CN111944100B

CN111944100B - Preparation method of water-based acrylic resin

Info

Publication number: CN111944100B
Application number: CN201910395670.0A
Authority: CN
Inventors: 焦方军; 刘海蓉; 于海宁
Original assignee: Wanhua Chemical Group Co Ltd; Wanhua Chemical Beijing Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd; Wanhua Chemical Beijing Co Ltd
Priority date: 2019-05-14
Filing date: 2019-05-14
Publication date: 2022-07-12
Anticipated expiration: 2039-05-14
Also published as: CN111944100A

Abstract

The invention discloses a preparation method of water-based acrylic resin, which adopts a special active diluent, so that the resin prepared by the method and the further application thereof do not use a volatile organic solvent, and the environmental protection requirement of extremely low VOC content is realized; in addition, when the resin prepared by the method is applied to water-based paint, the resin has excellent comprehensive performance.

Description

Preparation method of water-based acrylic resin

Technical Field

The invention relates to a preparation method of water-based acrylic resin, which adopts a reactive diluent.

Background

With the strengthening of the overall environmental awareness of society and the increasing strictness of environmental regulations, aqueous coatings with lower VOC (volatile organic compound) emissions are rapidly replacing aqueous coatings and solvent-borne coatings with high VOC emissions. However, due to the technical limitation, the resin synthesis process and application process of the current water-based paint also need to use a large amount of cosolvent and/or film-forming additive, and the VOC of the water-based paint is generally higher. Therefore, on the premise of ensuring excellent application performance, the waterborne coating resin has great significance for protecting the environment if the content of VOC substances in the waterborne coating resin can be greatly reduced and no or less VOC substances can be used in downstream application.

The water-based acrylic resin is one of the main types of water-based paint resins, and has the characteristics of weather resistance, acid and alkali resistance, oil resistance, light and color retention, high hardness, various curing and crosslinking modes and the like. From the environmental protection perspective, the prior art can not directly prepare acrylic resin or modified acrylic resin with solid content close to 100% under the condition of no VOC substances (including solvent and cosolvent) and normal pressure.

Currently, in the more advanced high solid separation and synthesis technology of acrylic resin or modified and hybridized acrylic resin, in order to reduce the use of VOC substances, a reactive diluent and an organic solvent are mostly used in combination. The commonly used reactive diluents include alkyl glycidyl ether, glycidyl pivalate, glycidyl neoheptanoate, glycidyl neononanoate, glycidyl neodecanoate, glycidyl neotridecanoate, trimethylolpropane triglycidyl ether, glycidyl versatate, castor oil polyglycidyl ether and the like, and the compounds are used as the reactive diluents, so that the need of matching with an organic solvent cannot be avoided, and the prepared resin and coating still have higher VOC content.

Patent CN102020759A discloses a preparation method of water-based resin and a water-based coating composition. In the water-based paint composition, the content of the cosolvent accounts for 55-90 parts (wt thousandths), the content of the butanediol accounts for 10-80 parts (wt thousandths), and the VOC substance still accounts for a higher proportion.

Patent CN104558449A discloses a preparation method of a high-resistance organic-inorganic composite modified water-based acrylic resin. In the water-based paint composition, the content of the active diluent accounts for 10-15 (wt%), the content of the cosolvent accounts for 15-40 (wt%), and the content of water accounts for 0-50 (wt%). Although the amount of water added is large, the VOC content is still high.

Patent CN108467482A discloses a star-branched glycidyl versatate resin, a super-hydrophobic coating and a super-hydrophobic coating. According to the method, stannous octoate is used as a catalyst, trimethylolpropane and tertiary carbonic acid glycidyl ester react according to a molar ratio of 1: 3-9, the main component of a product is star-shaped branched resin, and the main component has a high molecular weight; the addition amount of stannous octoate serving as a catalyst is 3% of the total mass of reactants, the use amount is large, the content of heavy metal tin in a coating can seriously exceed the standard, and the environmental pollution is caused; on the other hand, in the synthesis process of the star-branched glycidyl versatate resin, although no solvent is involved, in the downstream application, a large amount of organic solvent such as butyl acetate is required to be used for dilution, the VOC content is high, and the star-branched glycidyl versatate resin still belongs to the category of solvent-based coating resin.

Therefore, it is necessary to provide a technical solution to the problems in the prior art.

Disclosure of Invention

The invention provides a preparation method of water-based acrylic resin, which adopts a special active diluent and has the beneficial effects that: firstly, the diluent can be used for not only performing normal chain transfer function and auxiliary dissolution function in the synthesis of acrylic resin, but also being used as one of film forming components when a paint film is formed and cured, and reacting and curing with a cross-linking agent; secondly, the diluent can be used as one of reactants and continuously reacts with other monomers in the synthetic process of the acrylic resin to be grafted to the macromolecules of the acrylic resin so as to reduce free micromolecular substances; thirdly, the boiling points of the raw materials used by the diluent are all higher than 250 ℃, and the raw materials can be excluded from the boiling point range required by VOC substances, so that the realization of the extremely low VOC requirement of the prepared acrylic resin is ensured; fourthly, the method can directly synthesize the acrylic resin with the solid content close to 100 percent under the conditions of no solvent participation and normal pressure, and has excellent film forming performance under the conditions of no organic solvent, no film forming additive, no plasticizer and only water dispersion when being prepared into a water-based paint.

A preparation method of acrylic resin comprises the steps of mixing a reactive diluent, an acrylic monomer and a vinyl monomer for reaction in the presence of a peroxide initiator; the reactive diluent is obtained by reacting glycidyl versatate with trimethylolpropane in the presence of a catalyst, wherein the molar ratio of the glycidyl versatate to the trimethylolpropane is 0.5-3.5: 1, preferably 0.7 to 2.9: 1, preferably 1-2: 1.

the control of the molar ratio of the tertiary carbonic acid glycidyl ester to the trimethylolpropane is beneficial to controlling the proportion of free monomers to each reaction product, improving the process safety of the low VOC acrylic resin preparation, controlling the molecular weight distribution of the acrylic resin in a reasonable range and improving the performance of a paint film.

Preferably, the dosage of the active diluent accounts for 10-60%, preferably 20-50% of the total mass of all reaction raw materials.

The acrylic monomer refers to a class of compounds having an acrylic structure and having an unsaturated double bond, and examples thereof include, but are not limited to, acrylic acid, methacrylic acid, cyclohexyl acrylate, cyclohexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, isobornyl acrylate, isobornyl methacrylate, acetoacetoxy ethyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-propyl acrylate, lauryl methacrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, n-hydroxypropyl methacrylate, and the like, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and the like, and such acrylic monomers may be used alone or in combination.

The peroxide initiator may be a peroxide initiator commonly used in the art, and examples thereof include, but are not limited to, Azobisisobutyronitrile (AIBN), Azobisisoheptonitrile (ABVN), dibenzoyl peroxide (BPO), dicumyl peroxide, t-butyl peroxybenzoate (TBPB), di-t-butyl peroxide (DTBP), di-t-amyl peroxide (DTAP), t-butyl hydroperoxide, and the like, which may be used alone or in combination.

The vinyl-based monomer refers to a type of monomer having an unsaturated double bond, having no acrylic structure, and examples thereof include, but are not limited to, styrene, acrylonitrile, vinyl acetate, acrylamide, vinyl versatate (veova10), and the like, and such vinyl-based monomers may be used alone or in combination.

In the method, a monomer including an epoxy functional group, such as glycidyl versatate, glycidyl acrylate, glycidyl methacrylate, and the like, may be further included. The monomer can participate in free radical polymerization after forming a prepolymer containing unsaturated double bonds through addition reaction with acrylic acid and methacrylic acid; or the addition reaction can be carried out in the form of a monomer with the existing acrylic acid and methacrylic acid monomers in the system in a free radical polymerization reaction stage in a step with a free radical. The method of using such monomers is a fundamental skill of those skilled in the art to be able to master.

The method may further comprise using an alkyd resin, which may be prepared by methods commonly used in the art or obtained by commercial procurement.

The method can also comprise the use of polyester resin, and the polyester resin can be prepared by a method commonly used in the field or obtained by commercial purchase.

In the method, the reaction temperature can be determined by referring to a method commonly used in the art, for example, a reaction temperature interval and the like by the half-life of the peroxide initiator. Preferably, the reaction temperature is 70-180 ℃.

In a preferred embodiment, the preparation method comprises,

and adding the reactive diluent, optional alkyd resin and optional polyester resin into a reactor in a nitrogen atmosphere, starting stirring, controlling the temperature of the reactor to be 70-180 ℃, uniformly stirring, adding an acrylic monomer, a vinyl monomer and a peroxide initiator for reaction, and discharging after the reaction is finished.

The glycidyl versatate is a common chemical raw material, and the acquisition route can be synthesized by a method commonly used in the field, and can also be obtained by commercial purchase, such as the purchase of a commercial commodity E10P and the like.

The catalyst may employ catalysts commonly used in the art, such as Lewis acids, Lewis bases, etc., and such catalysts may be used alone or in combination. Preferably, the catalyst is selected from stannous octoate and/or boron trifluoride etherate.

The amount of the catalyst can be determined by the conventional method in the field, and the method does not affect the implementation of the invention. In a preferred embodiment, the catalyst is used in an amount of 0.08 to 0.5%, preferably 0.1 to 0.2%, based on the total mass of the glycidyl versatate and trimethylolpropane.

The reactive diluent may also be prepared by using an antioxidant, examples of which include, but are not limited to, hindered phenol-based antioxidants, phosphite-based antioxidants, and the like, which may be used alone or in combination. Commercially available antioxidants such as antioxidant M070 (compounded type), antioxidant TP80 (phosphite), antioxidant 168 (phosphite), antioxidant 1010 (hindered phenol type), antioxidant 1076 (hindered phenol type), antioxidant 1098 (hindered phenol type), antioxidant M070 (compounded type), antioxidant B900 (compounded type), and the like.

In a preferred embodiment, the antioxidant is used in an amount of 0.08 to 0.5%, preferably 0.1 to 0.2%, based on the total mass of the glycidyl versatate and trimethylolpropane.

In a preferred embodiment, the preparation method of the reactive diluent comprises the steps of adding 80-90% of the total mass of the tertiary carbonic acid glycidyl ester, all trimethylolpropane and all antioxidants into a reactor in a nitrogen atmosphere, starting stirring, controlling the temperature of the reactor to be 100-130 ℃, preferably 115-125 ℃, adding a catalyst and the rest of the tertiary carbonic acid glycidyl ester after a reaction system is uniformly mixed, slowly heating the reactor to 150-200 ℃, preferably 170-180 ℃, reacting, and discharging after the reaction is finished.

The control of the adding concentration and the adding speed of the catalyst is beneficial to controlling the heat release rate of the reaction, the safe control of the temperature and the reduction of the side reaction. The stepwise rise of the reaction temperature is controlled, which is beneficial to the smoothness of the reaction heat release and the control of the reaction temperature and the molecular weight distribution range.

Preferably, the reactive diluent comprises a compound 1 and a compound 2, wherein the compound 1 is obtained by respectively subjecting two hydroxyl groups in a trimethylolpropane molecule to a ring-opening reaction with the terminal epoxy groups of two glycidyl versatate molecules, and the compound 2 is obtained by subjecting one hydroxyl group in a trimethylolpropane molecule to a ring-opening reaction with the terminal epoxy group of one glycidyl versatate molecule.

It should be noted that the reactive diluent forms a plurality of isomers during the preparation process, which is determined by the catalytic selectivity of the catalyst; the secondary hydroxyl group formed during the ring-opening of the terminal epoxy group of the starting glycidyl versatate may be formed on the first carbon atom of the terminal epoxy group and on the second carbon atom of the terminal epoxy group, so that the formation of isomers is unavoidable and the proportions of the obtained isomers differ with the use of different types of catalysts. The occurrence of isomers is in accordance with the definition of compound 1 and compound 2 in the present invention.

Further, the reactive diluent may further contain a small amount of free monomer or impurities, wherein the free monomer refers to the unreacted glycidyl versatate or trimethylolpropane in the reaction system, and even if the two types of reactants are designed to be completely reacted, the chemical reaction cannot reach a completely reacted state in the actual process, and a small amount of unreacted monomer remains, but the two types of monomers can participate in the reaction in the process of preparing the aqueous acrylic resin, and the VOC influence is not caused.

Preferably, in the reactive diluent, the content of the compound 1 is 24-84%, the content of the compound 2 is 7.5-69.5%, and the balance is free monomers or impurities, wherein the total mass of the reactive diluent is taken as a reference.

Controlling the types and the proportion of the compound 1 and the compound 2 can enable the prepared resin and coating to achieve the following beneficial effects: the compound 1 has higher molecular weight and functionality than the compound 2, so that a cross-linking curing film is more compact, and the formed paint film has more excellent mechanical properties, water resistance, chemical resistance and the like; the compound 2 is an oligomer with 3 functionalities, can form a compact structure when being crosslinked, cured and filmed, has excellent physical and chemical properties, and because the compound 2 has a simple molecular structure and a lower molecular weight than the compound 1, the compound 2 has low viscosity, good solubility, small chain transfer coefficient and the like in the radical polymerization of vinyl monomers, acrylate monomers, vinyl acetate unsaturated monomers and the like, and is beneficial to preparing acrylic resin with the solid content of nearly 100%; in a preferred embodiment of the present invention, the composition comprising compound 1 and compound 2 enables the preparation of resins and coatings that have both the benefits provided by compound 1 and compound 2, and also enables the preparation of resins and coatings that have both hydrophilic and lipophilic properties.

The preparation method of the water-based acrylic resin has the beneficial effects that: the acrylic resin with the theoretical solid content of 100 percent can be directly synthesized under the conditions of no participation of volatile organic solvent and normal pressure, and then water is added for mixing and diluting according to needs to prepare the aqueous dispersion, so that the aqueous coating resin product with extremely low VOC content is prepared, and the prepared coating further has the advantages of high drying speed, high glossiness, good fullness, extremely low VOC emission, excellent mechanical property, good storage stability and the like.

For the production method, for example, the production method of alkyd resin or polyester resin, which is not described in the above production methods, reference may be made to "coating process" third edition (chenshijie) published by chemical industry press, or other protocols described in the prior art.

The water-based acrylic resin prepared by the method can be widely applied to various fields such as coatings, printing ink, adhesives and the like, and is particularly suitable for the field of coatings.

Drawings

FIG. 1: GPC measurement results of the reactive diluent sample obtained in example 1.

FIG. 2: example 2 sample of reactive diluent GPC test results.

FIG. 3: the GPC measurement result of the reactive diluent sample obtained in example 3.

Detailed Description

Alkyd resins used in examples and comparative examples preparation methods: in the nitrogen atmosphere, 225.9g of soya-bean oil acid, 353g of trimethylolpropane, 35.1g of pentaerythritol, 361.8g of isophthalic acid and 1g of tetrabutyl titanate are added into a reactor, stirring is started, the temperature of the reactor is controlled to be 175 ℃ for reaction, after 2 hours, the temperature of the reactor is controlled to be 245 ℃ for reaction, when a reaction system is clear and transparent, the temperature of the reactor is controlled to be 175 ℃, 9.2g of maleic anhydride is added, the temperature of the reactor is controlled to be 220 ℃ for reaction, the reactor is added into a dehydration device for dehydration treatment, after 2 hours, the temperature of the reactor is controlled to be 165 ℃, 15g of maleic anhydride is added for reaction, after 3 hours, the reaction is ended, and discharging is carried out.

Preparation of polyester resins used in examples and comparative examples: under the nitrogen atmosphere, 220g of adipic acid, 120g of trimethylolpropane, 200g of neopentyl glycol, 36g of terephthalic acid, 84g of isophthalic acid and 0.8g of antioxidant M070 are added into a reactor, stirring is started, the temperature of the reactor is controlled to be 180 ℃, after 2 hours, the temperature of the reactor is controlled to be 235 ℃, 0.7g of tetrabutyl titanate is added for reaction, when a reaction system is clear and transparent, the temperature of the reactor is controlled to be 180 ℃, 15.9g of maleic anhydride is added, the temperature of the reactor is controlled to be 220 ℃, the reaction is carried out, the reactor is added into a dehydration device for dehydration treatment, after 2 hours, the temperature of the reactor is controlled to be 175 ℃ for reaction, after 2 hours, the reaction is finished, and discharging is carried out.

Example 1

The preparation method of the active diluent comprises the following steps: under the nitrogen atmosphere, 411g of glycidyl versatate, 134.18g of trimethylolpropane and 1.19g of antioxidant M070 are added into a reactor, stirring is started, the temperature of the reactor is controlled to be 120 ℃, 1.19g of stannous octoate and 45.66g of glycidyl versatate are added after 0.5 hour, the reaction temperature is controlled to be 145 ℃, the reaction temperature is controlled to be 175 ℃ after 0.5 hour, the reaction is finished after 4 hours, and discharging is carried out.

The preparation method of the water-based acrylic resin comprises the following steps: adding 400g of the reactive diluent into a reactor under a nitrogen atmosphere, starting stirring, controlling the temperature of the reactor to be 90 ℃, after 0.5 hour, mixing 100g of methyl methacrylate, 40g of styrene, 25g of isobornyl acrylate, 123.5g of butyl acrylate, 50g of butyl methacrylate, 20.6g of hydroxyethyl acrylate and 10g of azobisisobutyronitrile in advance, dropwise adding the mixture into the reactor for reaction, after 1 hour, mixing 20g of methyl methacrylate, 15g of styrene, 58g of acrylic acid, 20g of butyl acrylate, 79g of hydroxyethyl acrylate and 6g of azobisisobutyronitrile in advance, dropwise adding the mixture into the reactor, controlling the temperature of the reactor to be 95 ℃ for reaction, after 2 hours, mixing 30g of isobornyl acrylate and 2.9g of azobisisobutyronitrile in advance, dropwise adding the mixture into the reactor, controlling the temperature of the reactor to be 105 ℃ for reaction, after 3 hours, and finishing the reaction and discharging.

Example 2

The preparation method of the active diluent comprises the following steps: in the nitrogen atmosphere, 182.66g of glycidyl versatate, 134.17g of trimethylolpropane and 0.36g of antioxidant M070 are added into a reactor, the reactor is stirred, the temperature of the reactor is controlled to be 120 ℃, 0.36g of stannous octoate and 45.67g of glycidyl versatate are added after 0.5 hour, the reaction temperature is controlled to be 145 ℃, the reaction temperature is controlled to be 175 ℃ after 0.5 hour, the reaction is finished after 4 hours, and the material is discharged.

The preparation method of the water-based acrylic resin comprises the following steps: under the nitrogen atmosphere, 264.6g of alkyd resin and 147g of the reactive diluent are added into a reactor, stirring is started, the temperature of the reactor is controlled to be 145 ℃, after 0.5 hour, 5g of methyl methacrylate, 46.6g of styrene and 1.6g of di-tert-butyl peroxide are mixed in advance and then added into the reactor dropwise for reaction, after 40 minutes, 11g of methyl methacrylate, 65g of styrene, 34.5g of acrylic acid and 2.2g of di-tert-butyl peroxide are mixed in advance and then added into the reactor dropwise for reaction, after 2 hours, 10g of glycidyl versatate (E10P) and 0.51g of di-tert-butyl peroxide are mixed uniformly in advance, then added into the reaction kettle at a constant speed for 1.5 hours, after the dropwise addition is finished, the temperature is kept at 145 ℃ for 4 hours, and then the reaction discharge is finished.

Example 3

The preparation method of the active diluent comprises the following steps: in the nitrogen atmosphere, 291.12g of glycidyl versatate, 134.17g of trimethylolpropane and 0.72g of antioxidant M070 are added into a reactor, the reactor is stirred, the temperature of the reactor is controlled to be 120 ℃, 0.72g of stannous octoate and 51.38g of glycidyl versatate are added after 0.5 hour, the reaction temperature is controlled to be 145 ℃, the reaction temperature is controlled to be 175 ℃ after 0.5 hour, the reaction is finished after 4 hours, and the materials are discharged.

The preparation method of the water-based acrylic resin comprises the following steps: under the nitrogen atmosphere, 257.6g of polyester resin and 48.5g of the reactive diluent are added into a reactor, stirring is started, the temperature of the reactor is controlled to be 145 ℃, after 0.5 hour, 15g of methyl methacrylate, 26.6g of styrene, 6g of isobornyl methacrylate, 4g of hydroxyethyl acrylate and 2.3g of di-tert-amyl peroxide are mixed in advance and then added into the reactor dropwise for reaction, the temperature of the reactor is controlled to be 155 ℃ for reaction for 0.5 hour, the temperature of the reactor is controlled to be 175 ℃ for reaction for 0.5 hour, the temperature of the reactor is controlled to be 155 ℃, 15g of isobornyl acrylate and 1.2g of di-tert-amyl peroxide are mixed in advance and then added into the reactor dropwise, the temperature of the reactor is controlled to be 165 ℃ for reaction, after 4 hours, the reaction is finished, and discharging is carried out.

Comparative example 1

The preparation method of the water-based acrylic resin comprises the following steps: under nitrogen atmosphere, adding 400g of dipropylene glycol methyl ether into a reactor, starting stirring, controlling the temperature of the reactor to be 90 ℃, after 0.5 hour, mixing 100g of methyl methacrylate, 40g of styrene, 25g of isobornyl acrylate, 123.5g of butyl acrylate, 50g of butyl methacrylate, 20.6g of hydroxyethyl acrylate and 10g of azobisisobutyronitrile in advance, dropwise adding the mixture into the reactor for reaction, after 1 hour, mixing 20g of methyl methacrylate, 15g of styrene, 58g of acrylic acid, 20g of butyl acrylate, 79g of hydroxyethyl acrylate and 6g of azobisisobutyronitrile in advance, dropwise adding the mixture into the reactor, controlling the temperature of the reactor to be 95 ℃ for reaction, after 2 hours, mixing 30g of isobornyl acrylate and 2.9g of azobisisobutyronitrile in advance, dropwise adding the mixture into the reactor, controlling the temperature of the reactor to be 105 ℃ for reaction, after 3 hours, and finishing the reaction and discharging.

Comparative example 2

The preparation method of the water-based acrylic resin comprises the following steps: 264.6g of alkyd resin and 147g of dipropylene glycol methyl ether are added into a reactor under the nitrogen atmosphere, stirring is started, the temperature of the reactor is controlled to be 145 ℃, after 0.5 hour, 5g of methyl methacrylate, 46.6g of styrene and 1.6g of di-tert-butyl peroxide are mixed in advance and then added into the reactor dropwise for reaction, after 40 minutes, 11g of methyl methacrylate, 65g of styrene, 34.5g of acrylic acid and 2.2g of di-tert-butyl peroxide are mixed in advance and then added into the reactor dropwise for reaction, after 2 hours, 10g of tertiary glycidyl carbonate (E10P) and 0.51g of di-tert-butyl peroxide are mixed in advance uniformly, then the mixture is added into the reactor at a constant speed for 1.5 hours, after the addition is finished, the temperature is kept at 145 ℃ for 4 hours, and the reaction discharging is finished.

Comparative example 3

The preparation method of the water-based acrylic resin comprises the following steps: in a nitrogen atmosphere, 257.6g of polyester resin and 48.5g of dipropylene glycol methyl ether are added into a reactor, stirring is started, the temperature of the reactor is controlled to be 145 ℃, after 0.5 hour, 15g of methyl methacrylate, 26.6g of styrene, 6g of isobornyl methacrylate, 4g of hydroxyethyl acrylate and 2.3g of di-tert-amyl peroxide are mixed in advance and then added into the reactor dropwise for reaction, the temperature of the reactor is controlled to be 155 ℃ for reaction for 0.5 hour, then the temperature of the reactor is controlled to be 175 ℃ for reaction for 0.5 hour, the temperature of the reactor is controlled to be 155 ℃, 15g of isobornyl acrylate and 1.2g of di-tert-amyl peroxide are mixed in advance and then added into the reactor dropwise, the temperature of the reactor is controlled to be 165 ℃ for reaction, after 4 hours, the reaction is finished, and discharging is carried out.

GPC measurement was carried out on the samples obtained in the examples, and the measurement results are shown in Table 1.

TABLE 1

Method for preparing paint films for the examples and comparative examples: according to the types and the use amounts of the raw materials in the table 2, the raw materials are uniformly mixed in proportion, sprayed on a polished tin plate, baked for 30 minutes at 150 ℃, and after baking, test paint films are respectively obtained, wherein the thickness of the paint films is about 30-35 mu m.

TABLE 2 (parts by mass)

The solid contents of the components in table 2 can be calculated, the VOC contents of the coating samples of examples 1 to 3 are all 2.2%, and the VOC contents of the coating samples of comparative examples 1, 2, and 3 are 17.4%, 10.7%, and 6.2%, respectively.

The resulting paint films were subjected to performance tests, and the test results, test methods and standards are shown in Table 3.

TABLE 3

Claims

1. A preparation method of acrylic resin is characterized in that under the condition of the existence of peroxide initiator, reactive diluent, acrylic monomer and vinyl monomer are mixed and reacted; the reactive diluent is obtained by reacting glycidyl versatate with trimethylolpropane in the presence of a catalyst, wherein the molar ratio of the glycidyl versatate to the trimethylolpropane is 0.5-3.5: 1.

2. the method according to claim 1, wherein the molar ratio of the glycidyl versatate to trimethylolpropane is 0.7-2.9: 1.

3. the method according to claim 1 or 2, wherein the molar ratio of the glycidyl versatate to trimethylolpropane is 1-2: 1.

4. the method according to claim 1, wherein the amount of the reactive diluent is 10-60% of the total mass of all reaction raw materials.

5. The method according to claim 4, wherein the amount of the reactive diluent is 20-50% of the total mass of all reaction raw materials.

6. The method according to claim 1, wherein the reactive diluent, the optional alkyd resin and the optional polyester resin are added into a reactor under nitrogen atmosphere, stirring is started, the temperature of the reactor is controlled to be 70-180 ℃, the acrylic monomer, the vinyl monomer and the peroxide initiator are added after the uniform stirring for reaction, and discharging is carried out after the reaction is finished.

7. The process according to claim 1, characterized in that the catalyst is selected from stannous octoate and/or boron trifluoride etherate.

8. The method according to claim 7, wherein the catalyst is used in an amount of 0.08 to 0.5% based on the total mass of the glycidyl versatate and trimethylolpropane.

9. The method according to claim 8, wherein the catalyst is used in an amount of 0.1 to 0.2% based on the total mass of the glycidyl versatate and trimethylolpropane.

10. The method according to claim 1, wherein the reactive diluent is prepared by using an antioxidant in an amount of 0.08 to 0.5% based on the total mass of the glycidyl versatate and the trimethylolpropane.

11. The method according to claim 10, wherein the antioxidant is used in an amount of 0.1 to 0.2% based on the total mass of the glycidyl versatate and trimethylolpropane.

12. The method according to claim 1, wherein the reactive diluent is prepared by adding 80-90% of the total mass of the glycidyl versatate, all trimethylolpropane and all antioxidants into a reactor in a nitrogen atmosphere, starting stirring, controlling the temperature of the reactor to be 100-130 ℃, adding the catalyst and the rest of the glycidyl versatate after a reaction system is uniformly mixed, controlling the reactor to slowly raise the temperature to 150-200 ℃ for reaction, and discharging after the reaction is finished.

13. The method according to claim 12, wherein the preparation of the reactive diluent is carried out by controlling the temperature of the reactor to be 115-125 ℃ and slowly raising the temperature of the reactor to be 170-180 ℃ for reaction.

14. The method according to claim 1, wherein the reactive diluent comprises a compound 1 and a compound 2, wherein the compound 1 is obtained by ring-opening reaction of two hydroxyl groups in a trimethylolpropane molecule and terminal epoxy groups of two glycidyl versatate molecules, respectively, and the compound 2 is obtained by ring-opening reaction of one hydroxyl group in a trimethylolpropane molecule and terminal epoxy group of one glycidyl versatate molecule.

15. The method of claim 14, wherein the reactive diluent comprises 24-84% of compound 1, 7.5-69.5% of compound 2, and the balance of free monomers or impurities, based on the total mass of the reactive diluent.