is preferably 25-65:35-75, more preferably 35-55:45-65, and even more preferably 40-50:50-60.

[0056] In this invention, the bio-based acrylate monomers preferably include one or more of Evonik VISIOMER Terra C13-MA, Evonik VISIOMER Terra C17.4-MA, Sarbio 6101NS, Sarbio 6104NS, 2-octyl acrylate, Evonik VISIOMER Terra IBOMA, Evonik VISIOMER Terra IBOA, Evonik VISIOMER TerraTHFMA, and Evonik VISIOMER Terra GMMA.

[0057] In this invention, the mixed monomer I preferably further comprises an initiator I, and the mass of the initiator I is preferably 1 to 2% of the mixed monomer I, more preferably 1.5%;

[0058] The mixed monomer II preferably further comprises initiator II, wherein the mass of initiator II is preferably 0.5 to 1.5% of the mixed monomer II;

[0059] The initiator I and initiator II preferably contain one or more of benzoyl peroxide, azobisisobutyronitrile, and dicumyl peroxide.

[0060] In this invention, the petroleum-based monomer I preferably comprises one or more of methyl methacrylate, butyl acrylate, styrene, hydroxyethyl methacrylate, and hydroxypropyl methacrylate;

[0061] The petroleum-based monomer II preferably comprises acrylic acid and petroleum-based monomer III, wherein the petroleum-based monomer III preferably comprises one or more of methyl methacrylate, butyl acrylate, styrene, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0062] In this invention, the mass ratio of the bio-based polyester intermediate, mixed monomer I, and mixed monomer II is preferably 42:40-50:25-35, more preferably 42:43-48:28-33, and even more preferably 42:45:30.

[0063] In this invention, the dripping speed in step 3) is preferably 2-5 g / s, more preferably 3-4 g / s, and even more preferably 3.5 g / s; the dripping speed in step 4) is preferably 1-3 g / s, more preferably 1.5-2.5 g / s, and even more preferably 2 g / s.

[0064] The copolymerization reaction temperature is preferably 110–130°C, more preferably 115–125°C, and even more preferably 120°C; the copolymerization reaction time is preferably 1–3 h, more preferably 1.5–2.5 h, and even more preferably 2 h.

[0065] In this invention, after the addition of mixed monomer II in step 4) is completed, it is preferable to first keep the mixture at a constant temperature and then add the mixed solvent to carry out the copolymerization reaction;

[0066] The mixed solvent preferably comprises benzoyl peroxide and ethylene glycol butyl ether, and the mass ratio of benzoyl peroxide to the bio-based polyester intermediate is preferably 0.01 to 0.1:42, more preferably 0.03 to 0.08:42, and even more preferably 0.05:42;

[0067] The mass ratio of ethylene glycol butyl ether to the bio-based polyester intermediate is preferably 0.5 to 1.5:42, and more preferably 1:42.

[0068] In this invention, the reagent used for neutralization in step 5) is preferably N,N-dimethylethanolamine, and the mass ratio of N,N-dimethylethanolamine to the bio-based polyester intermediate is preferably 5-8:42, more preferably 6-7:42;

[0069] In step 5), the preferred reagent for dispersion is water, and the mass ratio of water to bio-based polyester intermediate is preferably 120-130:42, more preferably 123-128:42.

[0070] The present invention also provides a bio-based polyester-modified acrylic secondary dispersion prepared by the aforementioned preparation method.

[0071] The present invention also provides the application of the aforementioned bio-based polyester-modified acrylic secondary dispersion in coatings.

[0072] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0073] The parts mentioned in the embodiments and comparative examples of the present invention are all parts by mass.

[0074] Example 1

[0075] In this embodiment, mixed monomer I consists of 15 parts of Evonik VISIOMERTerra C13-MA, 9 parts of styrene, 10 parts of methyl methacrylate, 9 parts of hydroxyethyl methacrylate, and 0.5 parts of benzoyl peroxide; mixed monomer II consists of 14 parts of 2-octyl acrylate (purchased from BASF), 6 parts of acrylic acid, 3 parts of methyl methacrylate, 7 parts of hydroxyethyl methacrylate, and 0.21 parts of benzoyl peroxide; and mixed solvent consists of 0.05 parts of benzoyl peroxide and 1 part of ethylene glycol butyl ether.

[0076] Under nitrogen protection, 244 parts of bio-based 1,5-pentanediol, 10.3 parts of glycerol, 171 parts of bio-based 2,5-furandicarboxylic acid, 1 part of tetrabutyl titanate, and 1 part of triphenyl phosphite were mixed and reacted at 170°C for 5 hours. After the reaction, the reaction system was heated to 200°C until the acid value of the reaction system was lower than 15 mg·KOH / g, yielding an esterification intermediate. 132.5 parts of itaconic acid were added to the esterification intermediate, and the reaction was carried out at 190°C until the acid value of the reaction system was lower than 30 mg·KOH / g. Then, 200 parts of ethylene glycol butyl ether were added to obtain a bio-based polyester intermediate, labeled MJZ-1.

[0077] Forty-two parts of bio-based polyester intermediate were added to a reaction vessel equipped with a stirrer, thermometer, serpentine condenser, and constant-pressure dropping funnel. The reaction vessel was heated to 125°C, and mixed monomer I was added dropwise at a rate of 3 g / s, followed by mixed monomer II at a rate of 3 g / s. The mixture was kept at this temperature for 30 min. After the addition was complete, a mixed solvent was added dropwise to the reaction vessel at a rate of 5 g / s. The mixture was kept at this temperature for 1.5 h to carry out the copolymerization reaction, yielding a core-shell intermediate. After the reaction was complete, the reaction vessel was cooled to 120°C, and then six parts of N,N-dimethylethanolamine were added to the reaction vessel for neutralization reaction for 10 min. Finally, 128 parts of deionized water were added to the reaction vessel, and the mixture was dispersed at 500 r / min for 30 min to obtain a bio-based polyester-modified acrylic secondary dispersion.

[0078] The solids content of the bio-based polyester modified acrylic secondary dispersion (labeled as dispersion ①) prepared in this embodiment is 43%, and the bio-based monomer accounts for 50% of the solids content in dispersion ①.

[0079] Example 2

[0080] The difference from Example 1 is that the bio-based polyester intermediate is MJZ-2.

[0081] The preparation method of bio-based polyester intermediate MJZ-2 is as follows: Under nitrogen protection, 244 parts of bio-based 1,5-pentanediol, 10.3 parts of glycerol, 158 parts of bio-based 2,5-furandicarboxylic acid, 1 part of tetrabutyl titanate, and 1 part of triphenyl phosphite were mixed and reacted at 170℃ for 5 hours. After the reaction, the reaction system was heated to 200℃ until the acid value of the reaction system was lower than 15 mg·KOH / g, thus obtaining the esterification intermediate. 123 parts of itaconic acid were added to the esterification intermediate, and the reaction was carried out at 190℃ until the acid value of the reaction system was lower than 30 mg·KOH / g. Then, 200 parts of ethylene glycol butyl ether were added to obtain the bio-based polyester intermediate, labeled as MJZ-2.

[0082] The bio-based polyester modified acrylic secondary dispersion (labeled as dispersion ②) prepared in this embodiment has a solid content of 43%, and the bio-based monomer accounts for 50% of the solid content in dispersion ②.

[0083] Example 3

[0084] The difference from Example 2 is that mixed monomer I consists of 13.4 parts of Evonik VISIOMER Terra C13-MA, 5.6 parts of Evonik VISIOMER Terra GMMA, 12 parts of styrene, 12 parts of methyl methacrylate and 0.5 parts of benzoyl peroxide, mixed monomer II consists of 11.5 parts of 2-octyl acrylate (purchased from BASF), 4.5 parts of Evonik VISIOMER Terra GMMA, 6 parts of acrylic acid, 8 parts of methyl methacrylate and 0.21 parts of benzoyl peroxide, and mixed solvent consists of 0.05 parts of benzoyl peroxide and 1 part of ethylene glycol butyl ether.

[0085] The solids content of the bio-based polyester modified acrylic secondary dispersion (labeled as dispersion ③) prepared in this embodiment is 43%, and the bio-based monomer accounts for 74% of the solids content in dispersion ③.

[0086] Example 4

[0087] The difference from Example 3 is that the bio-based polyester intermediate is MJZ-1. Mixed monomer I consists of 12 parts Evonik VISIOMER Terra C13-MA, 7 parts Evonik VISIOMER Terra GMMA, 12 parts styrene, 12 parts methyl methacrylate, and 0.5 parts benzoyl peroxide. Mixed monomer II consists of 13 parts 2-octyl acrylate (purchased from BASF), 6 parts Evonik VISIOMER Terra GMMA, 7 parts acrylic acid, 4 parts methyl methacrylate, and 0.21 parts benzoyl peroxide. The mixed solvent consists of 0.05 parts benzoyl peroxide and 1 part ethylene glycol butyl ether. The preparation method of the bio-based polyester intermediate MJZ-1 is the same as in Example 1.

[0088] The solids content of the bio-based polyester modified acrylic secondary dispersion (labeled as dispersion ④) prepared in this embodiment is 43%, and the bio-based monomer accounts for 74% of the solids content in dispersion ④.

[0089] Example 5

[0090] The difference from Example 1 is that the bio-based polyester intermediate is MJZ-4.

[0091] The preparation method of bio-based polyester intermediate MJZ-4 is as follows: Under nitrogen protection, 252 parts of bio-based 1,3-propanediol, 9.5 parts of glycerol, 175 parts of bio-based tetrahydrofuran-2,5-dicarboxylic acid, 1 part of tetrabutyl titanate, and 1 part of triphenyl phosphite were mixed and reacted at 180℃ for 4 hours. After the reaction, the reaction system was heated to 200℃ until the acid value of the reaction system was lower than 15 mg·KOH / g, thus obtaining the esterification intermediate. 123 parts of fumaric acid were added to the esterification intermediate, and the reaction was carried out at 180℃ until the acid value of the reaction system was lower than 30 mg·KOH / g. Then, 200 parts of ethylene glycol butyl ether were added to obtain the bio-based polyester intermediate, labeled as MJZ-4.

[0092] The bio-based polyester modified acrylic secondary dispersion (labeled as dispersion ⑤) prepared in this embodiment has a solid content of 43%, and the bio-based monomer accounts for 61.4% of the solid content in dispersion ⑤.

[0093] Comparative Example 1

[0094] In this comparative example, mixed monomer I consists of 12 parts styrene, 12 parts methyl methacrylate, 10 parts lauryl acrylate, 9 parts hydroxyethyl methacrylate and 0.5 parts benzoyl peroxide, mixed monomer II consists of 6 parts acrylic acid, 3 parts methyl methacrylate, 14 parts butyl acrylate, 7 parts hydroxyethyl methacrylate and 0.21 parts benzoyl peroxide, and mixed solvent consists of 0.05 parts benzoyl peroxide and 1 part ethylene glycol butyl ether.

[0095] Under nitrogen protection, 244.33 parts of diethylene glycol, 15 parts of trimethylolpropane, 182 parts of isophthalic acid, 1 part of butyl titanate, and 1 part of triphenyl phosphite were mixed and reacted at 170°C for 5 hours. After the reaction, the reaction system was heated to 200°C until the acid value of the reaction system was lower than 15 mg·KOH / g, yielding an esterification intermediate. 100 parts of maleic anhydride were added to the esterification intermediate, and the reaction was carried out at 190°C until the acid value of the reaction system was lower than 30 mg·KOH / g. Then, 200 parts of ethylene glycol butyl ether were added to obtain a polyester intermediate, labeled MJZ-3.

[0096] Forty-two parts of polyester intermediate were added to a reaction vessel equipped with a stirrer, thermometer, serpentine condenser, and constant-pressure dropping funnel. The reaction vessel was heated to 125°C, and mixed monomer I was added dropwise at a rate of 3 g / s, followed by mixed monomer II at a rate of 2 g / s. The mixture was kept at this temperature for 30 min. After the addition was complete, a mixed solvent was added dropwise to the reaction vessel at a rate of 5 g / s. The mixture was kept at this temperature for 1.5 h to carry out the copolymerization reaction, yielding a core-shell intermediate. After the reaction was complete, the reaction vessel was cooled to 120°C, and then six parts of N,N-dimethylethanolamine were added to the reaction vessel for neutralization reaction for 10 min. Finally, 128 parts of deionized water were added to the reaction vessel, and the mixture was dispersed at 500 r / min for 30 min to obtain a secondary dispersion of acrylic acid.

[0097] The acrylic acid secondary dispersion (labeled as dispersion ⑥) prepared in this comparative example has a solid content of 43%, and the bio-based monomer accounts for 0% of the solid content in dispersion ⑥.

[0098] Comparative Example 2

[0099] The difference from Example 4 is that the bio-based polyester intermediate MJZ-1 is replaced with polyester intermediate MJZ-3, and the preparation method of polyester intermediate MJZ-3 is the same as that of Comparative Example 1.

[0100] The acrylic acid secondary dispersion (labeled as dispersion ⑦) prepared in this comparative example has a solid content of 43%, and the bio-based monomer accounts for 24% of the solid content in dispersion ⑦.

[0101] Comparative Example 3

[0102] The difference from Example 1 is that mixed monomer I consists of 7 parts Evonik VISIOMER Terra C13-MA, 13 parts styrene, 13 parts methyl methacrylate, 10 parts hydroxyethyl methacrylate and 0.5 parts benzoyl peroxide, mixed monomer II consists of 6 parts 2-octyl acrylate (purchased from BASF), 3 parts acrylic acid, 12 parts methyl methacrylate, 9 parts hydroxyethyl methacrylate and 0.21 parts benzoyl peroxide, and mixed solvent consists of 0.05 parts benzoyl peroxide and 4 parts ethylene glycol butyl ether.

[0103] The acrylic acid secondary dispersion (labeled as dispersion ⑧) prepared in this comparative example had a solid content of 45.2%, and the bio-based monomers in dispersion ⑧ accounted for 17.8% of the solid content by mass.

[0104] Comparative Example 4

[0105] The difference from Example 1 is that mixed monomer I consists of 32 parts of Evonik VISIOMER Terra C13-MA, 3 parts of styrene, 4 parts of methyl methacrylate, 4 parts of hydroxyethyl methacrylate and 0.5 parts of benzoyl peroxide, mixed monomer II consists of 23 parts of 2-octyl acrylate (purchased from BASF), 3 parts of acrylic acid, 2 parts of methyl methacrylate, 2 parts of hydroxyethyl methacrylate and 0.21 parts of benzoyl peroxide, and mixed solvent consists of 0.05 parts of benzoyl peroxide and 1 part of ethylene glycol butyl ether.

[0106] The acrylic acid secondary dispersion (labeled as dispersion ⑨) prepared in this comparative example had a solid content of 43%, and the bio-based monomers in dispersion ⑨ accounted for 75.3% of the solid content by mass.

[0107] The formulation of the paint pigment is shown in Table 1.

[0108] Table 1 Formulation of Coating Pigments

[0109] formula Paint Color Paste I formula Paint Color Paste II Dispersant BYK-190 9g Red Pigment F3RK 30g Defoamer TEGO-830 0.5g Dispersant BYK-190 6g talcum powder 6g Defoamer TEGO-830 0.5g Precipitated barium sulfate 6g Deionized water 63.5g mica powder 6g —— —— carbon black 6g —— —— Deionized water 4.3g —— —— total 37.8g total 100g

[0110] Application Example 1

[0111] The coating in this application example consists of component A and component B, with a mass ratio of component A to component B of 5.1:1.

[0112] Component A consists of 55g dispersion ①, 37.8g color paste I, 2.5g ethylene glycol butyl ether, 2.5g dipropylene glycol butyl ether, 0.2g wetting agent TEGO-4100, 0.2g wetting agent TEGO-270, 0.3g surfactant Surfynol AD-01, 0.3g leveling agent BYK-381, 0.2g thickener Coapur XS-83, and 1g dimethylethanolamine (mass concentration of 10%).

[0113] Component B is the isocyanate curing agent AQUAPU-285 (purchased from Jiangsu Fuqisen New Material Co., Ltd., with a solid content of 100% and an NCO / OH ratio of 1.5).

[0114] The tinplate was sanded with 400-grit sandpaper and wiped clean with anhydrous ethanol. At 25°C and RH 48%, the coating was sprayed onto the tinplate surface using air spraying (1.3mm nozzle diameter, 4MPa air pressure). After spraying, the coating was allowed to level at room temperature for 20 minutes, then baked at 70°C for 4 hours to obtain a 40μm thick paint film.

[0115] Application Example 2

[0116] Replace dispersion ① in Application Example 1 with dispersion ②, and keep everything else the same as in Application Example 1.

[0117] Application Example 3

[0118] Replace dispersion ① in Application Example 1 with dispersion ③, and keep everything else the same as in Application Example 1.

[0119] Application Example 4

[0120] Replace dispersion ① in Application Example 1 with dispersion ④, and keep everything else the same as in Application Example 1.

[0121] Application Example 5

[0122] Replace dispersion ① in Application Example 1 with dispersion ⑤, and keep everything else the same as in Application Example 1.

[0123] Application Example 6

[0124] The coating in this application example consists of 60g dispersion ①, 15g color paste II, 8.5g amino resin 325, 4g ethylene glycol butyl ether, 4g dipropylene glycol methyl ether, 0.3g defoamer DF-110D, 0.3g wetting agent TEGO-270, 0.3g leveling agent BYK-381, 0.3g thickener Coapur XS-83, 0.3g dimethyl ethanolamine (mass concentration of 10%), and 7g deionized water.

[0125] The tinplate was sanded with 400-grit sandpaper and wiped clean with anhydrous ethanol. At 25°C and RH 48%, the coating was sprayed onto the tinplate surface using air spraying (1.3mm nozzle diameter, 4MPa air pressure). After spraying, the coating was allowed to level at room temperature for 5 minutes, then pre-baked at 80°C for 15 minutes, followed by baking at 180°C for 20 minutes to obtain a 35μm thick paint film.

[0126] Application Example 7

[0127] Replace dispersion ① in Application Example 6 with dispersion ②, and everything else is the same as in Application Example 6.

[0128] Application Example 8

[0129] Replace dispersion ① in Application Example 6 with dispersion ③, and everything else is the same as in Application Example 6.

[0130] Application Example 9

[0131] Replace dispersion ① in Application Example 6 with dispersion ④, and everything else is the same as in Application Example 6.

[0132] Application Example 10

[0133] Replace dispersion ① in Application Example 6 with dispersion ⑤, and keep the rest the same as in Application Example 6.

[0134] Application Comparative Example 1

[0135] Replace dispersion ① in Application Example 1 with dispersion ⑥, modify the mass ratio of component A to component B to 10.2:3, and keep the rest the same as in Application Example 1.

[0136] Application Comparative Example 2

[0137] Replace dispersion ① in Application Example 1 with dispersion ⑦, modify the mass ratio of component A to component B to 10.2:3, and keep the rest the same as in Application Example 1.

[0138] Application Comparative Example 3

[0139] Replace dispersion ① in Application Example 1 with dispersion ⑧, modify the mass ratio of component A to component B to 10.2:3, and keep the rest the same as in Application Example 1.

[0140] Application Comparative Example 4

[0141] Replace dispersion ① in Application Example 1 with dispersion ⑨, modify the mass ratio of component A to component B to 10.2:3, and keep the rest the same as in Application Example 1.

[0142] Application Comparative Example 5

[0143] Replace dispersion ① in Application Example 6 with dispersion ⑥, and keep the rest the same as in Application Example 6.

[0144] Application Comparative Example 6

[0145] Replace dispersion ① in Application Example 6 with dispersion ⑦, and everything else is the same as in Application Example 6.

[0146] Application Comparative Example 7

[0147] Replace dispersion ① in Application Example 6 with dispersion ⑧, and everything else is the same as in Application Example 6.

[0148] Application Comparative Example 8

[0149] Replace dispersion ① in Application Example 6 with dispersion ⑨, and keep the rest the same as in Application Example 6.

[0150] Performance tests were conducted on the paint films corresponding to use cases 1-10 and comparative examples 1-8, respectively. Gloss was tested using a gloss meter; hardness was tested using the pencil hardness test; adhesion was tested using the cross-cut test; impact resistance was tested according to GB / T 1732-2020; flexibility was tested using the shaft bending test according to GB / T 1731-2020; resistance to 5% NaOH solution was tested according to GB / T 9274-1988; resistance to 5% H2SO4 solution was tested according to GB 1763-1979; and water resistance was tested according to GB / T 1733-1993. The test results are shown in Tables 2 and 3.

[0151] Table 2. Results of paint film performance tests (gloss, adhesion, impact resistance, flexibility)

[0152]

[0153] Table 3. Test results of paint film performance (hardness, resistance to 5% NaOH, resistance to 5% H2SO4, water resistance)

[0154]

[0155] As can be seen from Tables 2 and 3, the bio-based polyester modified acrylic secondary dispersion of the present invention improves impact resistance and flexibility while increasing the content of bio-based monomers. Its appearance quality, such as gloss, fullness, and reflectivity, is comparable to that of the coating film prepared from petroleum-based raw materials. At the same time, the conventional properties of the coating film can meet the requirements for use.

[0156] As can be seen from the above embodiments, the present invention provides a bio-based polyester modified acrylic secondary dispersion, which is prepared by copolymerization of a bio-based polyester intermediate with a mixture of bio-based monomers and petroleum-based monomers. The paint film prepared by the bio-based polyester modified acrylic secondary dispersion of the present invention has good gloss, fullness, vividness and flexibility, and other conventional properties can meet the requirements of use.

[0157] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a bio-based polyester-modified acrylic secondary dispersion, characterized in that, It includes the following steps: 1) A mixture of bio-based diol, glycerol, bio-based dicarboxylic acid without carbon-carbon double bonds, catalyst, and antioxidant is carried out in the first esterification reaction to obtain an esterification intermediate. 2) Add a bio-based dicarboxylic acid containing a carbon-carbon double bond to the esterification intermediate to carry out a second esterification reaction, and obtain a bio-based polyester intermediate; 3) Add mixed monomer I dropwise into the bio-based polyester intermediate to obtain the core layer intermediate; 4) Add mixed monomer II dropwise to the core layer intermediate to carry out a copolymerization reaction and obtain the core-shell intermediate; 5) The core-shell intermediates are neutralized and dispersed sequentially to obtain a bio-based polyester-modified acrylic secondary dispersion.

2. The preparation method according to claim 1, characterized in that, The bio-based diol comprises one or more of 1,5-pentanediol, bio-based ethylene glycol, and bio-based 1,3-propanediol. The bio-based dicarboxylic acid that does not contain carbon-carbon double bonds includes one or more of 2,5-furandicarboxylic acid, bio-based sebacic acid, and tetrahydrofuran-2,5-dicarboxylic acid. The bio-based dicarboxylic acid containing carbon-carbon double bonds includes itaconic acid and / or fumaric acid. The catalyst is tetrabutyl titanate, and the antioxidant is triphenyl phosphite.

3. The preparation method according to claim 1 or 2, characterized in that, The temperature of the first esterification reaction is 160–180°C, and the time of the first esterification reaction is 4–6 hours; The temperature of the second esterification reaction is 180-195℃, and the second esterification reaction is stopped when the acid value of the reaction system is <30mg·KOH / g.

4. The preparation method according to claim 3, characterized in that, The mass ratio of the bio-based diol, glycerol, bio-based dicarboxylic acid without carbon-carbon double bonds and bio-based dicarboxylic acid with carbon-carbon double bonds is 235-255:9-11:150-175:120-140. The mass ratio of the bio-based dicarboxylic acid containing carbon-carbon double bonds to the catalyst is 120–140:1; The mass ratio of the bio-based dicarboxylic acid containing carbon-carbon double bonds to the antioxidant is 120–140:

1.

5. The preparation method according to claim 4, characterized in that, The mixed monomer I comprises a bio-based acrylate monomer and a petroleum-based monomer I, with a mass ratio of 25-65:35-75 between the bio-based acrylate monomer and the petroleum-based monomer I. The mixed monomer II comprises bio-based acrylate monomers and petroleum-based monomer II, with a mass ratio of 25–65:35–75 between the bio-based acrylate monomers and the petroleum-based monomer II.

6. The preparation method according to claim 5, characterized in that, The petroleum-based monomer I comprises one or more of methyl methacrylate, butyl acrylate, styrene, hydroxyethyl methacrylate, and hydroxypropyl methacrylate; The petroleum-based monomer II comprises acrylic acid and petroleum-based monomer III, wherein the petroleum-based monomer III comprises one or more of methyl methacrylate, butyl acrylate, styrene, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

7. The preparation method according to claim 5 or 6, characterized in that, The mass ratio of the bio-based polyester intermediate, mixed monomer I, and mixed monomer II is 42:40-50:25-35.

8. The preparation method according to claim 7, characterized in that, The dripping rate in step 3) is 2-5 g / s, and the dripping rate in step 4) is 1-3 g / s; The copolymerization reaction is carried out at a temperature of 110–130°C for 1–3 hours.

9. The bio-based polyester-modified acrylic secondary dispersion prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the bio-based polyester-modified acrylic secondary dispersion of claim 9 in coatings.

Images