Cationic light-cured bio-based polyurethane dispersion as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of coatings, and discloses a cationic photocuring bio-based polyurethane dispersoid and a preparation method and application thereof.The preparation method comprises the steps that a macromolecular hydrophilic amine chain extender is prepared from a bio-based material, a polyurethane prepolymer and the macromolecular hydrophilic amine chain extender are pre-dispersed and then mixed for a chain extension reaction, and the cationic photocuring bio-based polyurethane dispersoid is obtained. The preparation method comprises the following steps: preparing a cationic light-cured bio-based polyurethane dispersion, adding deionized water to complete dispersion to obtain the cationic light-cured bio-based polyurethane dispersion with hydrophobic epoxy resin as a core and hydrophilic polyurethane as a shell. A paint film of the prepared paint has the advantages of good flexibility, good water resistance and chemical resistance, excellent adhesion to multiple substrates and the like, and can be applied to high-grade wood paints, automobile paints, metal anticorrosive paints and other industrial protective paints.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and particularly relates to a cationic light-cured bio-based polyurethane dispersion and a preparation method and application thereof. Background Art

[0002] Water-based wood coatings are divided into single-component and two-component water-based coatings and emerging water-based light-curing coatings. At present, most coatings except for interior and exterior wall coatings are still solvent-based coatings, containing more than 50% organic solvents. These solvents will volatilize into the atmosphere during the construction process, polluting the environment and damaging human health. In addition, organic solvents themselves will bring potential safety hazards. Therefore, water-based coatings are the development trend.

[0003] Waterborne coatings mainly include waterborne one-component coatings, waterborne two-component coatings, and waterborne photocurable coatings that have developed rapidly in recent years. The film properties of one-component waterborne coatings, such as water resistance, chemical resistance and hardness, are quite different from those of solvent-based coatings, which seriously limits the promotion and application of waterborne coatings. The mechanical properties, water resistance and chemical resistance of two-component waterborne coatings are close to those of solvent-based coatings, but due to the problem of activation period, they are not suitable for reciprocating mechanical spraying and electrostatic spraying, and their drying speed is slow, which affects the construction efficiency. The film mechanical properties, water resistance and chemical resistance of waterborne photocurable coatings are better than those of solvent-based products. They are single-component packaging, ready to use after opening the barrel, and have no activation period. They are suitable for various mechanical spraying, and they can be packaged offline after drying for 0.5 to 2 hours after construction and curing with a UV curing machine. In the future, waterborne photocurable coatings will replace two-component waterborne coatings and become the first choice for high-end waterborne coatings. At present, there is a lack of photocurable bio-based resins for waterborne photocurable coatings on the market.

[0004] Therefore, there is an urgent need to provide a photocurable bio-based resin for developing water-based photocurable coatings. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a cationic photocurable bio-based polyurethane dispersion and a preparation method and application thereof. The cationic photocurable bio-based polyurethane dispersion provided by the present invention can make the epoxy resin be wrapped by the polyurethane prepolymer through a pre-dispersion process, so as to avoid it from contacting and reacting with the macromolecular amine chain extender, thereby ensuring dispersion and storage stability. The prepared paint film has the advantages of good flexibility, good water resistance and chemical resistance, excellent adhesion to various substrates, etc., and can be applied to high-end wood coatings, automotive coatings, metal anti-corrosion coatings and other industrial protective coatings.

[0006] The inventive concept of the present invention is as follows: the present invention uses bio-based materials to prepare a macromolecular hydrophilic amine chain extender, pre-disperses a polyurethane prepolymer (obtained by mixing a macromolecular diol, a mixture C1, an isocyanate monomer, a small molecular diol chain extender and an epoxy resin in step S4) and a macromolecular hydrophilic amine chain extender, respectively, and then mixes them for chain extension reaction, and then adds deionized water to complete the dispersion, thereby obtaining a cationic light-cured bio-based polyurethane dispersion with a hydrophobic epoxy resin as a core and a hydrophilic polyurethane as a shell (the polyurethane prepolymer is considered to have formed a core-shell structure during pre-dispersion, because the epoxy resin is hydrophobic, and the polyurethane prepolymer is hydrophilic, therefore, in the process of adding water for dispersion, the hydrophilic part will wrap the hydrophobic part like an emulsifier). The pre-dispersion process of the preparation method can make the epoxy resin wrapped by the polyurethane prepolymer, so as to prevent it from contacting and reacting with the macromolecular amine chain extender, thereby ensuring dispersion and storage stability. Through pre-dispersion, the polyurethane prepolymer wraps the epoxy resin, which plays a role in isolating the epoxy resin and the amine. When the pre-dispersion liquid of the polyurethane prepolymer and the pre-dispersion liquid of the macromolecular amine chain extender are mixed, the macromolecular amine chain extender can basically react only with the polyurethane prepolymer in the shell layer and does not react with the epoxy resin, thereby preserving the epoxy group. After the reaction, the macromolecular amine chain extender and the polyurethane prepolymer wrapped on the surface of the epoxy resin form a shell layer together, and the epoxy resin is the core.

[0007] The invention also provides a cationic light-cured bio-based polyurethane dispersion.

[0008] The invention also provides a water-based bio-based photocurable coating.

[0009] The present invention also provides an application of a water-based bio-based light-curing coating in the fields of wood product preparation, automobile manufacturing or metal product corrosion protection.

[0010] The first aspect of the present invention provides a cationic light-curable bio-based polyurethane dispersion, the preparation method of which comprises the following steps:

[0011] S1. The diisocyanate and hydroxy vinyl ether are mixed and reacted to obtain a prepolymer A1 containing a vinyl group and an isocyanate group;

[0012] S2. After the bio-based material and the hydrophilic modifier are mixed and reacted, acrylic monomer, diamine and neutralizing agent are added, mixed and dispersed in water to obtain a macromolecular hydrophilic amine chain extender dispersion B1;

[0013] S3. The hydrophilic chain extender and the neutralizing agent are mixed to form a mixture C1;

[0014] S4. The macromolecular diol, the mixture C1, the isocyanate monomer, the small molecule diol chain extender and the epoxy resin are mixed and reacted, dispersed with water, and then mixed with the macromolecular hydrophilic amine chain extender dispersion B1 and dispersed with water;

[0015] The raw materials for preparing the bio-based material include vegetable oil containing more than three epoxy groups;

[0016] The hydrophilic modifier includes a monomer containing a secondary amino group and a sulfonic acid group;

[0017] The epoxy resin includes an epoxy resin containing three or more epoxy groups.

[0018] The preferred bio-based material in the present invention contains more than three epoxy groups, which can ensure that each bio-based material can be grafted with a hydrophilic modifier, no less than one double bond-containing monomer and two diamines.

[0019] In the present invention, three or more epoxy groups ensure that at least one epoxy group reacts with a hydrophilic modifier, two epoxy groups react with diamines, and one epoxy group reacts with a carboxyl group of acrylic acid. The secondary amino group can ensure that one hydrophilic modifier reacts only with one epoxy vegetable oil. The hydrophilic modifier (a monomer containing a secondary amino group and a sulfonic acid group) provides hydrophilicity through the sulfonic acid group. Generally, carboxyl groups and sulfonic acid groups are used to provide hydrophilicity in polyurethane synthesis. However, since vegetable oils contain epoxy groups, carboxyl groups will react with epoxy groups. Therefore, hydrophilic modifiers containing carboxyl groups cannot be used here.

[0020] In some embodiments of the present invention, the preparation method comprises the following steps:

[0021] S1. In parts by mass, 10 to 15 parts of diisocyanate are heated to 40 to 60°C and then 6 to 12 parts of hydroxy vinyl ether are added dropwise, and the reaction is continued to obtain a prepolymer A1 containing a vinyl group and an isocyanate group;

[0022] S2. In terms of mass fractions, 15 to 25 parts of bio-based materials are heated to 70 to 90°C, 3 to 5 parts of hydrophilic modifiers are added, reacted, heated to 130 to 150°C, 3 to 4.5 parts of acrylic acid monomers are added dropwise, stirred and kept warm after the addition is complete, cooled to 70 to 80°C, 17 to 25 parts of A1 are added, stirred and kept warm, 2 to 6 parts of diamine are added, stirred and kept warm, 1.0 to 2.0 parts of neutralizer are added, stirred, 50 to 55 parts of deionized water are added, and dispersed to obtain a macromolecular hydrophilic amine chain extender dispersion B1;

[0023] S3. In parts by mass, 4 to 6 parts of a hydrophilic chain extender and 1 to 2 parts of a neutralizing agent are mixed to form a mixture C1;

[0024] S4. In terms of mass fractions, 10 to 20 parts of macromolecular diol and mixture C1 are mixed and heated to 70 to 80°C, 25 to 36 parts of diisocyanate monomers are added after stabilization, 8 to 16 parts of small molecule diol chain extenders are added after the reaction, the reaction is continued, the temperature is lowered to 40 to 50°C, 10 to 25 parts of epoxy resin are added, and the mixture is stirred. 65 to 75 parts of deionized water are added and dispersed, 100 to 115 parts of macromolecular hydrophilic amine chain extender dispersion B1 are added, the temperature is raised to 50 to 60°C, the mixture is dispersed and reacted, 75 to 85 parts of deionized water are added and stirred to obtain the cationic light-curable bio-based polyurethane dispersion.

[0025] In some embodiments of the present invention, the preparation method comprises the following steps:

[0026] S1. When 10 to 15 parts of diisocyanate are heated to 40 to 60°C, 6 to 12 parts of hydroxy vinyl ether are added dropwise at a constant pressure within 10 to 30 minutes, and the reaction is continued for 0.5 to 1 hour to obtain a prepolymer A1 containing a vinyl group and an isocyanate group;

[0027] S2. In terms of mass fractions, 15 to 25 parts of bio-based materials are heated to 70 to 90 ° C, 3 to 5 parts of hydrophilic modifiers are added, the reaction is carried out for 1 to 1.5 hours, the temperature is raised to 130 to 150 ° C, 3 to 4.5 parts of acrylic acid monomers are dripped at a constant pressure within 5 to 15 minutes, and after dripping, they are stirred and kept warm for 20 to 30 minutes, cooled to 70 to 80 ° C, 17 to 25 parts of A1 are added, stirred and kept warm for 45 to 60 minutes, 2 to 6 parts of diamine are added, stirred and kept warm for 20 to 30 minutes, 1.0 to 2.0 parts of neutralizer are added, stirred for 3 to 5 minutes, 50 to 55 parts of deionized water are added, and dispersed for 3 to 5 minutes to obtain a macromolecular hydrophilic amine chain extender dispersion B1;

[0028] S3. In parts by mass, 4 to 6 parts of a hydrophilic chain extender and 1 to 2 parts of a neutralizing agent are mixed to form a mixture C1;

[0029] S4. In terms of mass fractions, 10 to 20 parts of macromolecular diol and mixture C1 are mixed and heated to 70 to 80°C, stabilized for 5 to 15 minutes, 25 to 36 parts of diisocyanate monomer are added, reacted for 25 to 60 minutes, 8 to 16 parts of small molecule diol chain extender are added, the reaction is continued for 25 to 60 minutes, the temperature is reduced to 40 to 50°C, 10 to 25 parts of epoxy resin are added, stirred for 5 to 15 minutes, 65 to 75 parts of deionized water are added, dispersed for 5 to 10 minutes, 100 to 115 parts of macromolecular hydrophilic amine chain extender dispersion B1 are added, the temperature is increased to 50 to 60°C, dispersed and reacted for 15 to 25 minutes, 75 to 85 parts of deionized water are added, stirred for 10 to 20 minutes, the temperature is reduced to 40°C, and the cationic light-cured bio-based polyurethane dispersion is obtained.

[0030] In some embodiments of the present invention, the diisocyanate monomer includes at least one of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

[0031] In some embodiments of the present invention, the hydroxy vinyl ether includes at least one of 4-hydroxybutyl vinyl ether, triethylene glycol divinyl ether, and cyclohexyl-1,4-dimethanol monovinyl ether.

[0032] In some embodiments of the present invention, the bio-based material includes special epoxy soybean oil GreenSoft D, special epoxy soybean oil GreenSoft H and epoxy linseed oil ELO 9-5 TM At least one of the .

[0033] In some embodiments of the present invention, the hydrophilic modifier includes at least one of cyclohexylaminoethanesulfonic acid CHES, cyclohexylaminopropanesulfonic acid CAPS and cyclohexylaminobutanesulfonic acid CABS.

[0034] In some embodiments of the present invention, the acrylic acid monomer includes at least one of acrylic acid AA and methacrylic acid MAA.

[0035] In some embodiments of the present invention, the diamine includes at least one of ethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine and isophoronediamine.

[0036] In some embodiments of the present invention, the neutralizing agent includes at least one of triethylamine TEA, N,N-dimethylethanolamine DMEA and N,N-dimethylcyclohexylamine DMCHA.

[0037] In some embodiments of the present invention, the macromolecular diol is a diol with a molecular weight of 1000 to 2000.

[0038] In some embodiments of the present invention, the macromolecular diol includes at least one of polyether diol N220, polybutylene adipate diol PBA2000 and polycarbonate diol PCDL2000.

[0039] In some embodiments of the present invention, the small molecule diol chain extender includes at least one of 1,4-butanediol BDO, 2,4-diethyl-1,5-pentanediol PD-9, ethyl butyl propanediol BEPD, 1,6-hexanediol HDO and neopentyl glycol NPG.

[0040] In some embodiments of the present invention, the hydrophilic chain extender includes at least one of dimethylol propionic acid DMPA, dimethylol butyric acid DMBA and Ymer N120.

[0041] Ymer N120 is a nonionic hydrophilic chain extender with a molecular weight of about 1000.

[0042] In some embodiments of the present invention, the epoxy resin includes at least one of tetraglycidyl diaminodimethylenebenzene MF-4101, diglycidyl 4,5-epoxytetrahydrophthalate MF-3286, and triglycidyl-p-aminophenol MF-3102.

[0043] The invention uses bio-based materials to prepare a macromolecular hydrophilic amine chain extender, pre-disperses a polyurethane prepolymer and a macromolecular hydrophilic amine chain extender respectively, mixes them for chain extension reaction, and then adds deionized water to complete dispersion, thereby obtaining a cationic light-cured bio-based polyurethane dispersion with a hydrophobic epoxy resin as a core and a hydrophilic polyurethane as a shell. The polyurethane prepolymer pre-disperses in the preparation method, so that the epoxy resin can be wrapped by the hydrophilic polyurethane prepolymer. At the same time, since the macromolecular amine chain extender is also pre-dispersed, when the two are mixed, the macromolecular amine chain extender only contacts and reacts with the polyurethane prepolymer, and avoids the macromolecular amine chain extender from contacting and reacting, thereby ensuring dispersion and storage stability.

[0044] A second aspect of the present invention provides a cationic photocurable bio-based polyurethane dispersion, wherein the bio-based content of the cationic photocurable bio-based polyurethane dispersion is ≥ 12%.

[0045] In some embodiments of the present invention, the cationic light-curable bio-based polyurethane dispersion has a pH of 6 to 7, a particle size of less than 110 nm, and a solid content of 38 to 41%.

[0046] The cationic photocurable bio-based polyurethane dispersion prepared by the present invention has the characteristics of large molecular weight, high bio-based content, good storage stability, good appearance, high reaction activity, good tolerance, excellent adhesion to various substrates, etc.; and the preparation method has the advantages of simple operation, easy control and low cost, and can prepare cationic photocurable bio-based polyurethane dispersion in batches.

[0047] The third aspect of the present invention provides a water-based bio-based photocurable coating, the preparation raw materials of which include cationic photocurable bio-based polyurethane dispersion.

[0048] In some embodiments of the present invention, the water-based bio-based photocurable coating comprises the following raw materials in parts by weight:

[0049]

[0050]

[0051] In some embodiments of the present invention, the auxiliary agent includes a film-forming auxiliary agent, a defoaming agent, a thickener and a wetting agent.

[0052] In some embodiments of the present invention, the water-based bio-based photocurable coating comprises the following raw materials in parts by weight:

[0053]

[0054] In the water-based bio-based photocurable coating of the present invention, since the groups that can participate in photocuring of the cationic photocurable bio-based polyurethane dispersion of the present invention include vinyl ether double bonds, acryloyloxy double bonds and epoxy groups, the free radical photoinitiator can initiate the polymerization of acryloyloxy double bonds, and the cationic photoinitiator can initiate the polymerization of vinyl ether double bonds and epoxy groups. When the two types of photoinitiators are added at the same time, the above groups can copolymerize. The polymerization shrinkage rate initiated by the free radical photoinitiator is large, the oxygen inhibition is obvious, and the adhesion to many substrates is poor, while the polymerization shrinkage rate initiated by the cationic photoinitiator is small, there is no oxygen inhibition, and its epoxy group has excellent adhesion to a variety of substrates, which can fully make up for the shortcomings of free radical photocuring. Therefore, the paint film of the water-based photocurable bio-based coating has the advantages of high gloss, high transparency, excellent water resistance and chemical resistance, high crosslinking density, high flexibility and excellent adhesion to a variety of substrates, and can be applied to high-end wood coatings, automotive coatings, metal anticorrosive coatings and other industrial protective coatings.

[0055] In some embodiments of the present invention, the free radical photoinitiator includes at least one of Darocur 1173, Irgacure 2959, Irgacure 500, Lucirin TPO-L, and Irgacure 819-DW.

[0056] In some embodiments of the present invention, the cationic photoinitiator includes at least one of HRcure-9387, HRcure-9392, HRcure-9388, HRcure-262, HRcure-261, HRcure-6992, HRcure-6976 and Omnirad250.

[0057] In some embodiments of the present invention, the film-forming aid includes at least one of propylene glycol methyl ether PM, propylene glycol butyl ether PnB, dipropylene glycol methyl ether and DPM dipropylene glycol butyl ether DPnB.

[0058] In some embodiments of the present invention, the defoamer includes at least one of the polyether siloxane copolymer defoamers TEGO-800, TEGO-805, TEGO-815, TEGO-825 and the modified polysiloxane copolymer solutions BYK-019 and BYK-020.

[0059] In some embodiments of the present invention, the thickener includes at least one of a nonionic polyurethane associative thickener RM-8W, a hydrophobically modified alkali-swellable associative thickener TT-935, an alkali-swellable non-associative thickener ASE-60, and nonionic associative thickeners TEGO ViscoPlus 3000, TEGO ViscoPlus 3030, and TEGO ViscoPlus 3060.

[0060] In some embodiments of the present invention, the wetting agent includes at least one of polyether siloxane copolymer TEGO-245, nonionic organic surfactant TEGO-500, and polyether modified polysiloxane solution BYK-346.

[0061] In some embodiments of the present invention, the method for preparing the water-based photocurable bio-based coating comprises the following steps:

[0062] The water and the film-forming aid are premixed and added to the cationic photocurable bio-based polyurethane dispersion, and then the photoinitiator, the defoamer, the thickener and the wetting agent are added in sequence, dispersed for 10-30 minutes, and filtered to obtain the water-based photocurable bio-based coating.

[0063] The paint film of the water-based photocurable bio-based paint of the present invention has the advantages of high gloss, high transparency, excellent water resistance and chemical resistance, high crosslinking density, good flexibility, excellent adhesion to various substrates, etc., and can be applied to high-end wood coatings, automotive coatings, metal anti-corrosion coatings and other industrial protective coatings.

[0064] A fourth aspect of the present invention provides an application of a water-based bio-based photocurable coating in the fields of wood product preparation, automobile manufacturing or metal product corrosion protection. DETAILED DESCRIPTION

[0065] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0066] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0067] The bio-based materials used in the following examples are special epoxy soybean oil GreenSoft D, special epoxy soybean oil GreenSoft H, and epoxy linseed oil ELO produced by Xingbang Polymer Materials Co., Ltd. 9-5 TM .

[0068] The hydrophilic modifier is CHES, CAPS or CABS produced by Aladdin;

[0069] The acrylic acid monomer is acrylic acid AA or methacrylic acid MAA produced by Sanmu Company;

[0070] The diamine is ethylenediamine EDA, hexamethylenediamine HMDA, 2-methylpentamethylenediamine or isophoronediamine IPDA produced by BASF;

[0071] The sulfonic acid neutralizing agent is triethylamine TEA, N,N-dimethylethanolamine DMEA or N,N-dimethylcyclohexylamine DMCHA from Dow Chemical Company;

[0072] The macromolecular diol is polyether diol N220, polybutylene adipate diol PBA2000 or polycarbonate diol PCDL2000 with a molecular weight of 1000 to 2000 produced by Perstorp;

[0073] The small molecule diol chain extenders are 1,4-butanediol BDO, 2,4-diethyl-1,5-pentanediol PD-9, ethyl butyl propanediol BEPD, 1,6-hexanediol HDO, and neopentyl glycol NPG from Aladdin;

[0074] The hydrophilic chain extender is dimethylol propionic acid DMPA, dimethylol butyric acid DMBA from Aladdin or Ymer N120 from Perstorp;

[0075] The epoxy resins are tetraglycidyl diaminodimethylenebenzene MF-4101, 4,5-epoxytetrahydrophthalic acid diglycidyl ester MF-3286, and triglycidyl-p-aminophenol MF-3102 produced by Hubei Zhenzhengfeng New Materials Co., Ltd.

[0076] Basic performance tests include: cationic light-cured bio-based polyurethane dispersions are tested in accordance with GB / T11175-2002 "Test Methods for Synthetic Resin Emulsions", and the appearance, pH, solid content, and viscosity of the emulsion are tested. The average particle size of the dispersion is measured using a nanoparticle size analyzer (ZS Nano S). The double bond and epoxy concentrations are obtained by theoretical calculations, and the double bond and epoxy concentrations are the ratio of the amount of double bond or epoxy substance to the mass of the solid content of the emulsion or coating, in mol / 100g.

[0077] Example 1

[0078] A cationic light-cured bio-based polyurethane dispersion 1 is prepared by the following steps:

[0079] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer containing a vinyl group and an isocyanate group A1 for standby use;

[0080] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM , when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A1, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, add 50 parts of deionized water, disperse at high speed for 5 minutes, and obtain a macromolecular hydrophilic amine chain extender dispersion B1 for standby use;

[0081] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C1 and set aside;

[0082] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C1 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added, and after reacting for 50 minutes, 15.1 parts of ethyl butyl propanediol BEPD were added, and the reaction was continued for 50 minutes. The mixture was cooled to 40°C, 14.9 parts of MF-3286 were added, and the mixture was stirred for 10 minutes. 66 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes. 100.6 parts of macromolecular amine chain extender dispersion B1 were added, the mixture was heated to 55°C, and the mixture was dispersed and reacted at high speed for 15 minutes. 77 parts of deionized water were added, and the mixture was stirred for 15 minutes. The mixture was cooled to 40°C, and the material was filtered to obtain a cationic light-cured bio-based polyurethane dispersion 1.

[0083] Example 2

[0084] A cationic light-cured bio-based polyurethane dispersion 2 is prepared by the following steps:

[0085] S1. In parts by mass, 10.7 parts of hexamethylene diisocyanate HDI were heated to 55 ° C, and 8.4 parts of triethylene glycol divinyl ether DVE were added dropwise at a constant pressure within 10 minutes, and the reaction was continued for 0.8 hours to obtain a prepolymer containing a vinyl group and an isocyanate group A2, which was set aside;

[0086] S2. In parts by mass, 21.8 parts of epoxy soybean oil Green soft H were added to a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel. When heated to 75 ° C, 3.5 parts of cyclohexylaminoethanesulfonic acid CHES were added, and the reaction was continued for 1.0 hour. The temperature was raised to 145 ° C and 4.0 parts of methacrylic acid MAA were added dropwise at a constant pressure within 10 minutes. After the dripping, the mixture was stirred and kept warm for 20 minutes, cooled to 75 ° C, 19.1 parts of A1 were added, stirred and kept warm for 55 minutes, 5.7 parts of isophorone diamine were added, stirred and kept warm for 25 minutes, 1.7 parts of N, N-dimethylcyclohexylamine DMCHA were added, stirred for 5 minutes, 55 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes to obtain a macromolecular hydrophilic amine chain extender dispersion B2 for standby use;

[0087] S3. In parts by mass, 2.0 parts of Ymer N120, 2.7 parts of dimethylol propionic acid DMPA and 1.6 parts of triethylamine TEA were mixed to form a mixture C2 for later use;

[0088] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polycarbonate diol PCDL2000 and mixture C2 were added, by mass, and stirring was started. The mixture was heated to 75°C and stabilized for 15 minutes. 35.1 parts of isophorone diisocyanate IPDI were added. After reacting for 60 minutes, 15.1 parts of PD-9 were added. The reaction was continued for 60 minutes. The mixture was cooled to 45°C, 13.9 parts of MF-3102 were added, and the mixture was stirred for 5 minutes. 72 parts of deionized water were added, and the mixture was dispersed at high speed for 10 minutes. 110.8 parts of macromolecular amine chain extender dispersion B2 were added, the mixture was heated to 50°C, dispersed at high speed and reacted for 25 minutes. 85 parts of deionized water were added, and the mixture was stirred for 10 minutes. The mixture was cooled to 40°C, and the material was filtered to obtain cationic light-cured bio-based polyurethane dispersion 2.

[0089] Example 3

[0090] A cationic light-cured bio-based polyurethane dispersion 3 is prepared by the following steps:

[0091] S1. In parts by mass, 11 parts of toluene diisocyanate TDI were heated to 60 ° C, and 10.8 parts of cyclohexyl-1,4-dimethanol monovinyl ether were added dropwise at a constant pressure within 25 minutes, and the reaction was continued for 0.5 hours to obtain a prepolymer A3 containing a vinyl group and an isocyanate group, which was set aside;

[0092] S2. In parts by mass, 22.6 parts of epoxy soybean oil Green soft D were added to a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel. When heated to 80 ° C, 3.7 parts of cyclohexylaminopropanesulfonic acid CAPS were added, and the reaction was continued for 1.0 hour. The temperature was raised to 150 ° C and 3.4 parts of acrylic acid AA were added dropwise at a constant pressure within 5 minutes. After the dripping, the mixture was stirred and kept warm for 20 minutes, and the temperature was lowered to 70 ° C. 21.8 parts of A1 were added, stirred and kept warm for 50 minutes, 2.0 parts of ethylenediamine were added, stirred and kept warm for 20 minutes, 1.7 parts of N, N-dimethylcyclohexylamine DMCHA were added, stirred for 5 minutes, 52 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes to obtain a macromolecular hydrophilic amine chain extender dispersion B3 for standby use;

[0093] S3. In parts by mass, 2.5 parts of Ymer N120, 2.3 parts of dimethylol propionic acid DMPA and 1.3 parts of triethylamine TEA were mixed to form a mixture C3 and set aside;

[0094] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polyether diol N220 and mixture C3 were added, by mass, and stirring was started. The mixture was heated to 70°C and stabilized for 15 minutes. 27.5 parts of toluene diisocyanate TDI were added. After reacting for 60 minutes, 8.5 parts of 1,4-butanediol BDO were added. The reaction was continued for 45 minutes. The mixture was cooled to 40°C, 21.1 parts of MF-4101 were added, and the mixture was stirred for 5 minutes. 68 parts of deionized water were added, and the mixture was dispersed at high speed for 10 minutes. 107.2 parts of macromolecular amine chain extender dispersion B3 were added, the mixture was heated to 50°C, and the mixture was dispersed and reacted at high speed for 20 minutes. 80 parts of deionized water were added, and the mixture was stirred for 20 minutes. The mixture was cooled to 40°C, and the material was filtered to obtain cationic light-cured bio-based polyurethane dispersion 3.

[0095] Comparative Example 1

[0096] A cationic light-cured bio-based polyurethane dispersion 4, the difference between this comparative example and the example is that no epoxy resin is added, which is prepared by the following steps:

[0097] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer containing a vinyl group and an isocyanate group A4, which was set aside;

[0098] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM, when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A4, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, add 50 parts of deionized water, disperse at high speed for 5 minutes, and obtain macromolecular hydrophilic amine chain extender dispersion B4 for standby use;

[0099] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C4 and set aside;

[0100] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C4 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added. After reacting for 50 minutes, 15.1 parts of ethyl butyl propylene glycol BEPD were added. The reaction was continued for 50 minutes. The mixture was cooled to 40°C, 58 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes. 100.6 parts of macromolecular amine chain extender dispersion B4 were added. The mixture was heated to 55°C, dispersed at high speed and reacted for 15 minutes. 69 parts of deionized water were added, and the mixture was stirred for 15 minutes. The mixture was cooled to 40°C, and the material was filtered to obtain cationic light-cured bio-based polyurethane dispersion 4.

[0101] Comparative Example 2

[0102] A cationic light-cured bio-based polyurethane dispersion 5, the difference between this comparative example and the example is that the epoxy resin addition ratio is too high, which is prepared by the following steps:

[0103] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer containing a vinyl group and an isocyanate group A5, which was set aside;

[0104] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM, when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A5, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, add 50 parts of deionized water, disperse at high speed for 5 minutes, and obtain macromolecular hydrophilic amine chain extender dispersion B5 for standby use;

[0105] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C5 for later use;

[0106] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C5 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added. After reacting for 50 minutes, 15.1 parts of ethyl butyl propylene glycol BEPD were added. The reaction was continued for 50 minutes. The mixture was cooled to 40°C, 29.8 parts of MF-3286 were added, and the mixture was stirred for 10 minutes. 73 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes. 100.6 parts of macromolecular amine chain extender dispersion B5 were added, the mixture was heated to 55°C, and the mixture was dispersed and reacted at high speed for 15 minutes. 86 parts of deionized water were added, and the mixture was stirred for 15 minutes. The mixture was cooled to 40°C, and the material was filtered to obtain cationic light-cured bio-based polyurethane dispersion 5.

[0107] Comparative Example 3

[0108] A cationic light-curable bio-based polyurethane dispersion 6, the difference between this comparative example and the example is that the macromolecular amine chain extender is not pre-dispersed with water, and the dispersion viscosity is low before B6 is added, which is prepared by the following steps:

[0109] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer containing a vinyl group and an isocyanate group A6, which was set aside;

[0110] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM, when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A6, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, and obtain macromolecular hydrophilic amine chain extender B6 for standby use;

[0111] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C6 for later use;

[0112] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C1 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added, and after reacting for 50 minutes, 15.1 parts of ethyl butyl propylene glycol BEPD were added, and the reaction was continued for 50 minutes. The mixture was cooled to 40°C, 14.9 parts of MF-3286 were added, and stirred for 10 minutes. 193 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes. 50.6 parts of macromolecular amine chain extender B6 were added, and the mixture was heated to 55°C, dispersed and reacted at high speed for 15 minutes, and cooled to 40°C. The material was filtered to obtain cationic light-cured bio-based polyurethane dispersion 6.

[0113] Comparative Example 4

[0114] A cationic light-cured bio-based polyurethane dispersion 7, the difference between this comparative example and the example is that the polyurethane prepolymer is not dispersed with water before B7 is added, and it is prepared by the following steps:

[0115] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer containing a vinyl group and an isocyanate group A7, which was set aside;

[0116] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM, when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A7, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, add 50 parts of deionized water, disperse at high speed for 5 minutes, and obtain a macromolecular hydrophilic amine chain extender dispersion B7 for standby use;

[0117] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C7 for later use;

[0118] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C7 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added. After reacting for 50 minutes, 15.1 parts of ethyl butyl propanediol BEPD were added. The reaction was continued for 50 minutes. The mixture was cooled to 40°C, 14.9 parts of MF-3286 were added, and the mixture was stirred for 10 minutes. 100.6 parts of macromolecular amine chain extender dispersion B7 were added, and the mixture was dispersed at high speed for 5 minutes. 66 parts of deionized water were added, the mixture was heated to 55°C, and the mixture was dispersed and reacted at high speed for 15 minutes. 77 parts of deionized water were added, and the mixture was stirred for 15 minutes. The mixture was cooled to 40°C, and the material was filtered to obtain cationic light-cured bio-based polyurethane dispersion 7.

[0119] Comparative Example 5

[0120] A cationic light-curable bio-based polyurethane dispersion 8, the difference between this comparative example and the example is that neither the polyurethane prepolymer nor the macromolecular amine chain extender is pre-dispersed with water, and is prepared by the following steps:

[0121] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer containing a vinyl group and an isocyanate group A8, which was set aside;

[0122] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM, when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A8, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, and obtain macromolecular hydrophilic amine chain extender B8 for standby use;

[0123] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C8 and set aside;

[0124] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C8 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added. After reacting for 50 minutes, 15.1 parts of ethyl butyl propanediol BEPD were added. The reaction was continued for 50 minutes. The mixture was cooled to 40°C, 14.9 parts of MF-3286 were added, and stirred for 10 minutes. 50.6 parts of macromolecular amine chain extender B7 were added. The mixture was heated to 55°C and reacted for 15 minutes. 193 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes. The mixture was cooled to 40°C and filtered to obtain cationic light-cured bio-based polyurethane dispersion 8.

[0125] Comparative Example 6

[0126] A cationic light-cured bio-based polyurethane dispersion 9. The difference between this comparative example and the example is that the epoxy resin in Example 1 is replaced by epoxy resin E-51 (a difunctional epoxy resin belonging to bisphenol A type epoxy resin), and the other conditions are the same.

[0127] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer containing a vinyl group and an isocyanate group A9, which was set aside;

[0128] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM, when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A9, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, add 50 parts of deionized water, disperse at high speed for 5 minutes, and obtain a macromolecular hydrophilic amine chain extender dispersion B9 for standby use;

[0129] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C9 for later use;

[0130] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C9 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added, and after reacting for 50 minutes, 15.1 parts of ethyl butyl propylene glycol BEPD were added, and the reaction was continued for 50 minutes. The mixture was cooled to 40°C, 14.9 parts of E-51 were added, and the mixture was stirred for 10 minutes. 66 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes. 100.6 parts of macromolecular amine chain extender dispersion B9 were added, the mixture was heated to 55°C, and the mixture was dispersed and reacted at high speed for 15 minutes. 77 parts of deionized water were added, and the mixture was stirred for 15 minutes. The mixture was cooled to 40°C, and the material was filtered to obtain a cationic light-cured bio-based polyurethane dispersion 9.

[0131] Comparative Example 7

[0132] A cationic light-cured bio-based polyurethane dispersion 10, in which too much water is added during the pre-dispersion of the urethane prepolymer in this embodiment, specifically:

[0133] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer A10 containing a vinyl group and an isocyanate group, which was set aside;

[0134] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM, when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A10, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, add 50 parts of deionized water, disperse at high speed for 5 minutes, and obtain a macromolecular hydrophilic amine chain extender dispersion B10 for standby use;

[0135] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C10 for later use;

[0136] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C10 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added, and after reacting for 50 minutes, 15.1 parts of ethyl butyl propylene glycol BEPD were added, and the reaction was continued for 50 minutes. The mixture was cooled to 40°C, 14.9 parts of MF-3286 were added, and stirred for 10 minutes. 143 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes. 100.6 parts of macromolecular amine chain extender dispersion B10 were added, and the mixture was heated to 55°C, dispersed and reacted at high speed for 15 minutes, and cooled to 40°C. The material was filtered to obtain a cationic light-cured bio-based polyurethane dispersion 10.

[0137] In this comparative example, too much water is added during the pre-dispersion of the polyurethane prepolymer. When the viscosity is too low, it is not conducive to the fusion of the polyurethane prepolymer and the macromolecular amine chain extender. If too little water is added, it is not conducive to the polyurethane prepolymer wrapping the epoxy resin to form a core-shell structure.

[0138] Comparative Example 8

[0139] A cationic light-curable bio-based polyurethane dispersion 11. The difference between this comparative example and the example is that the macromolecular chain extender is not pre-dispersed with water, and the other conditions are the same:

[0140] S1. In parts by mass, 14.1 parts of isophorone diisocyanate IPDI were heated to 50 ° C, and 7.4 parts of 4-hydroxybutyl vinyl ether HBVE were added dropwise at a constant pressure within 15 minutes, and the reaction was continued for 1 hour to obtain a prepolymer containing a vinyl group and an isocyanate group A11, which was set aside;

[0141] S2. Add 16.6 parts of epoxy linseed oil ELO in a four-necked flask equipped with a thermometer, condenser, stirring paddle and constant pressure dropping funnel. 9-5 TM, when heated to 70°C, add 3.9 parts of cyclohexylaminobutanesulfonic acid CABS, react for 1.5 hours, heat to 140°C, and drip 3.3 parts of acrylic acid AA at constant pressure within 10 minutes, stir and keep warm for 25 minutes after dripping, cool to 70°C, add 21.5 parts of A11, stir and keep warm for 60 minutes, add 3.9 parts of 2-methylpentanediamine, stir and keep warm for 30 minutes, add 1.4 parts of triethylamine TEA, stir for 3 minutes, and obtain macromolecular hydrophilic amine chain extender B11 for standby use;

[0142] S3. In parts by mass, 2.5 parts of Ymer N120, 2.5 parts of dimethylolbutyrate DMBA and 1.3 parts of triethylamine TEA were mixed to form a mixture C11 for later use;

[0143] S4. In a four-necked flask equipped with a thermometer, a condenser, a stirring paddle and a constant pressure dropping funnel, 15 parts of polybutylene adipate diol PBA2000 and mixture C11 were added, by mass, and stirring was started. The mixture was heated to 80°C and stabilized for 15 minutes. 26.6 parts of diisocyanate HDI were added, and after reacting for 50 minutes, 15.1 parts of ethyl butyl propylene glycol BEPD were added, and the reaction was continued for 50 minutes. The mixture was cooled to 40°C, 14.9 parts of MF-3286 were added, and stirred for 10 minutes. 66 parts of deionized water were added, and the mixture was dispersed at high speed for 5 minutes. 50.6 parts of macromolecular amine chain extender B11 were added, and the mixture was heated to 55°C, dispersed and reacted at high speed for 15 minutes. The mixture was cooled to 40°C, 127 parts of deionized water were added, and stirred for 15 minutes. The material was filtered to obtain cationic light-cured bio-based polyurethane dispersion 11.

[0144] Test Example 1

[0145] Test Example A water-based photocurable bio-based coating was prepared, and the cationic photocurable bio-based polyurethane dispersion was prepared in the examples and comparative examples. The specific steps were:

[0146] The water-based photocurable bio-based coating is composed of the following components in parts by weight:

[0147]

[0148] The preparation method of the water-based photocurable bio-based coating is as follows: a cationic photocurable bio-based polyurethane dispersion is added into a stirring tank at a rotation speed of 700 rpm, water, dipropylene glycol butyl ether and dipropylene glycol methyl ether are premixed and added into the stirring tank, Darocur 1173, Omnirad 250, TEGO-800, RM-8W and TEGO-245 are added in sequence, dispersed for 20 minutes, and the material is filtered to obtain a water-based photocurable bio-based coating.

[0149] The paint film made of water-based photocurable bio-based coating was dried at 50°C for 2 hours, and the photocuring machine was turned on with a mercury lamp and the UVA energy was adjusted to 600mJ / cm 2 The properties are shown in Table 1.

[0150] The test standards are as follows:

[0151] Coating appearance: visual inspection;

[0152] Pencil hardness: GB / T 6739-2006;

[0153] Coating gloss / (60°,%): GB / T 9754-2007;

[0154] Water resistance (25°C, 24h): GB / T 4893.1-2020;

[0155] Dry heat resistance (70±2℃, 15h): GB / T 4893.3-2020;

[0156] Ethanol resistance (50%, 1h): GB / T 4893.1-2020;

[0157] Adhesion: GB / T 9286-2021;

[0158] Table 1 Performance parameters of cationic photocurable bio-based polyurethane dispersions and waterborne photocurable bio-based coatings

[0159]

[0160] As can be seen from the above table, compared with Example 1, Comparative Example 1 has poor cationic light curing effect, poor film resistance and adhesion due to the fact that no epoxy resin is added to its cationic light-cured bio-based polyurethane dispersion; Compared with Example 1, Comparative Example 2 has poor wet film appearance and storage stability due to the excessively high proportion of epoxy resin added to its cationic light-cured bio-based polyurethane dispersion. In addition, due to the high functionality of the epoxy resin, the paint film is brittle and the adhesion is poor. Compared with Example 1, Comparative Example 3 has a low dispersion viscosity before B6 is added, and B6 cannot fully react with the isocyanate group, which ultimately causes problems such as poor wet film transparency, low gloss, poor resistance, and poor adhesion to some substrates. Compared with Example 1, Comparative Example 4 has no water dispersion before B7 is added, so the epoxy and isocyanate groups in the prepolymer react with the amine groups in B7, and some epoxy groups are consumed, which ultimately causes problems such as poor film resistance and poor adhesion to some substrates. Compared with Example 1, in Comparative Example 5, since the polyurethane prepolymer was not dispersed with water before B8 was added, and the macromolecular chain extender was dispersed with water after the reaction with the polyurethane prepolymer, the molecular weight before dispersion was too large and the viscosity was too high, which was not conducive to dispersion, so the storage stability deteriorated. In addition, part of the epoxy group was consumed, which eventually caused the problems of poor film resistance and poor adhesion of some substrates. Compared with Example 1, in Comparative Example 6, since the epoxy group reaction activity of the difunctional bisphenol A epoxy resin E-51 was lower than that of the trifunctional glycidyl ester epoxy resin MF-3286, the final paint film had poor resistance and low hardness. Compared with Example 1, in Comparative Example 7, too much water was added during the pre-dispersion of the polyurethane prepolymer, and when the viscosity was too low, it was not conducive to the fusion of the polyurethane prepolymer and the macromolecular amine chain extender, resulting in poor dispersion stability, poor transparency of the paint film, poor resistance, and low hardness. Compared with Example 1, in Comparative Example 8, since the macromolecular amine chain extender was not pre-dispersed, part of the macromolecular amine chain extender reacted with the epoxy resin, resulting in poor paint film resistance and poor adhesion. From Examples 1, 2, and 3, it can be seen that the present invention discloses a method for preparing a cationic light-cured bio-based polyurethane dispersion, and the paint film made of the prepared cationic light-cured bio-based coating has the advantages of good flexibility, good water resistance and chemical resistance, and excellent adhesion to a variety of substrates, and can be applied to high-end wood coatings, automotive coatings, metal anticorrosive coatings, and other industrial protective coatings.

[0161] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for preparing a cationic photocurable bio-based polyurethane dispersion, characterized in that: The preparation method comprises the following steps: S1. The isocyanate monomer and the hydroxy vinyl ether are mixed and reacted to obtain a prepolymer A1 containing a vinyl group and an isocyanate group; S2. After the bio-based material and the hydrophilic modifier are mixed and reacted, acrylic monomer, diamine and neutralizing agent are added, mixed and dispersed in water to obtain a macromolecular hydrophilic amine chain extender dispersion B1; S3. The hydrophilic chain extender and the neutralizing agent are mixed to form a mixture C1; S4. The macromolecular diol, the mixture C1, the isocyanate monomer, the small molecule diol chain extender and the epoxy resin are mixed and reacted, dispersed with water, and then mixed with the macromolecular hydrophilic amine chain extender dispersion B1 and dispersed with water; The raw materials for preparing the bio-based material include vegetable oil containing more than three epoxy groups; The hydrophilic modifier includes a monomer containing a secondary amino group and a sulfonic acid group; The epoxy resin includes an epoxy resin containing three or more epoxy groups.

2. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: S1. In parts by mass, 10 to 15 parts of diisocyanate are heated to 40 to 60°C and then 6 to 12 parts of hydroxy vinyl ether are added dropwise, and the reaction is continued to obtain a prepolymer A1 containing a vinyl group and an isocyanate group; S2. In terms of mass fractions, 15 to 25 parts of bio-based materials are heated to 70 to 90°C, 3 to 5 parts of hydrophilic modifiers are added, reacted, heated to 130 to 150°C, 3 to 4.5 parts of acrylic acid monomers are added dropwise, stirred and kept warm after the addition is complete, cooled to 70 to 80°C, 17 to 25 parts of A1 are added, stirred and kept warm, 2 to 6 parts of diamine are added, stirred and kept warm, 1.0 to 2.0 parts of neutralizer are added, stirred, 50 to 55 parts of deionized water are added, and dispersed to obtain a macromolecular hydrophilic amine chain extender dispersion B1; S3. Mix 4 to 6 parts by mass of a hydrophilic chain extender and 1 to 2 parts of a neutralizing agent to form a mixture C1; S4. In terms of mass fractions, 10 to 20 parts of macromolecular diol and mixture C1 are mixed and heated to 70 to 80°C, 25 to 36 parts of diisocyanate monomers are added after stabilization, 8 to 16 parts of small molecule diol chain extenders are added after the reaction, the reaction is continued, the temperature is lowered to 40 to 50°C, 10 to 25 parts of epoxy resin are added, stirred, 65 to 75 parts of deionized water are added, dispersed, 100 to 115 parts of macromolecular hydrophilic amine chain extender dispersion B1 are added, 75 to 85 parts of deionized water are added, the temperature is raised to 50 to 60°C, dispersed and reacted, and the cationic light-cured bio-based polyurethane dispersion is obtained.

3. The preparation method according to claim 1, characterized in that: The isocyanate monomer includes at least one of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

4. The preparation method according to claim 1, characterized in that: The hydroxy vinyl ether includes at least one of 4-hydroxybutyl vinyl ether, triethylene glycol divinyl ether and cyclohexyl-1,4-dimethanol monovinyl ether.

5. The preparation method according to claim 1, characterized in that: The diamine includes at least one of ethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine and isophoronediamine.

6. A cationic photocurable bio-based polyurethane dispersion, characterized in that: The cationic light-curable bio-based polyurethane dispersion is prepared by the preparation method according to any one of claims 1 to 5, and the bio-based content of the dispersion is ≥ 12%.

7. A water-based bio-based photocurable coating, characterized in that: The preparation raw materials include the cationic light-curable bio-based polyurethane dispersion described in claim 6.

8. The water-based bio-based photocurable coating according to claim 7, characterized in that: By weight, the preparation comprises the following raw materials in parts by weight:

9. The water-based bio-based photocurable coating according to claim 8, characterized in that: The preparation method of the water-based bio-based photocurable coating comprises: premixing water and a film-forming aid into a cationic photocurable bio-based polyurethane dispersion, sequentially adding a photoinitiator, a defoamer, a thickener and a wetting agent, dispersing for 10-30 minutes, and filtering to obtain the water-based photocurable bio-based coating.

10. Use of the waterborne bio-based photocurable coating according to any one of claims 7 to 8 in the fields of wood product preparation, automobile manufacturing or metal product corrosion protection.

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