CN109749071B - Silicon-containing waterborne UV (ultraviolet) bio-based unsaturated polyester and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of coatings, and discloses a silicon-containing water-based UV bio-based unsaturated polyester and a preparation method thereof. The method comprises the following steps: mixing bio-based diol and carboxyl group-containing diol to form a clear liquid, adding silane coupling agent, catalyst and polymerization inhibitor to it, a modification reaction occurs, and adding to it after the modification reaction is completed The bio-based dibasic acid, catalyst and polymerization inhibitor undergo a photocuring reaction. After the photocuring reaction is over, the product is cooled to room temperature, then neutralized by adding a neutralizer, and then mixed with a photoinitiator to obtain a silicon-containing water-based solution. UV bio-based unsaturated polyester. The present invention introduces Si-O bond through modification, improves weather resistance, thermal degradation temperature and hardness, and the obtained product has no obvious change in 3 months and has good stability, indicating that the present invention improves the water-based UV unsaturated polyester comprehensive performance.

Description

A kind of water-based UV bio-based unsaturated polyester containing silicon and preparation method thereof

technical field

The invention belongs to the field of coatings, in particular to a silicon-containing water-based UV bio-based unsaturated polyester and a preparation method thereof.

Background technique

Water-based UV coatings take into account the advantages of both water-based and UV-curable coatings, and have excellent construction operability and environmental protection performance. It is a new type of green material that has been studied more.

At present, the monomers for synthesizing water-based paint oligomers mostly come from a kind of fossil energy—petroleum. However, such petroleum-based polymer materials have a long degradation cycle in the natural environment, and some are difficult to degrade. Over time, they will cause pollution to soil and water bodies. On the other hand, fossil energy such as petroleum is not renewable. Since the Industrial Revolution, the global The utilization rate of fossil energy such as oil is increasing year by year. According to the current rate of human consumption of fossil energy, some researchers predict that the global fossil energy will be exhausted by 2050. Green, recyclable bio-based chemical materials are favored by industry and researchers. Bio-based materials refer to biomass synthetic materials obtained through biosynthesis, bioprocessing, and biorefinery using renewable resources such as crops, wastes, trees, other plants and their residues and inclusions as raw materials. The large-scale development and application of base materials can reduce the chemical material industry's dependence on fossil resources, which is conducive to environmental improvement and coordinated economic development.

Itaconic acid has been rated as one of the 12 most potential bio-based chemical materials by the US Department of Energy. It has two COOH and one α, β unsaturated double bond, and its chemical properties are very active. In addition to bulk polymerization, it can also carry out copolymerization with other olefin monomers, and can carry out various esterification reactions, addition reactions and polymerization reactions, thereby preparing various new polymer materials. At present, the production of itaconic acid mainly relies on the production of low-cost agricultural and sideline products such as straw, sugarcane, sugar beet, starch, and distiller's grains under the action of Candida, Aspergillus itaconate, Aspergillus terreus and other strains. Its raw material sources are extensive and renewable, and the obtained bio-based products have less environmental pollution and have huge application potential and value.

The preparation method of unsaturated polyester is relatively simple, but it has disadvantages such as low hardness, poor weather resistance, and poor hydrophobicity, which limit its market space. In the prior art, there are relatively few modifications to unsaturated polyesters, mainly focusing on the following points: (1) introducing a long-chain dibasic acid or dibasic alcohol, although this method can improve flexibility, the chain growth makes The cross-linking curing density decreases and the hardness decreases; (2) Modification is carried out by using the good photoelectric effect of inorganic nanoparticles. Although this method can improve the hardness and make the prepared paint film have certain photoelectric properties, the inorganic nanoparticles have easy The characteristics of agglomeration are that it is difficult to disperse uniformly in the resin. Even if the dispersion is uniform, the storage time is also a problem; (3) Some long-chain silicone resins, fluororesins or fluorosilicones are used for modification by copolymerization, etc. Although this method is Elements such as Si and F are introduced, but due to the long chain of silicon and fluorine, it will inevitably affect the density of photocuring, thereby affecting the adhesion, and the chain length of such monomers is different, and the performance is not uniform. The molecular chain structure cannot be well controlled.

Therefore, it is necessary to develop a bio-based water-based UV resin with good comprehensive properties.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing a silicon-containing water-based UV bio-based unsaturated polyester. The present invention adopts a monomer containing an active functional group, firstly synthesizes a modified body of a small molecule with a fixed chain segment and an active group, and then through block copolymerization, there is no problem of inorganic nanomaterials It can also control the molecular chain structure of the resin well and give full play to the performance of the introduced Si.

Another object of the present invention is to provide a silicon-containing water-based UV bio-based unsaturated polyester prepared by the above method

Another object of the present invention is to provide the application of the above-mentioned silicon-containing water-based UV bio-based unsaturated polyester in varnish on paper, leather surface coating, glass and ceramic tile coating sub-base.

The object of the present invention is realized through the following scheme:

A preparation method of a silicon-containing water-based UV bio-based unsaturated polyester, comprising the following steps:

(1) mixing bio-based diol and carboxyl-containing diol to form clear liquid;

(2) adding a silane coupling agent, a catalyst and a polymerization inhibitor to the clear liquid in the step (1), and a modification reaction occurs;

(3) adding a bio-based dibasic acid, a catalyst, and a polymerization inhibitor to the product after the modification reaction in step (2), and a photocuring reaction occurs;

(4) After the product after the photocuring reaction in step (3) is cooled to room temperature, a neutralizing agent is added for neutralization, and then mixed with a photoinitiator to obtain a silicon-containing water-based UV bio-based unsaturated polyester.

The bio-based diol described in step (1) is at least one of 1,4-butanediol, 1,3-propanediol, and 2,3-butanediol, preferably 1,4-butanediol; The carboxyl-containing diol is at least one of 2,2 dimethylol propionic acid and dimethylol butyric acid, preferably 2,2 dimethylol propionic acid;

The dosage of the bio-based diol and the carboxyl-containing diol described in step (1) is such that the carboxyl-containing diol accounts for 5-30% of the total molar amount of the bio-based diol and the carboxyl-containing diol;

The silane coupling agent described in step (2) is a silane coupling agent containing an epoxy functional group, preferably at least one of silane coupling agent KH560, silane coupling agent SCA-403, and silane coupling agent A-186. The consumption of described silane coupling agent satisfies that the mol ratio of silane coupling agent and carboxyl-containing diol is 1:1;

The catalyst described in step (2) is at least one of concentrated sulfuric acid (96wt%～98wt%), p-toluenesulfonic acid, N,N dimethylbenzylamine and triphenylphosphine; preferably N,N two At least one of methylbenzylamine and triphenylphosphine; the dosage of the catalyst is 0.5% to 1.0% of the total mass of the carboxyl-containing diol and the silane coupling agent.

The polymerization inhibitor described in the step (2) is at least one of hydroquinone (1,4-dihydroxybenzene); the consumption of the polymerization inhibitor is the coupling of carboxyl-containing diol and silane 0.5% to 1.0% of the total mass of the agent.

The modification reaction described in step (2) refers to the reaction at 85-95° C. for 1.5-2.5 h until the acid value is reduced to 25-35 mg(KOH)/g.

The bio-based dibasic acid described in the step (3) is itaconic acid (methylidene succinic acid, methylene succinic acid), and the consumption of the bio-based dibasic acid satisfies the molar weight of the bio-based dibasic acid It is 1.1-1.5 times of the total molar amount of bio-based diol and carboxyl-containing diol in step (1);

The catalyst described in step (3) is at least one of concentrated sulfuric acid (96wt%～98wt%), p-toluenesulfonic acid, N,N dimethylbenzylamine (BDMA), triphenylphosphine; preferably concentrated At least one of sulfuric acid and p-toluenesulfonic acid (PTSA); the dosage of the catalyst is 0.5% to 1.0% of the total mass of itaconic acid, bio-based diol and carboxyl-containing diol.

At least one of the polymerization inhibitor described in the step (3), p-hydroxyanisole, and hydroquinone (1,4-dihydroxybenzene); the consumption of the polymerization inhibitor is itaconic acid, biological 0.5% to 1.0% of the total mass of the base diol and the carboxyl group-containing diol.

The photocuring reaction described in the step (3) refers to the reaction at 135 °C for 2 to 3 hours under the protection of an inert gas until the acid value reaches 200 to 240 mg(KOH)/g, then the temperature is kept at 135 °C, and the vacuum reaction is continued for 1 ~1.5h, the pressure is 0.085 ~ 0.095MPa.

The neutralizing agent described in the step (4) is at least one of triethylamine, triethanolamine, N,N dimethylethanolamine, ammonia water; the consumption of the neutralizing agent satisfies the neutralization of the obtained target product degree of 30% to 45%;

The photoinitiators described in step (4) are 1173 (2-hydroxy-2-methyl-1-phenyl-1-acetone), 2959 (2-hydroxy-4'-(2-hydroxyethoxy) -2-methylpropiophenone), at least one of polyethylene glycol (β-4[p-(2-dimethylamine-2-benzyl)butyrylphenyl]oxazine) propionate; The dosage of the photoinitiator meets the mass fraction of 3-6% of the photoinitiator in the obtained silicon-containing water-based UV bio-based unsaturated polyester.

In the preparation method of the present invention, in order to ensure that the reaction is mild and controllable, and the viscosity of the prepared resin is relatively low, the addition of the reaction raw materials in the steps (2) and (3) is preferably by first mixing the raw materials to be added uniformly, and then adding them in batches; As in step (2), when adding the silane coupling agent, the catalyst and the polymerization inhibitor, it is preferable to mix the three evenly, and then add them in batches.

A silicon-containing water-based UV bio-based unsaturated polyester prepared by the above method.

The application of the above-mentioned silicon-containing water-based UV bio-based unsaturated polyester in paper varnish, leather surface coating, glass and ceramic tile coating sub-base.

The mechanism of the present invention is:

Take the bio-based diol as 1,4-butanediol, the carboxyl-containing diol as 2,2-dimethylolpropionic acid, the bio-based dibasic acid as itaconic acid, and the silane coupling agent as KH560 as an example , the reaction mechanism is as follows:

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The present invention abandons traditional petroleum-based monomers, and the main reactants are itaconic acid and 1,4-butanediol fermented by microorganisms. The cost of the two materials is relatively low, which can alleviate the pressure of fossil energy consumption and is sustainable. development is important;

(2) The present invention aims at the shortcomings of unsaturated polyester with poor performance such as high temperature resistance, hydrophobicity and hardness. Through modification, Si-O bonds are introduced to improve weather resistance, thermal degradation temperature and hardness, and the obtained product is in There is no obvious change in 3 months, and the stability is good, indicating that the present invention improves the comprehensive performance of the water-based UV unsaturated polyester.

(3) In addition, the present invention adopts the method of adding monomers in batches in multiple steps, so that the appearance of the prepared polyester is light yellow and clear, and the viscosity is lower than that of the traditional one-step addition method.

Detailed ways

The present invention will be described in further detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

The reagents used in the examples can be routinely purchased from the market unless otherwise specified.

Example 1

(1) Weigh 8.56g of 1,4 butanediol and 0.67g of 2,2 dimethylolpropionic acid, add them to a four-necked flask equipped with a circulating condensing device, heat up to 60°C, and stir evenly until 2,2 Dimethylolpropionic acid was dissolved, and the flask solution was clear;

(2) be warmed up to 90 ℃, in the beaker, take by weighing the same KH560 with 2,2 dimethylolpropionic acid molar amount, the quality is 1.18g, simultaneously take N,N dimethylbenzylamine 0.02g and p-hydroxyl 0.02g of anisole, stirred and mixed with KH560 evenly, then KH560 mixed with catalyst and polymerization inhibitor was slowly added into the four-necked flask in four batches. Add the next batch, after all the dropwise additions are completed, keep the reaction for 1.5h until the acid value drops to 30mg(KOH)/g;

(3) Warm up to 135°C, pass nitrogen, weigh 16.01g of itaconic acid, 0.245g of p-toluenesulfonic acid, and 0.245g of p-hydroxyanisole, divide the above 3 into 3 parts on average, and add one part of each. In the reactor, stir evenly. After all the itaconic acid is dissolved and the flask solution is clear, the next batch of itaconic acid is added. After all the itaconic acid is added, the reaction is kept for 2.5 hours until the acid value is 220 mg(KOH)/g. Vacuuming, the pressure is 0.090MPa, the reaction is continued for 1 h under vacuum conditions, then cooled to 60 °C, N,N dimethylethanolamine is added, the degree of neutralization is 40%, and the photoinitiator 1173 is added to mix to obtain a silicon-containing aqueous solution. UV bio-based unsaturated polyester, wherein the mass fraction of photoinitiator 1173 is 3%.

The appearance, viscosity and stability of the obtained polyester were measured. In addition, the synthesized unsaturated polyester was coated on the polished tinplate patch using a paint film applicator, and cured by a 300nm UV curing machine. For 40s, the adhesion, hardness, water contact angle and thermal degradation performance were measured. The results are shown in Table 1 below:

Table 1 Performance test results of the silicon-containing water-based UV bio-based unsaturated polyester prepared in Example 1

Example 2

(1) Weigh 8.11g of 1,4 butanediol and 1.34g of 2,2 dimethylolpropionic acid into a four-necked flask equipped with a circulating condensing device, heat up to 60°C, and stir evenly until 2,22 The hydroxymethylpropionic acid was dissolved, and the flask solution was clear;

(2) be warmed up to 90 ℃, in the beaker, take by weighing the same KH560 with 2,2 dimethylolpropionic acid molar weight, the quality is 2.36g, simultaneously take N,N dimethylbenzylamine 0.03g and p-hydroxyl 0.03g of anisole, stir and mix with KH560, and then slowly add KH560 mixed with catalyst and polymerization inhibitor into the four-necked flask in four batches. One batch, after all the dropwise additions are completed, the reaction is incubated for 1.5h until the acid value drops to 30mg(KOH)/g;

(3) Warm up to 135°C, pass nitrogen, weigh 16.39g of itaconic acid, 0.24g of p-toluenesulfonic acid, and 0.24g of hydroquinone, divide the above 3 into 3 parts on average, and add one part to the reaction In the container, stir evenly. After all the itaconic acid is dissolved and the solution in the flask is clear, add the next batch of itaconic acid. After all the itaconic acid is added, keep the reaction for 2.5 hours until the acid value is 220 mg(KOH)/g, and then pump Vacuum, the pressure is 0.090MPa, and the reaction is continued for 1 h under vacuum conditions, and then cooled to 60 ° C. Triethanolamine is added, the degree of neutralization is 40%, and the photoinitiator 1173 is added and mixed to obtain a silicon-containing water-based UV bio-based unsaturated polymer. ester, wherein the mass fraction of photoinitiator 1173 is 3%.

The appearance, viscosity and stability of the obtained polyester were measured. In addition, the synthesized unsaturated polyester was coated on the polished tinplate patch using a paint film applicator, and cured by a 300nm UV curing machine. 40s, the adhesion, hardness, water contact angle and thermal degradation properties were measured. The performance results are shown in Table 2 below:

Table 2 Performance test results of the silicon-containing water-based UV bio-based unsaturated polyester prepared in Example 2

Example 3:

(1) Weigh 7.21g of 1,4 butanediol and 2.68g of 2,2 dimethylolpropionic acid, add them to a four-necked flask equipped with a circulating condensing device, heat up to 60°C, and stir evenly until 2,2 Dimethylolpropionic acid was dissolved, and the flask solution was clear;

(2) be warmed up to 90 ℃, in the beaker, take by weighing the same KH560 with 2,2 dimethylolpropionic acid molar weight, the quality is 4.72g, simultaneously take N,N dimethylbenzylamine 0.07g and p-hydroxyl 0.07g of anisole, stir and mix with KH560, then slowly add KH560 mixed with catalyst and polymerization inhibitor into the four-necked flask in four batches. One batch, after all the dropwise additions are completed, the reaction is incubated for 1.5h until the acid value drops to 30mg(KOH)/g;

(3) Warm up to 135°C, pass nitrogen, weigh 17.17g of itaconic acid, 0.27g of p-toluenesulfonic acid and 0.27g of p-hydroxyanisole, divide the above 3 into 3 parts on average, take one part of each and add In the reactor, stir evenly. After all the itaconic acid is dissolved and the flask solution is clear, the next batch of itaconic acid is added. After all the itaconic acid is added, the reaction is kept for 2.5 hours until the acid value is 220 mg(KOH)/g. Vacuuming, the pressure is 0.090MPa, the reaction is continued for 1 h under vacuum conditions, then cooled to 60 ° C, N,N dimethylethanolamine is added to make the degree of neutralization 40%, and photoinitiator 1173 is added to mix to obtain silicon-containing The water-based UV bio-based unsaturated polyester, wherein the mass fraction of photoinitiator 1173 is 3%.

The appearance, viscosity and stability of the obtained polyester were measured. In addition, the synthesized unsaturated polyester was coated on the polished tinplate patch using a paint film applicator, and cured by a 300nm UV curing machine. After 40s, the adhesion, hardness, water contact angle and thermal degradation properties were measured. The performance results are shown in Table 3 below:

Table 3 Performance test results of the silicon-containing water-based UV bio-based unsaturated polyester prepared in Example 3

Example 4:

(1) Weigh 6.3g of 1,4 butanediol and 4.02g of 2,2 dimethylolpropionic acid, add them to a four-necked flask equipped with a circulating condensing device, heat up to 60°C, and stir evenly until 2,2 Dimethylolpropionic acid was dissolved, and the flask solution was clear;

(2) be warming up to 90 ℃, in the beaker, take by weighing the same KH560 with 2,2 dimethylolpropionic acid molar weight, the quality is 7.08g, meanwhile, take by weighing N,N dimethylbenzylamine 0.11g and pair 0.11g of hydroxyanisole, stir and mix with KH560 evenly, then slowly add KH560 mixed with catalyst and polymerization inhibitor into the four-necked flask in four batches, about 10 minutes per batch, and then add the next batch at 15 minutes interval. batch, after all the dropwise additions are completed, the reaction is incubated for about 1.5h until the acid value drops to 30mg(KOH)/g;

(3) Warm up to 135°C, pass nitrogen, weigh 17.95g of itaconic acid, 0.28g of p-toluenesulfonic acid, and 0.28g of p-hydroxyanisole, divide the above 3 into 3 parts on average, and add one part of each. In the reactor, stir evenly. After all the itaconic acid is dissolved and the flask solution is clear, the next batch of itaconic acid is added. After all the itaconic acid is added, the reaction is kept for 2.5 hours until the acid value is 220 mg(KOH)/g. Vacuuming, the pressure is 0.090MPa, the reaction is continued for 1 h under vacuum conditions, then cooled to 60 ° C, triethylamine is added, the degree of neutralization is 40%, and photoinitiator 1173 is added to mix to obtain a silicon-containing water-based UV bio-based Unsaturated polyester, wherein the mass fraction of photoinitiator 1173 is 3%.

The appearance, viscosity and stability of the obtained polyester were measured. In addition, the synthesized unsaturated polyester was coated on the polished tinplate patch using a paint film applicator, and cured by a 300nm UV curing machine. After 40s, the adhesion, hardness, water contact angle and thermal degradation properties were measured. The performance results are shown in Table 4 below:

Table 4 Performance test results of silicon-containing water-based UV bio-based unsaturated polyester prepared in Example 4

Comparative Example 1 (silicon-free, no carboxyl-containing diol modification):

(1) Weigh 10.32g of 1,4 butanediol and add it to the four-necked flask equipped with the circulating condensing device, be warming up to 135°C, and pass nitrogen;

(2) Weighing 17.95g of itaconic acid, 0.28g of p-toluenesulfonic acid, and 0.28g of p-hydroxyanisole, adding the above three into a four-necked flask equipped with a circulating condensing device at one time, and keeping the reaction for 2.5h, then Vacuuming, the pressure is 0.090MPa, the reaction is kept under vacuum conditions for 1 h, then cooled to 60 ° C, triethylamine is added, the degree of neutralization is 40%, and photoinitiator 1173 is added to mix to obtain water-based UV bio-based unsaturated polyester , wherein the mass fraction of photoinitiator 1173 is 3%.

The appearance, viscosity and stability of the obtained polyester were measured. In addition, the synthesized unsaturated polyester was coated on the polished tinplate patch using a paint film applicator, and cured by a 300nm UV curing machine. After 40s, the adhesion, hardness, water contact angle and thermal degradation properties were measured. The performance results are shown in Table 5 below:

Table 5 Performance test results of the water-based UV bio-based unsaturated polyester prepared in Comparative Example 1

Comparative Example 2 (silicon-free, with carboxyl-containing diol):

(1) take by weighing 6.30g 1,4 butanediol and 4.02g 2,2 dimethylolpropionic acid, join in the four-necked flask equipped with circulating condensing device, be warming up to 135 ℃, pass nitrogen;

Weigh 17.95 g of itaconic acid, 0.28 g of p-toluenesulfonic acid, and 0.28 g of p-hydroxyanisole, and add the above three to a four-necked flask equipped with a circulating condensation device at one time, keep the reaction for 2.5 hours, and then vacuumize, The pressure is 0.090MPa, the reaction is kept under vacuum for 1h, then cooled to 60°C, triethylamine is added, the degree of neutralization is 40%, and photoinitiator 1173 is added to mix to obtain water-based UV bio-based unsaturated polyester, in which light The mass fraction of initiator 1173 was 3%.

The appearance, viscosity and stability of the obtained polyester were measured. In addition, the synthesized unsaturated polyester was coated on the polished tinplate patch using a paint film applicator, and cured by a 300nm UV curing machine. After 40s, the adhesion, hardness, water contact angle and thermal degradation properties were measured. The performance results are shown in Table 6 below:

Table 6 Performance test results of the water-based UV bio-based unsaturated polyester prepared in Comparative Example 2

As can be seen from Tables 1 to 6, the present invention uses a silane coupling agent to modify the carboxyl group-containing diol, and introduces Si-O bonds into the unsaturated polyester, thereby improving the weather resistance and thermal degradation temperature. and hardness, while reducing the viscosity, and the obtained product has no obvious change in 3 months, and has good stability, indicating that the present invention improves the comprehensive performance of the water-based UV unsaturated polyester.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (10)

1. A preparation method of silicon-containing waterborne UV bio-based unsaturated polyester is characterized by comprising the following steps:

(1) mixing bio-based diol and carboxyl-containing diol to form a clear liquid;

(2) adding a silane coupling agent, a catalyst and a polymerization inhibitor into the clear liquid obtained in the step (1) to perform modification reaction;

(3) adding bio-based dibasic acid, a catalyst and a polymerization inhibitor into the product obtained after the modification reaction in the step (2) to perform a photocuring reaction;

(4) cooling the product obtained after the photocuring reaction in the step (3) to room temperature, adding a neutralizer for neutralization, and then mixing with a photoinitiator to obtain silicon-containing waterborne UV (ultraviolet) bio-based unsaturated polyester;

the bio-based diol in the step (1) is at least one of 1, 4-butanediol, 1, 3-propanediol and 2, 3-butanediol; the dihydric alcohol containing carboxyl in the step (1) is at least one of 2, 2-dimethylolpropionic acid and dimethylolbutyric acid;

the silane coupling agent in the step (2) is a silane coupling agent containing epoxy functional groups;

the bio-based dibasic acid in the step (3) is itaconic acid.

2. The method for preparing silicon-containing aqueous UV bio-based unsaturated polyester according to claim 1, wherein:

the using amount of the bio-based diol and the carboxyl-containing diol in the step (1) is 5-30% of the total molar amount of the bio-based diol and the carboxyl-containing diol.

3. The method for preparing silicon-containing aqueous UV bio-based unsaturated polyester according to claim 1, wherein:

the catalyst in the step (2) is at least one of concentrated sulfuric acid, p-toluenesulfonic acid, N dimethyl benzylamine and triphenylphosphine;

the polymerization inhibitor in the step (2) is at least one of p-hydroxyanisole and hydroquinone (1, 4-dihydroxybenzene);

the dosage of the silane coupling agent in the step (2) meets the condition that the molar ratio of the silane coupling agent to the dihydric alcohol containing carboxyl is 1: 1;

the dosage of the catalyst in the step (2) is 0.5-1.0% of the total mass of the carboxyl-containing dihydric alcohol and the silane coupling agent;

the using amount of the polymerization inhibitor in the step (2) is 0.5-1.0% of the total mass of the carboxyl-containing dihydric alcohol and the silane coupling agent.

4. The method for preparing the silicon-containing aqueous UV bio-based unsaturated polyester according to claim 3, wherein:

the silane coupling agent in the step (2) is at least one of a silane coupling agent KH560, a silane coupling agent SCA-403 and a silane coupling agent A-186;

the catalyst in the step (2) is at least one of N, N dimethyl benzylamine and triphenylphosphine.

5. The method for preparing silicon-containing aqueous UV bio-based unsaturated polyester according to claim 1, wherein:

the modification reaction in the step (2) is carried out at 85-95 ℃ for 1.5-2.5 h until the acid value is reduced to 25-35 mg (KOH)/g.

6. The method for preparing silicon-containing aqueous UV bio-based unsaturated polyester according to claim 1, wherein:

the using amount of the bio-based dibasic acid in the step (3) is 1.1-1.5 times of the total molar amount of the bio-based dibasic acid and the carboxyl-containing dihydric alcohol in the step (1);

the catalyst in the step (3) is at least one of concentrated sulfuric acid, p-toluenesulfonic acid, N dimethyl benzylamine and triphenylphosphine; the dosage of the catalyst is 0.5-1.0% of the total mass of the itaconic acid, the bio-based dihydric alcohol and the carboxyl-containing dihydric alcohol;

at least one of p-hydroxyanisole polymerization inhibitor and hydroquinone (1, 4-dihydroxybenzene) polymerization inhibitor in the step (3); the dosage of the polymerization inhibitor is 0.5-1.0% of the total mass of the itaconic acid, the bio-based dihydric alcohol and the carboxyl-containing dihydric alcohol.

7. The method for preparing silicon-containing aqueous UV bio-based unsaturated polyester according to claim 1, wherein:

the photocuring reaction in the step (3) is carried out for 2-3 h at 135 ℃ under the protection of inert gas until the acid value reaches 200-240 mg (KOH)/g, then the temperature is kept at 135 ℃, and the vacuum pumping reaction is continued for 1-1.5 h, wherein the pressure is 0.085-0.095 MPa.

8. The method for preparing the silicon-containing aqueous UV bio-based unsaturated polyester according to claim 1, wherein:

the neutralizing agent in the step (4) is at least one of triethylamine, triethanolamine, N-dimethylethanolamine and ammonia water; the dosage of the neutralizer meets the requirement that the neutralization degree of the obtained target product is 30-45%;

the photoinitiator in the step (4) is at least one of 1173 (2-hydroxy-2-methyl-1-phenyl-1-acetone), 2959 (2-hydroxy-4' - (2-hydroxyethoxy) -2-methyl propiophenone) and polyethylene glycol (beta-4- [ p- (2-dimethylamine-2-benzyl) butyrylphenyl ] piperazine) propionate; the using amount of the photoinitiator meets the requirement that the mass fraction of the photoinitiator in the silicon-containing waterborne UV bio-based unsaturated polyester is 3-6%.

9. A silicon-containing aqueous UV bio-based unsaturated polyester prepared according to the method of any one of claims 1 to 8.

10. Use of the silicon-containing aqueous UV bio-based unsaturated polyester according to claim 9 in paper finishing, leather finishing, glass and tile finishing underlayments.